Add experimental turn additional context (#24154)

## Summary

Adds experimental `additionalContext` support to `turn/start` and
`turn/steer` so clients can provide ephemeral external context, such as
browser or automation state, without turning that plumbing into a
visible user prompt or triggering user-prompt lifecycle behavior.

## API Shape

The parameter shape is:

```ts
additionalContext?: Record<string, {
  value: string
  kind: "untrusted" | "application"
}> | null
```

Example:

```json
{
  "additionalContext": {
    "browser_info": {
      "value": "Active tab is CI failures.",
      "kind": "untrusted"
    },
    "automation_info": {
      "value": "CI rerun is in progress.",
      "kind": "application"
    }
  }
}
```

The keys are opaque and caller-defined.

## Context Injection

When provided, accepted entries are inserted into model context as
hidden contextual message items, not as visible thread user-message
items.

`kind: "untrusted"` entries are inserted with role `user`:

```text
<external_${key}>${value}</external_${key}>
```

`kind: "application"` entries are inserted with role `developer`:

```text
<${key}>${value}</${key}>
```

Values are not escaped. Each value is truncated to 1k approximate tokens
before wrapping.

For `turn/start`, accepted additional context is inserted before normal
user input. For `turn/steer`, additional context is merged only when the
steer includes non-empty user input; context-only steers still reject as
empty input.

## Dedupe Strategy

`AdditionalContextStore` lives on session state and stores the latest
complete additional-context map.

Each `turn/start` or non-empty `turn/steer` treats its
`additionalContext` as the current complete set of values. Entries are
injected only when the key is new or the exact entry for that key
changed, including `value` or `kind`. After merging, the store is
replaced with the provided map, so omitted keys are removed from the
retained set and can be injected again later if reintroduced.

Omitting `additionalContext`, passing `null`, or passing an empty object
resets the store to empty and injects nothing.

## What Changed

- Threads experimental v2 `additionalContext` through app-server into
core turn start and steer handling.
- Adds separate contextual fragment types for untrusted user-role
context and application developer-role context.
- Uses pending response input items so additional context can be
combined with normal user input without treating it as prompt text.
- Adds integration coverage for start/steer flow, role routing,
dedupe/reset behavior, deletion/re-add behavior, hook-blocked input
behavior, empty context-only steer rejection, external-fragment marker
matching, and truncation.

codex-rs/analytics/src/analytics_client_tests.rs

@@ -401,6 +401,7 @@ fn sample_turn_steer_request(
                 },
             ],
             responsesapi_client_metadata: None,
+            additional_context: None,
         },
     }
 }

codex-rs/analytics/src/client_tests.rs

@@ -103,6 +103,7 @@ fn sample_turn_steer_request() -> ClientRequest {
             expected_turn_id: "turn-1".to_string(),
             input: Vec::new(),
             responsesapi_client_metadata: None,
+            additional_context: None,
         },
     }
 }

codex-rs/app-server-protocol/schema/json/ClientRequest.json

@@ -12,6 +12,28 @@
       ],
       "type": "string"
     },
+    "AdditionalContextEntry": {
+      "properties": {
+        "kind": {
+          "$ref": "#/definitions/AdditionalContextKind"
+        },
+        "value": {
+          "type": "string"
+        }
+      },
+      "required": [
+        "kind",
+        "value"
+      ],
+      "type": "object"
+    },
+    "AdditionalContextKind": {
+      "enum": [
+        "untrusted",
+        "application"
+      ],
+      "type": "string"
+    },
     "ApprovalsReviewer": {
       "description": "Configures who approval requests are routed to for review. Examples include sandbox escapes, blocked network access, MCP approval prompts, and ARC escalations. Defaults to `user`. `auto_review` uses a carefully prompted subagent to gather relevant context and apply a risk-based decision framework before approving or denying the request. The legacy value `guardian_subagent` is accepted for compatibility.",
       "enum": [

codex-rs/app-server-protocol/schema/json/codex_app_server_protocol.schemas.json

@@ -5768,6 +5768,28 @@
         ],
         "type": "string"
       },
+      "AdditionalContextEntry": {
+        "properties": {
+          "kind": {
+            "$ref": "#/definitions/v2/AdditionalContextKind"
+          },
+          "value": {
+            "type": "string"
+          }
+        },
+        "required": [
+          "kind",
+          "value"
+        ],
+        "type": "object"
+      },
+      "AdditionalContextKind": {
+        "enum": [
+          "untrusted",
+          "application"
+        ],
+        "type": "string"
+      },
       "AdditionalFileSystemPermissions": {
         "properties": {
           "entries": {

codex-rs/app-server-protocol/schema/json/codex_app_server_protocol.v2.schemas.json

@@ -164,6 +164,28 @@
       ],
       "type": "string"
     },
+    "AdditionalContextEntry": {
+      "properties": {
+        "kind": {
+          "$ref": "#/definitions/AdditionalContextKind"
+        },
+        "value": {
+          "type": "string"
+        }
+      },
+      "required": [
+        "kind",
+        "value"
+      ],
+      "type": "object"
+    },
+    "AdditionalContextKind": {
+      "enum": [
+        "untrusted",
+        "application"
+      ],
+      "type": "string"
+    },
     "AdditionalFileSystemPermissions": {
       "properties": {
         "entries": {

codex-rs/app-server-protocol/schema/json/v2/TurnStartParams.json

@@ -5,6 +5,28 @@
       "description": "A path that is guaranteed to be absolute and normalized (though it is not guaranteed to be canonicalized or exist on the filesystem).\n\nIMPORTANT: When deserializing an `AbsolutePathBuf`, a base path must be set using [AbsolutePathBufGuard::new]. If no base path is set, the deserialization will fail unless the path being deserialized is already absolute.",
       "type": "string"
     },
+    "AdditionalContextEntry": {
+      "properties": {
+        "kind": {
+          "$ref": "#/definitions/AdditionalContextKind"
+        },
+        "value": {
+          "type": "string"
+        }
+      },
+      "required": [
+        "kind",
+        "value"
+      ],
+      "type": "object"
+    },
+    "AdditionalContextKind": {
+      "enum": [
+        "untrusted",
+        "application"
+      ],
+      "type": "string"
+    },
     "ApprovalsReviewer": {
       "description": "Configures who approval requests are routed to for review. Examples include sandbox escapes, blocked network access, MCP approval prompts, and ARC escalations. Defaults to `user`. `auto_review` uses a carefully prompted subagent to gather relevant context and apply a risk-based decision framework before approving or denying the request. The legacy value `guardian_subagent` is accepted for compatibility.",
       "enum": [

codex-rs/app-server-protocol/schema/json/v2/TurnSteerParams.json

@@ -1,6 +1,28 @@
 {
   "$schema": "http://json-schema.org/draft-07/schema#",
   "definitions": {
+    "AdditionalContextEntry": {
+      "properties": {
+        "kind": {
+          "$ref": "#/definitions/AdditionalContextKind"
+        },
+        "value": {
+          "type": "string"
+        }
+      },
+      "required": [
+        "kind",
+        "value"
+      ],
+      "type": "object"
+    },
+    "AdditionalContextKind": {
+      "enum": [
+        "untrusted",
+        "application"
+      ],
+      "type": "string"
+    },
     "ByteRange": {
       "properties": {
         "end": {

codex-rs/app-server-protocol/schema/typescript/v2/AdditionalContextEntry.ts

@@ -0,0 +1,6 @@
+// GENERATED CODE! DO NOT MODIFY BY HAND!
+
+// This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
+import type { AdditionalContextKind } from "./AdditionalContextKind";
+
+export type AdditionalContextEntry = { value: string, kind: AdditionalContextKind, };

codex-rs/app-server-protocol/schema/typescript/v2/AdditionalContextKind.ts

@@ -0,0 +1,5 @@
+// GENERATED CODE! DO NOT MODIFY BY HAND!
+
+// This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
+
+export type AdditionalContextKind = "untrusted" | "application";

codex-rs/app-server-protocol/schema/typescript/v2/index.ts

@@ -7,6 +7,8 @@ export type { AccountUpdatedNotification } from "./AccountUpdatedNotification";
 export type { ActivePermissionProfile } from "./ActivePermissionProfile";
 export type { AddCreditsNudgeCreditType } from "./AddCreditsNudgeCreditType";
 export type { AddCreditsNudgeEmailStatus } from "./AddCreditsNudgeEmailStatus";
+export type { AdditionalContextEntry } from "./AdditionalContextEntry";
+export type { AdditionalContextKind } from "./AdditionalContextKind";
 export type { AdditionalFileSystemPermissions } from "./AdditionalFileSystemPermissions";
 export type { AdditionalNetworkPermissions } from "./AdditionalNetworkPermissions";
 export type { AdditionalPermissionProfile } from "./AdditionalPermissionProfile";

codex-rs/app-server-protocol/src/protocol/v2/tests.rs

@@ -3428,6 +3428,7 @@ fn turn_start_params_preserve_explicit_null_service_tier() {
         thread_id: "thread_123".to_string(),
         input: vec![],
         responsesapi_client_metadata: None,
+        additional_context: None,
         environments: None,
         cwd: None,
         runtime_workspace_roots: None,

codex-rs/app-server-protocol/src/protocol/v2/turn.rs

@@ -41,6 +41,23 @@ pub struct TurnEnvironmentParams {
     pub cwd: AbsolutePathBuf,
 }
 
+#[derive(Serialize, Deserialize, Debug, Clone, Copy, PartialEq, Eq, JsonSchema, TS)]
+#[serde(rename_all = "lowercase")]
+#[ts(rename_all = "lowercase")]
+#[ts(export_to = "v2/")]
+pub enum AdditionalContextKind {
+    Untrusted,
+    Application,
+}
+
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+#[ts(export_to = "v2/")]
+pub struct AdditionalContextEntry {
+    pub value: String,
+    pub kind: AdditionalContextKind,
+}
+
 #[derive(
     Serialize, Deserialize, Debug, Default, Clone, PartialEq, JsonSchema, TS, ExperimentalApi,
 )]
@@ -53,6 +70,10 @@ pub struct TurnStartParams {
     #[experimental("turn/start.responsesapiClientMetadata")]
     #[ts(optional = nullable)]
     pub responsesapi_client_metadata: Option<HashMap<String, String>>,
+    /// Optional client-provided context fragments keyed by an opaque source identifier.
+    #[experimental("turn/start.additionalContext")]
+    #[ts(optional = nullable)]
+    pub additional_context: Option<HashMap<String, AdditionalContextEntry>>,
     /// Optional turn-scoped environments.
     ///
     /// Omitted uses the thread sticky environments. Empty disables
@@ -141,6 +162,10 @@ pub struct TurnSteerParams {
     #[experimental("turn/steer.responsesapiClientMetadata")]
     #[ts(optional = nullable)]
     pub responsesapi_client_metadata: Option<HashMap<String, String>>,
+    /// Optional client-provided context fragments keyed by an opaque source identifier.
+    #[experimental("turn/steer.additionalContext")]
+    #[ts(optional = nullable)]
+    pub additional_context: Option<HashMap<String, AdditionalContextEntry>>,
     /// Required active turn id precondition. The request fails when it does not
     /// match the currently active turn.
     pub expected_turn_id: String,

codex-rs/app-server/src/message_processor_tracing_tests.rs

@@ -658,6 +658,7 @@ async fn turn_start_jsonrpc_span_parents_core_turn_spans() -> Result<()> {
                         text_elements: Vec::new(),
                     }],
                     responsesapi_client_metadata: None,
+                    additional_context: None,
                     cwd: None,
                     runtime_workspace_roots: None,
                     approval_policy: None,

codex-rs/app-server/src/request_processors.rs

@@ -25,6 +25,8 @@ use codex_app_server_protocol::AccountLoginCompletedNotification;
 use codex_app_server_protocol::AccountUpdatedNotification;
 use codex_app_server_protocol::AddCreditsNudgeCreditType;
 use codex_app_server_protocol::AddCreditsNudgeEmailStatus;
+use codex_app_server_protocol::AdditionalContextEntry;
+use codex_app_server_protocol::AdditionalContextKind;
 use codex_app_server_protocol::AppInfo;
 use codex_app_server_protocol::AppListUpdatedNotification;
 use codex_app_server_protocol::AppSummary;
@@ -421,6 +423,7 @@ use codex_thread_store::ThreadStore;
 use codex_thread_store::ThreadStoreError;
 use codex_utils_absolute_path::AbsolutePathBuf;
 use codex_utils_pty::DEFAULT_OUTPUT_BYTES_CAP;
+use std::collections::BTreeMap;
 use std::collections::HashMap;
 use std::collections::HashSet;
 use std::io::Error as IoError;

codex-rs/app-server/src/request_processors/turn_processor.rs

@@ -1,4 +1,6 @@
 use super::*;
+use codex_protocol::protocol::AdditionalContextEntry as CoreAdditionalContextEntry;
+use codex_protocol::protocol::AdditionalContextKind as CoreAdditionalContextKind;
 
 #[derive(Clone)]
 pub(crate) struct TurnRequestProcessor {
@@ -30,6 +32,29 @@ fn resolve_runtime_workspace_roots(
     resolved_roots
 }
 
+fn map_additional_context(
+    additional_context: Option<HashMap<String, AdditionalContextEntry>>,
+) -> BTreeMap<String, CoreAdditionalContextEntry> {
+    additional_context
+        .unwrap_or_default()
+        .into_iter()
+        .map(|(key, entry)| {
+            (
+                key,
+                CoreAdditionalContextEntry {
+                    value: entry.value,
+                    kind: match entry.kind {
+                        AdditionalContextKind::Untrusted => CoreAdditionalContextKind::Untrusted,
+                        AdditionalContextKind::Application => {
+                            CoreAdditionalContextKind::Application
+                        }
+                    },
+                },
+            )
+        })
+        .collect()
+}
+
 struct ThreadSettingsBuildParams {
     method: &'static str,
     cwd: Option<PathBuf>,
@@ -391,6 +416,7 @@ impl TurnRequestProcessor {
             .into_iter()
             .map(V2UserInput::into_core)
             .collect();
+        let additional_context = map_additional_context(params.additional_context);
         let turn_has_input = !mapped_items.is_empty();
         let thread_settings = self
             .build_thread_settings_overrides(
@@ -419,6 +445,7 @@ impl TurnRequestProcessor {
             environments: environment_selections,
             final_output_json_schema: params.output_schema,
             responsesapi_client_metadata: params.responsesapi_client_metadata,
+            additional_context,
             thread_settings,
         };
         let turn_id = self
@@ -746,10 +773,12 @@ impl TurnRequestProcessor {
             .into_iter()
             .map(V2UserInput::into_core)
             .collect();
+        let additional_context = map_additional_context(params.additional_context);
 
         let turn_id = thread
             .steer_input(
                 mapped_items,
+                additional_context,
                 Some(&params.expected_turn_id),
                 params.responsesapi_client_metadata,
             )

codex-rs/app-server/tests/suite/v2/client_metadata.rs

@@ -179,6 +179,7 @@ async fn turn_steer_updates_client_metadata_on_follow_up_responses_request_v2()
                 text_elements: Vec::new(),
             }],
             responsesapi_client_metadata: Some(steer_metadata.clone()),
+            additional_context: None,
             expected_turn_id: turn_id.clone(),
         })
         .await?;

codex-rs/app-server/tests/suite/v2/turn_start.rs

@@ -16,6 +16,8 @@ use app_test_support::write_mock_responses_config_toml_with_chatgpt_base_url;
 use app_test_support::write_models_cache;
 use codex_app_server::INPUT_TOO_LARGE_ERROR_CODE;
 use codex_app_server::INVALID_PARAMS_ERROR_CODE;
+use codex_app_server_protocol::AdditionalContextEntry;
+use codex_app_server_protocol::AdditionalContextKind;
 use codex_app_server_protocol::ByteRange;
 use codex_app_server_protocol::ClientInfo;
 use codex_app_server_protocol::CollabAgentStatus;
@@ -301,6 +303,82 @@ async fn turn_start_with_empty_input_runs_model_request() -> Result<()> {
     Ok(())
 }
 
+#[tokio::test]
+async fn turn_start_additional_context_flows_to_model_input() -> Result<()> {
+    let responses = vec![create_final_assistant_message_sse_response("Done")?];
+    let server = create_mock_responses_server_sequence_unchecked(responses).await;
+
+    let codex_home = TempDir::new()?;
+    create_config_toml(
+        codex_home.path(),
+        &server.uri(),
+        "never",
+        &BTreeMap::default(),
+    )?;
+
+    let mut mcp = McpProcess::new(codex_home.path()).await?;
+    timeout(DEFAULT_READ_TIMEOUT, mcp.initialize()).await??;
+
+    let thread_req = mcp
+        .send_thread_start_request(ThreadStartParams {
+            model: Some("mock-model".to_string()),
+            ..Default::default()
+        })
+        .await?;
+    let thread_resp: JSONRPCResponse = timeout(
+        DEFAULT_READ_TIMEOUT,
+        mcp.read_stream_until_response_message(RequestId::Integer(thread_req)),
+    )
+    .await??;
+    let ThreadStartResponse { thread, .. } = to_response::<ThreadStartResponse>(thread_resp)?;
+
+    let turn_req = mcp
+        .send_turn_start_request(TurnStartParams {
+            thread_id: thread.id,
+            input: vec![V2UserInput::Text {
+                text: "inspect tab".to_string(),
+                text_elements: Vec::new(),
+            }],
+            additional_context: Some(HashMap::from([(
+                "custom_source".to_string(),
+                AdditionalContextEntry {
+                    value: "source value".to_string(),
+                    kind: AdditionalContextKind::Untrusted,
+                },
+            )])),
+            ..Default::default()
+        })
+        .await?;
+    timeout(
+        DEFAULT_READ_TIMEOUT,
+        mcp.read_stream_until_response_message(RequestId::Integer(turn_req)),
+    )
+    .await??;
+    timeout(
+        DEFAULT_READ_TIMEOUT,
+        mcp.read_stream_until_notification_message("turn/completed"),
+    )
+    .await??;
+
+    let requests = server
+        .received_requests()
+        .await
+        .context("failed to fetch received requests")?;
+    let request = requests
+        .iter()
+        .find(|request| request.url.path().ends_with("/responses"))
+        .context("expected model request")?;
+    let body = request
+        .body_json::<Value>()
+        .context("request body should be JSON")?;
+    assert!(
+        body.to_string()
+            .contains("<external_custom_source>source value</external_custom_source>")
+    );
+
+    Ok(())
+}
+
 #[tokio::test]
 async fn turn_start_sends_originator_header() -> Result<()> {
     let responses = vec![create_final_assistant_message_sse_response("Done")?];
@@ -2069,6 +2147,7 @@ async fn turn_start_updates_sandbox_and_cwd_between_turns_v2() -> Result<()> {
                 text_elements: Vec::new(),
             }],
             responsesapi_client_metadata: None,
+            additional_context: None,
             cwd: Some(first_cwd.clone()),
             runtime_workspace_roots: None,
             approval_policy: Some(codex_app_server_protocol::AskForApproval::Never),
@@ -2111,6 +2190,7 @@ async fn turn_start_updates_sandbox_and_cwd_between_turns_v2() -> Result<()> {
                 text_elements: Vec::new(),
             }],
             responsesapi_client_metadata: None,
+            additional_context: None,
             cwd: Some(second_cwd.clone()),
             runtime_workspace_roots: None,
             approval_policy: Some(codex_app_server_protocol::AskForApproval::Never),

codex-rs/app-server/tests/suite/v2/turn_steer.rs

@@ -1,5 +1,6 @@
 #![cfg(unix)]
 
+use anyhow::Context;
 use anyhow::Result;
 use app_test_support::McpProcess;
 use app_test_support::create_mock_responses_server_sequence;
@@ -9,6 +10,8 @@ use app_test_support::to_response;
 use app_test_support::write_mock_responses_config_toml_with_chatgpt_base_url;
 use codex_app_server::INPUT_TOO_LARGE_ERROR_CODE;
 use codex_app_server::INVALID_PARAMS_ERROR_CODE;
+use codex_app_server_protocol::AdditionalContextEntry;
+use codex_app_server_protocol::AdditionalContextKind;
 use codex_app_server_protocol::JSONRPCError;
 use codex_app_server_protocol::JSONRPCNotification;
 use codex_app_server_protocol::JSONRPCResponse;
@@ -21,6 +24,8 @@ use codex_app_server_protocol::TurnSteerParams;
 use codex_app_server_protocol::TurnSteerResponse;
 use codex_app_server_protocol::UserInput as V2UserInput;
 use codex_protocol::user_input::MAX_USER_INPUT_TEXT_CHARS;
+use serde_json::Value;
+use std::collections::HashMap;
 use tempfile::TempDir;
 use tokio::time::timeout;
 
@@ -67,6 +72,7 @@ async fn turn_steer_requires_active_turn() -> Result<()> {
                 text_elements: Vec::new(),
             }],
             responsesapi_client_metadata: None,
+            additional_context: None,
             expected_turn_id: "turn-does-not-exist".to_string(),
         })
         .await?;
@@ -176,6 +182,7 @@ async fn turn_steer_rejects_oversized_text_input() -> Result<()> {
                 text_elements: Vec::new(),
             }],
             responsesapi_client_metadata: None,
+            additional_context: None,
             expected_turn_id: turn.id.clone(),
         })
         .await?;
@@ -284,6 +291,7 @@ async fn turn_steer_returns_active_turn_id() -> Result<()> {
                 text_elements: Vec::new(),
             }],
             responsesapi_client_metadata: None,
+            additional_context: None,
             expected_turn_id: turn.id.clone(),
         })
         .await?;
@@ -312,3 +320,118 @@ async fn turn_steer_returns_active_turn_id() -> Result<()> {
 
     Ok(())
 }
+
+#[tokio::test]
+async fn turn_steer_rejects_context_only_input_without_merging_context() -> Result<()> {
+    let tmp = TempDir::new()?;
+    let codex_home = tmp.path().join("codex_home");
+    std::fs::create_dir(&codex_home)?;
+    let working_directory = tmp.path().join("workdir");
+    std::fs::create_dir(&working_directory)?;
+
+    let server = create_mock_responses_server_sequence_unchecked(vec![
+        create_shell_command_sse_response(
+            vec!["sleep".to_string(), "1".to_string()],
+            Some(&working_directory),
+            Some(10_000),
+            "call_sleep",
+        )?,
+        app_test_support::create_final_assistant_message_sse_response("Done")?,
+    ])
+    .await;
+    write_mock_responses_config_toml_with_chatgpt_base_url(
+        &codex_home,
+        &server.uri(),
+        &server.uri(),
+    )?;
+    mount_analytics_capture(&server, &codex_home).await?;
+
+    let mut mcp = McpProcess::new_without_managed_config(&codex_home).await?;
+    timeout(DEFAULT_READ_TIMEOUT, mcp.initialize()).await??;
+
+    let thread_req = mcp
+        .send_thread_start_request(ThreadStartParams {
+            model: Some("mock-model".to_string()),
+            ..Default::default()
+        })
+        .await?;
+    let thread_resp: JSONRPCResponse = timeout(
+        DEFAULT_READ_TIMEOUT,
+        mcp.read_stream_until_response_message(RequestId::Integer(thread_req)),
+    )
+    .await??;
+    let ThreadStartResponse { thread, .. } = to_response::<ThreadStartResponse>(thread_resp)?;
+
+    let turn_req = mcp
+        .send_turn_start_request(TurnStartParams {
+            thread_id: thread.id.clone(),
+            input: vec![V2UserInput::Text {
+                text: "run sleep".to_string(),
+                text_elements: Vec::new(),
+            }],
+            cwd: Some(working_directory),
+            ..Default::default()
+        })
+        .await?;
+    let turn_resp: JSONRPCResponse = timeout(
+        DEFAULT_READ_TIMEOUT,
+        mcp.read_stream_until_response_message(RequestId::Integer(turn_req)),
+    )
+    .await??;
+    let TurnStartResponse { turn } = to_response::<TurnStartResponse>(turn_resp)?;
+    timeout(
+        DEFAULT_READ_TIMEOUT,
+        mcp.read_stream_until_notification_message("turn/started"),
+    )
+    .await??;
+
+    let additional_context = Some(HashMap::from([(
+        "browser_info".to_string(),
+        AdditionalContextEntry {
+            value: "tab one".to_string(),
+            kind: AdditionalContextKind::Untrusted,
+        },
+    )]));
+    let steer_req = mcp
+        .send_turn_steer_request(TurnSteerParams {
+            thread_id: thread.id.clone(),
+            input: Vec::new(),
+            responsesapi_client_metadata: None,
+            additional_context,
+            expected_turn_id: turn.id,
+        })
+        .await?;
+    let steer_error: JSONRPCError = timeout(
+        DEFAULT_READ_TIMEOUT,
+        mcp.read_stream_until_error_message(RequestId::Integer(steer_req)),
+    )
+    .await??;
+    assert_eq!(steer_error.error.code, -32600);
+    assert_eq!(steer_error.error.message, "input must not be empty");
+
+    timeout(
+        DEFAULT_READ_TIMEOUT,
+        mcp.read_stream_until_notification_message("turn/completed"),
+    )
+    .await??;
+
+    let requests = server
+        .received_requests()
+        .await
+        .context("failed to fetch received requests")?;
+    let response_requests = requests
+        .iter()
+        .filter(|request| request.url.path().ends_with("/responses"))
+        .collect::<Vec<_>>();
+    assert_eq!(response_requests.len(), 2);
+    let body = response_requests[1]
+        .body_json::<Value>()
+        .context("request body should be JSON")?;
+    assert!(
+        !body
+            .to_string()
+            .contains("<external_browser_info>tab one</external_browser_info>")
+    );
+
+    Ok(())
+}

codex-rs/core/src/agent/control_tests.rs

@@ -444,6 +444,7 @@ async fn send_input_submits_user_message() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         },
     );
@@ -598,6 +599,7 @@ async fn spawn_agent_creates_thread_and_sends_prompt() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         },
     );
@@ -770,6 +772,7 @@ async fn spawn_agent_can_fork_parent_thread_history_with_sanitized_items() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         },
     );

codex-rs/core/src/codex_delegate.rs

@@ -192,6 +192,7 @@ pub(crate) async fn run_codex_thread_one_shot(
         items: input,
         final_output_json_schema,
         responsesapi_client_metadata: None,
+        additional_context: Default::default(),
         thread_settings: Default::default(),
     })
     .await?;

codex-rs/core/src/codex_thread.rs

@@ -21,6 +21,7 @@ use codex_protocol::models::PermissionProfile;
 use codex_protocol::models::ResponseInputItem;
 use codex_protocol::models::ResponseItem;
 use codex_protocol::openai_models::ReasoningEffort;
+use codex_protocol::protocol::AdditionalContextEntry;
 use codex_protocol::protocol::AskForApproval;
 use codex_protocol::protocol::Event;
 use codex_protocol::protocol::Op;
@@ -41,6 +42,7 @@ use codex_thread_store::ThreadStoreError;
 use codex_thread_store::ThreadStoreResult;
 use codex_utils_absolute_path::AbsolutePathBuf;
 use rmcp::model::ReadResourceRequestParams;
+use std::collections::BTreeMap;
 use std::collections::HashMap;
 use std::path::PathBuf;
 use std::sync::Arc;
@@ -236,11 +238,17 @@ impl CodexThread {
     pub async fn steer_input(
         &self,
         input: Vec<UserInput>,
+        additional_context: BTreeMap<String, AdditionalContextEntry>,
         expected_turn_id: Option<&str>,
         responsesapi_client_metadata: Option<HashMap<String, String>>,
     ) -> Result<String, SteerInputError> {
         self.codex
-            .steer_input(input, expected_turn_id, responsesapi_client_metadata)
+            .steer_input(
+                input,
+                additional_context,
+                expected_turn_id,
+                responsesapi_client_metadata,
+            )
             .await
     }
 

codex-rs/core/src/context/contextual_user_message.rs

@@ -2,6 +2,7 @@ use codex_protocol::items::HookPromptItem;
 use codex_protocol::items::parse_hook_prompt_fragment;
 use codex_protocol::models::ContentItem;
 
+use super::AdditionalContextUserFragment;
 use super::EnvironmentContext;
 use super::FragmentRegistration;
 use super::FragmentRegistrationProxy;
@@ -19,6 +20,8 @@ static USER_INSTRUCTIONS_REGISTRATION: FragmentRegistrationProxy<UserInstruction
     FragmentRegistrationProxy::new();
 static ENVIRONMENT_CONTEXT_REGISTRATION: FragmentRegistrationProxy<EnvironmentContext> =
     FragmentRegistrationProxy::new();
+static ADDITIONAL_CONTEXT_REGISTRATION: FragmentRegistrationProxy<AdditionalContextUserFragment> =
+    FragmentRegistrationProxy::new();
 static SKILL_INSTRUCTIONS_REGISTRATION: FragmentRegistrationProxy<SkillInstructions> =
     FragmentRegistrationProxy::new();
 static USER_SHELL_COMMAND_REGISTRATION: FragmentRegistrationProxy<UserShellCommand> =
@@ -42,6 +45,7 @@ static LEGACY_MODEL_MISMATCH_WARNING_REGISTRATION: FragmentRegistrationProxy<
 static CONTEXTUAL_USER_FRAGMENTS: &[&dyn FragmentRegistration] = &[
     &USER_INSTRUCTIONS_REGISTRATION,
     &ENVIRONMENT_CONTEXT_REGISTRATION,
+    &ADDITIONAL_CONTEXT_REGISTRATION,
     &SKILL_INSTRUCTIONS_REGISTRATION,
     &USER_SHELL_COMMAND_REGISTRATION,
     &TURN_ABORTED_REGISTRATION,

codex-rs/core/src/context/fragment.rs

@@ -1,4 +1,5 @@
 use codex_protocol::models::ContentItem;
+use codex_protocol::models::ResponseInputItem;
 use codex_protocol::models::ResponseItem;
 use std::marker::PhantomData;
 
@@ -81,6 +82,19 @@ pub trait ContextualUserFragment {
             phase: None,
         }
     }
+
+    fn into_response_input_item(self) -> ResponseInputItem
+    where
+        Self: Sized,
+    {
+        ResponseInputItem::Message {
+            role: Self::role().to_string(),
+            content: vec![ContentItem::InputText {
+                text: self.render(),
+            }],
+            phase: None,
+        }
+    }
 }
 
 fn matches_marked_text(start_marker: &str, end_marker: &str, text: &str) -> bool {

codex-rs/core/src/context/fragments.rs

@@ -0,0 +1,92 @@
+use super::ContextualUserFragment;
+use codex_utils_string::truncate_middle_with_token_budget;
+
+const MAX_ADDITIONAL_CONTEXT_VALUE_TOKENS: usize = 1_000;
+const ADDITIONAL_CONTEXT_END_MARKER_SUFFIX: &str = ">";
+const ADDITIONAL_CONTEXT_START_MARKER_PREFIX: &str = "<external_";
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub(crate) struct AdditionalContextUserFragment {
+    key: String,
+    value: String,
+}
+
+impl AdditionalContextUserFragment {
+    pub(crate) fn new(key: String, value: String) -> Self {
+        Self { key, value }
+    }
+}
+
+impl ContextualUserFragment for AdditionalContextUserFragment {
+    fn role() -> &'static str {
+        "user"
+    }
+
+    fn markers(&self) -> (&'static str, &'static str) {
+        Self::type_markers()
+    }
+
+    fn type_markers() -> (&'static str, &'static str) {
+        (
+            ADDITIONAL_CONTEXT_START_MARKER_PREFIX,
+            ADDITIONAL_CONTEXT_END_MARKER_SUFFIX,
+        )
+    }
+
+    fn matches_text(text: &str) -> bool {
+        let trimmed = text.trim();
+        let Some(rest) = trimmed.strip_prefix(ADDITIONAL_CONTEXT_START_MARKER_PREFIX) else {
+            return false;
+        };
+        let Some((key, value_and_close)) = rest.split_once(ADDITIONAL_CONTEXT_END_MARKER_SUFFIX)
+        else {
+            return false;
+        };
+
+        value_and_close.ends_with(&format!("</external_{key}>"))
+    }
+
+    fn body(&self) -> String {
+        additional_context_body(&self.key, &self.value)
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub(crate) struct AdditionalContextDeveloperFragment {
+    key: String,
+    value: String,
+}
+
+impl AdditionalContextDeveloperFragment {
+    pub(crate) fn new(key: String, value: String) -> Self {
+        Self { key, value }
+    }
+}
+
+impl ContextualUserFragment for AdditionalContextDeveloperFragment {
+    fn role() -> &'static str {
+        "developer"
+    }
+
+    fn markers(&self) -> (&'static str, &'static str) {
+        Self::type_markers()
+    }
+
+    fn type_markers() -> (&'static str, &'static str) {
+        ("", "")
+    }
+
+    fn body(&self) -> String {
+        additional_context_developer_body(&self.key, &self.value)
+    }
+}
+
+fn additional_context_body(key: &str, value: &str) -> String {
+    let value = truncate_middle_with_token_budget(value, MAX_ADDITIONAL_CONTEXT_VALUE_TOKENS).0;
+    format!("{key}>{value}</external_{key}")
+}
+
+fn additional_context_developer_body(key: &str, value: &str) -> String {
+    let value = truncate_middle_with_token_budget(value, MAX_ADDITIONAL_CONTEXT_VALUE_TOKENS).0;
+    format!("<{key}>{value}</{key}>")
+}

codex-rs/core/src/context/goal_context.rs

@@ -1,8 +1,6 @@
 //! Hidden user-context fragment for runtime-owned goal steering prompts.
 
 use super::ContextualUserFragment;
-use codex_protocol::models::ContentItem;
-use codex_protocol::models::ResponseInputItem;
 
 /// Hidden runtime-owned goal steering context injected into model input.
 #[derive(Debug, Clone, PartialEq)]
@@ -17,17 +15,6 @@ impl GoalContext {
             prompt: prompt.into(),
         }
     }
-
-    /// Converts the registered fragment into an active-turn injectable item.
-    pub fn into_response_input_item(self) -> ResponseInputItem {
-        ResponseInputItem::Message {
-            role: <Self as ContextualUserFragment>::role().to_string(),
-            content: vec![ContentItem::InputText {
-                text: self.render(),
-            }],
-            phase: None,
-        }
-    }
 }
 
 impl ContextualUserFragment for GoalContext {

codex-rs/core/src/context/mod.rs

@@ -8,6 +8,7 @@ mod collaboration_mode_instructions;
 mod contextual_user_message;
 mod environment_context;
 mod fragment;
+mod fragments;
 mod goal_context;
 mod guardian_followup_review_reminder;
 mod hook_additional_context;
@@ -40,6 +41,8 @@ pub(crate) use environment_context::EnvironmentContext;
 pub use fragment::ContextualUserFragment;
 pub(crate) use fragment::FragmentRegistration;
 pub(crate) use fragment::FragmentRegistrationProxy;
+pub(crate) use fragments::AdditionalContextDeveloperFragment;
+pub(crate) use fragments::AdditionalContextUserFragment;
 pub use goal_context::GoalContext;
 pub(crate) use guardian_followup_review_reminder::GuardianFollowupReviewReminder;
 pub(crate) use hook_additional_context::HookAdditionalContext;

codex-rs/core/src/goals.rs

@@ -5,6 +5,7 @@
 //! events, and owns helper hooks used by goal lifecycle behavior.
 
 use crate::StateDbHandle;
+use crate::context::ContextualUserFragment;
 use crate::context::GoalContext;
 use crate::session::TurnInput;
 use crate::session::session::Session;

codex-rs/core/src/guardian/review_session.rs

@@ -714,6 +714,7 @@ async fn run_review_on_session(
             environments: None,
             final_output_json_schema: Some(params.schema.clone()),
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 #[allow(deprecated)]
                 cwd: Some(params.parent_turn.cwd.to_path_buf()),

codex-rs/core/src/session/handlers.rs

@@ -10,6 +10,7 @@ use tracing::debug_span;
 use tracing::info_span;
 
 use crate::session::SteerInputError;
+use crate::session::TurnInput;
 use crate::session::session::Session;
 use crate::session::session::SessionSettingsUpdate;
 
@@ -194,6 +195,7 @@ pub(super) async fn user_input_or_turn_inner(
         environments,
         final_output_json_schema,
         responsesapi_client_metadata,
+        additional_context,
         thread_settings,
     } = op
     else {
@@ -224,6 +226,7 @@ pub(super) async fn user_input_or_turn_inner(
     let accepted_items = match sess
         .steer_input(
             items.clone(),
+            additional_context.clone(),
             /*expected_turn_id*/ None,
             responsesapi_client_metadata.clone(),
         )
@@ -246,9 +249,20 @@ pub(super) async fn user_input_or_turn_inner(
             )
             .await;
             let accepted_items = items.clone();
+            let additional_context_input = {
+                let mut state = sess.state.lock().await;
+                state.additional_context.merge(additional_context)
+            };
+            let mut task_input = additional_context_input
+                .into_iter()
+                .map(TurnInput::ResponseInputItem)
+                .collect::<Vec<_>>();
+            if !items.is_empty() {
+                task_input.push(TurnInput::UserInput(items));
+            }
             sess.spawn_task(
                 Arc::clone(&current_context),
-                items,
+                task_input,
                 crate::tasks::RegularTask::new(),
             )
             .await;

codex-rs/core/src/session/input_queue.rs

@@ -156,13 +156,13 @@ impl InputQueue {
             .accept_mailbox_delivery_for_current_turn();
     }
 
-    pub(super) async fn push_pending_input_and_accept_mailbox_delivery_for_turn_state(
+    pub(super) async fn extend_pending_input_and_accept_mailbox_delivery_for_turn_state(
         &self,
         turn_state: &Mutex<TurnState>,
-        input: TurnInput,
+        input: Vec<TurnInput>,
     ) {
         let mut turn_state = turn_state.lock().await;
-        turn_state.pending_input.items.push(input);
+        turn_state.pending_input.items.extend(input);
         turn_state.accept_mailbox_delivery_for_current_turn();
     }
 

codex-rs/core/src/session/mod.rs

@@ -1,3 +1,4 @@
+use std::collections::BTreeMap;
 use std::collections::HashMap;
 use std::collections::HashSet;
 use std::fmt::Debug;
@@ -97,6 +98,7 @@ use codex_protocol::openai_models::ModelInfo;
 use codex_protocol::openai_models::ModelPreset;
 use codex_protocol::permissions::FileSystemSandboxPolicy;
 use codex_protocol::permissions::NetworkSandboxPolicy;
+use codex_protocol::protocol::AdditionalContextEntry;
 use codex_protocol::protocol::FileChange;
 use codex_protocol::protocol::HasLegacyEvent;
 use codex_protocol::protocol::InterAgentCommunication;
@@ -742,11 +744,17 @@ impl Codex {
     pub async fn steer_input(
         &self,
         input: Vec<UserInput>,
+        additional_context: BTreeMap<String, AdditionalContextEntry>,
         expected_turn_id: Option<&str>,
         responsesapi_client_metadata: Option<HashMap<String, String>>,
     ) -> Result<String, SteerInputError> {
         self.session
-            .steer_input(input, expected_turn_id, responsesapi_client_metadata)
+            .steer_input(
+                input,
+                additional_context,
+                expected_turn_id,
+                responsesapi_client_metadata,
+            )
             .await
     }
 
@@ -1086,6 +1094,7 @@ impl Session {
                 }],
                 final_output_json_schema: None,
                 responsesapi_client_metadata: None,
+                additional_context: Default::default(),
                 thread_settings: Default::default(),
             },
             /*mirror_user_text_to_realtime*/ None,
@@ -3152,6 +3161,7 @@ impl Session {
     pub async fn steer_input(
         &self,
         input: Vec<UserInput>,
+        additional_context: BTreeMap<String, AdditionalContextEntry>,
         expected_turn_id: Option<&str>,
         responsesapi_client_metadata: Option<HashMap<String, String>>,
     ) -> Result<String, SteerInputError> {
@@ -3192,6 +3202,11 @@ impl Session {
             return Err(SteerInputError::EmptyInput);
         }
 
+        let additional_context_input = {
+            let mut state = self.state.lock().await;
+            state.additional_context.merge(additional_context)
+        };
+
         if let Some(responsesapi_client_metadata) = responsesapi_client_metadata {
             active_task
                 .turn_context
@@ -3199,10 +3214,15 @@ impl Session {
                 .set_responsesapi_client_metadata(responsesapi_client_metadata);
         }
 
+        let mut pending_input = additional_context_input
+            .into_iter()
+            .map(TurnInput::ResponseInputItem)
+            .collect::<Vec<_>>();
+        pending_input.push(TurnInput::UserInput(input));
         self.input_queue
-            .push_pending_input_and_accept_mailbox_delivery_for_turn_state(
+            .extend_pending_input_and_accept_mailbox_delivery_for_turn_state(
                 active_turn.turn_state.as_ref(),
-                TurnInput::UserInput(input),
+                pending_input,
             )
             .await;
         Ok(active_turn_id.clone())

codex-rs/core/src/session/review.rs

@@ -132,11 +132,11 @@ pub(super) async fn spawn_review_thread(
     };
 
     // Seed the child task with the review prompt as the initial user message.
-    let input: Vec<UserInput> = vec![UserInput::Text {
+    let input = vec![TurnInput::UserInput(vec![UserInput::Text {
         text: review_prompt,
         // Review prompt is synthesized; no UI element ranges to preserve.
         text_elements: Vec::new(),
-    }];
+    }])];
     let tc = Arc::new(review_turn_context);
     tc.turn_metadata_state.spawn_git_enrichment_task();
     // TODO(ccunningham): Review turns currently rely on `spawn_task` for TurnComplete but do not

codex-rs/core/src/session/tests.rs

@@ -2287,6 +2287,7 @@ async fn fork_startup_context_then_first_turn_diff_snapshot() -> anyhow::Result<
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -2333,6 +2334,7 @@ async fn fork_startup_context_then_first_turn_diff_snapshot() -> anyhow::Result<
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: ThreadSettingsOverrides {
                 approval_policy: Some(AskForApproval::Never),
                 collaboration_mode: Some(collaboration_mode),
@@ -5430,6 +5432,7 @@ fn op_kind_for_input_and_context_ops() {
             items: vec![],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         }
         .kind(),
@@ -5460,6 +5463,7 @@ async fn user_turn_updates_approvals_reviewer() {
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(config.cwd.to_path_buf()),
                 approval_policy: Some(config.permissions.approval_policy.value()),
@@ -5781,10 +5785,10 @@ async fn spawn_task_turn_span_inherits_dispatch_trace_context() {
     async {
         sess.spawn_task(
             Arc::clone(&tc),
-            vec![UserInput::Text {
+            vec![TurnInput::UserInput(vec![UserInput::Text {
                 text: "hello".to_string(),
                 text_elements: Vec::new(),
-            }],
+            }])],
             TraceCaptureTask {
                 captured_trace: Arc::clone(&captured_trace),
             },
@@ -6592,10 +6596,10 @@ async fn spawn_task_does_not_update_previous_turn_settings_for_non_run_turn_task
     let (sess, tc, _rx) = make_session_and_context_with_rx().await;
     sess.set_previous_turn_settings(/*previous_turn_settings*/ None)
         .await;
-    let input = vec![UserInput::Text {
+    let input = vec![TurnInput::UserInput(vec![UserInput::Text {
         text: "hello".to_string(),
         text_elements: Vec::new(),
-    }];
+    }])];
 
     sess.spawn_task(
         Arc::clone(&tc),
@@ -7861,10 +7865,10 @@ impl SessionTask for GuardianDeniedApprovalTask {
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
 async fn guardian_auto_review_interrupts_after_three_consecutive_denials() {
     let (sess, tc, rx) = make_session_and_context_with_rx().await;
-    let input = vec![UserInput::Text {
+    let input = vec![TurnInput::UserInput(vec![UserInput::Text {
         text: "trigger guardian denials".to_string(),
         text_elements: Vec::new(),
-    }];
+    }])];
     sess.spawn_task(Arc::clone(&tc), input, GuardianDeniedApprovalTask)
         .await;
 
@@ -7892,10 +7896,10 @@ async fn guardian_auto_review_interrupts_after_three_consecutive_denials() {
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
 async fn guardian_helper_review_interrupts_after_three_consecutive_denials() {
     let (sess, tc, rx) = make_session_and_context_with_rx().await;
-    let input = vec![UserInput::Text {
+    let input = vec![TurnInput::UserInput(vec![UserInput::Text {
         text: "keep turn active for helper reviews".to_string(),
         text_elements: Vec::new(),
-    }];
+    }])];
     sess.spawn_task(
         Arc::clone(&tc),
         input,
@@ -7952,10 +7956,10 @@ async fn guardian_helper_review_interrupts_after_three_consecutive_denials() {
 #[test_log::test]
 async fn abort_regular_task_emits_turn_aborted_only() {
     let (sess, tc, rx) = make_session_and_context_with_rx().await;
-    let input = vec![UserInput::Text {
+    let input = vec![TurnInput::UserInput(vec![UserInput::Text {
         text: "hello".to_string(),
         text_elements: Vec::new(),
-    }];
+    }])];
     sess.spawn_task(
         Arc::clone(&tc),
         input,
@@ -7985,10 +7989,10 @@ async fn abort_regular_task_emits_turn_aborted_only() {
 #[tokio::test]
 async fn abort_gracefully_emits_turn_aborted_only() {
     let (sess, tc, rx) = make_session_and_context_with_rx().await;
-    let input = vec![UserInput::Text {
+    let input = vec![TurnInput::UserInput(vec![UserInput::Text {
         text: "hello".to_string(),
         text_elements: Vec::new(),
-    }];
+    }])];
     sess.spawn_task(
         Arc::clone(&tc),
         input,
@@ -8018,10 +8022,10 @@ async fn abort_gracefully_emits_turn_aborted_only() {
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
 async fn task_finish_emits_turn_item_lifecycle_for_leftover_pending_user_input() {
     let (sess, tc, rx) = make_session_and_context_with_rx().await;
-    let input = vec![UserInput::Text {
+    let input = vec![TurnInput::UserInput(vec![UserInput::Text {
         text: "hello".to_string(),
         text_elements: Vec::new(),
-    }];
+    }])];
     sess.spawn_task(
         Arc::clone(&tc),
         input,
@@ -8044,6 +8048,7 @@ async fn task_finish_emits_turn_item_lifecycle_for_leftover_pending_user_input()
     }];
     sess.steer_input(
         pending_user_input.clone(),
+        /*additional_context*/ Default::default(),
         Some(&tc.sub_id),
         /*responsesapi_client_metadata*/ None,
     )
@@ -8140,7 +8145,10 @@ async fn steer_input_requires_active_turn() {
 
     let err = sess
         .steer_input(
-            input, /*expected_turn_id*/ None, /*responsesapi_client_metadata*/ None,
+            input,
+            /*additional_context*/ Default::default(),
+            /*expected_turn_id*/ None,
+            /*responsesapi_client_metadata*/ None,
         )
         .await
         .expect_err("steering without active turn should fail");
@@ -8151,10 +8159,10 @@ async fn steer_input_requires_active_turn() {
 #[tokio::test]
 async fn steer_input_enforces_expected_turn_id() {
     let (sess, tc, _rx) = make_session_and_context_with_rx().await;
-    let input = vec![UserInput::Text {
+    let input = vec![TurnInput::UserInput(vec![UserInput::Text {
         text: "hello".to_string(),
         text_elements: Vec::new(),
-    }];
+    }])];
     sess.spawn_task(
         Arc::clone(&tc),
         input,
@@ -8172,6 +8180,7 @@ async fn steer_input_enforces_expected_turn_id() {
     let err = sess
         .steer_input(
             steer_input,
+            /*additional_context*/ Default::default(),
             Some("different-turn-id"),
             /*responsesapi_client_metadata*/ None,
         )
@@ -8196,10 +8205,10 @@ async fn steer_input_rejects_non_regular_turns() {
         (TaskKind::Compact, NonSteerableTurnKind::Compact),
     ] {
         let (sess, _tc, _rx) = make_session_and_context_with_rx().await;
-        let input = vec![UserInput::Text {
+        let input = vec![TurnInput::UserInput(vec![UserInput::Text {
             text: "hello".to_string(),
             text_elements: Vec::new(),
-        }];
+        }])];
         let turn_context = sess.new_default_turn_with_sub_id("turn".to_string()).await;
         sess.spawn_task(
             turn_context,
@@ -8218,6 +8227,7 @@ async fn steer_input_rejects_non_regular_turns() {
         let err = sess
             .steer_input(
                 steer_input,
+                /*additional_context*/ Default::default(),
                 /*expected_turn_id*/ None,
                 /*responsesapi_client_metadata*/ None,
             )
@@ -8233,10 +8243,10 @@ async fn steer_input_rejects_non_regular_turns() {
 #[tokio::test]
 async fn steer_input_returns_active_turn_id() {
     let (sess, tc, _rx) = make_session_and_context_with_rx().await;
-    let input = vec![UserInput::Text {
+    let input = vec![TurnInput::UserInput(vec![UserInput::Text {
         text: "hello".to_string(),
         text_elements: Vec::new(),
-    }];
+    }])];
     sess.spawn_task(
         Arc::clone(&tc),
         input,
@@ -8254,6 +8264,7 @@ async fn steer_input_returns_active_turn_id() {
     let turn_id = sess
         .steer_input(
             steer_input,
+            /*additional_context*/ Default::default(),
             Some(&tc.sub_id),
             /*responsesapi_client_metadata*/ None,
         )
@@ -8478,6 +8489,7 @@ async fn active_goal_continuation_runs_again_after_no_tool_turn() -> anyhow::Res
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -8583,6 +8595,7 @@ async fn pending_request_user_input_does_not_spawn_extra_goal_continuation() ->
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -9130,6 +9143,7 @@ async fn completed_goal_accounts_current_turn_tokens_before_tool_response() -> a
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -9296,6 +9310,7 @@ async fn steered_input_reopens_mailbox_delivery_for_current_turn() {
             text: "follow up".to_string(),
             text_elements: Vec::new(),
         }],
+        /*additional_context*/ Default::default(),
         Some(&tc.sub_id),
         /*responsesapi_client_metadata*/ None,
     )
@@ -9345,6 +9360,7 @@ async fn stale_defer_mailbox_delivery_does_not_override_steered_input() {
             text: "follow up".to_string(),
             text_elements: Vec::new(),
         }],
+        /*additional_context*/ Default::default(),
         Some(&tc.sub_id),
         /*responsesapi_client_metadata*/ None,
     )
@@ -9426,10 +9442,10 @@ async fn tool_calls_reopen_mailbox_delivery_for_current_turn() {
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
 async fn abort_review_task_emits_exited_then_aborted_and_records_history() {
     let (sess, tc, rx) = make_session_and_context_with_rx().await;
-    let input = vec![UserInput::Text {
+    let input = vec![TurnInput::UserInput(vec![UserInput::Text {
         text: "start review".to_string(),
         text_elements: Vec::new(),
-    }];
+    }])];
     sess.spawn_task(Arc::clone(&tc), input, ReviewTask::new())
         .await;
 

codex-rs/core/src/session/turn.rs

@@ -407,14 +407,16 @@ async fn run_hooks_and_record_inputs(
     input: &[TurnInput],
 ) -> bool {
     let mut blocked_input = false;
-    let mut accepted_input = false;
+    let mut accepted_user_input = false;
     for input_item in input {
         let hook_outcome = inspect_pending_input(sess, turn_context, input_item).await;
         if hook_outcome.should_stop {
             blocked_input = true;
             record_additional_contexts(sess, turn_context, hook_outcome.additional_contexts).await;
         } else {
-            accepted_input = true;
+            if matches!(input_item, TurnInput::UserInput(items) if !items.is_empty()) {
+                accepted_user_input = true;
+            }
             record_pending_input(
                 sess,
                 turn_context,
@@ -424,7 +426,7 @@ async fn run_hooks_and_record_inputs(
             .await;
         }
     }
-    blocked_input && !accepted_input
+    blocked_input && !accepted_user_input
 }
 
 #[expect(

codex-rs/core/src/state/additional_context.rs

@@ -0,0 +1,37 @@
+use std::collections::BTreeMap;
+
+use crate::context::AdditionalContextDeveloperFragment;
+use crate::context::AdditionalContextUserFragment;
+use crate::context::ContextualUserFragment;
+use codex_protocol::models::ResponseInputItem;
+use codex_protocol::protocol::AdditionalContextEntry;
+use codex_protocol::protocol::AdditionalContextKind;
+
+#[derive(Debug, Clone, Default, PartialEq, Eq)]
+pub(crate) struct AdditionalContextStore {
+    values: BTreeMap<String, AdditionalContextEntry>,
+}
+
+impl AdditionalContextStore {
+    pub(crate) fn merge(
+        &mut self,
+        values: BTreeMap<String, AdditionalContextEntry>,
+    ) -> Vec<ResponseInputItem> {
+        let fragments = values
+            .iter()
+            .filter(|(key, value)| self.values.get(*key) != Some(*value))
+            .map(|(key, entry)| match entry.kind {
+                AdditionalContextKind::Untrusted => {
+                    AdditionalContextUserFragment::new(key.clone(), entry.value.clone())
+                        .into_response_input_item()
+                }
+                AdditionalContextKind::Application => {
+                    AdditionalContextDeveloperFragment::new(key.clone(), entry.value.clone())
+                        .into_response_input_item()
+                }
+            })
+            .collect();
+        self.values = values;
+        fragments
+    }
+}

codex-rs/core/src/state/mod.rs

@@ -1,8 +1,10 @@
+mod additional_context;
 mod auto_compact_window;
 mod service;
 mod session;
 mod turn;
 
+pub(crate) use additional_context::AdditionalContextStore;
 pub(crate) use auto_compact_window::AutoCompactWindowSnapshot;
 pub(crate) use service::SessionServices;
 pub(crate) use session::SessionState;

codex-rs/core/src/state/session.rs

@@ -6,6 +6,7 @@ use codex_sandboxing::policy_transforms::merge_permission_profiles;
 use std::collections::HashSet;
 use std::collections::VecDeque;
 
+use super::AdditionalContextStore;
 use super::auto_compact_window::AutoCompactWindow;
 use super::auto_compact_window::AutoCompactWindowSnapshot;
 use crate::context_manager::ContextManager;
@@ -25,6 +26,7 @@ pub(crate) struct SessionState {
     pub(crate) latest_rate_limits: Option<RateLimitSnapshot>,
     pub(crate) server_reasoning_included: bool,
     pub(crate) mcp_dependency_prompted: HashSet<String>,
+    pub(crate) additional_context: AdditionalContextStore,
     /// Settings used by the latest regular user turn, used for turn-to-turn
     /// model/realtime handling on subsequent regular turns (including full-context
     /// reinjection after resume or `/compact`).
@@ -49,6 +51,7 @@ impl SessionState {
             latest_rate_limits: None,
             server_reasoning_included: false,
             mcp_dependency_prompted: HashSet::new(),
+            additional_context: AdditionalContextStore::default(),
             previous_turn_settings: None,
             auto_compact_window: AutoCompactWindow::new(),
             startup_prewarm: None,

codex-rs/core/src/tasks/mod.rs

@@ -50,7 +50,6 @@ use codex_protocol::protocol::TurnAbortReason;
 use codex_protocol::protocol::TurnAbortedEvent;
 use codex_protocol::protocol::TurnCompleteEvent;
 use codex_protocol::protocol::WarningEvent;
-use codex_protocol::user_input::UserInput;
 
 use codex_features::Feature;
 use codex_protocol::models::ContentItem;
@@ -303,7 +302,7 @@ impl Session {
     pub async fn spawn_task<T: SessionTask>(
         self: &Arc<Self>,
         turn_context: Arc<TurnContext>,
-        input: Vec<UserInput>,
+        input: Vec<TurnInput>,
         task: T,
     ) {
         self.abort_all_tasks(TurnAbortReason::Replaced).await;
@@ -314,7 +313,7 @@ impl Session {
     pub(crate) async fn start_task<T: SessionTask>(
         self: &Arc<Self>,
         turn_context: Arc<TurnContext>,
-        input: Vec<UserInput>,
+        input: Vec<TurnInput>,
         task: T,
     ) {
         let task: Arc<dyn AnySessionTask> = Arc::new(task);
@@ -382,11 +381,7 @@ impl Session {
         ));
         let ctx = Arc::clone(&turn_context);
         let task_for_run = Arc::clone(&task);
-        let task_input = if input.is_empty() {
-            Vec::new()
-        } else {
-            vec![TurnInput::UserInput(input)]
-        };
+        let task_input = input;
         let task_cancellation_token = cancellation_token.child_token();
         // Task-owned turn spans keep a core-owned span open for the
         // full task lifecycle after the submission dispatch span ends.

codex-rs/core/src/tools/handlers/multi_agents_tests.rs

@@ -2592,6 +2592,7 @@ async fn send_input_accepts_structured_items() {
         ],
         final_output_json_schema: None,
         responsesapi_client_metadata: None,
+        additional_context: Default::default(),
         thread_settings: Default::default(),
     };
     let captured = manager

codex-rs/core/tests/common/test_codex.rs

@@ -767,6 +767,7 @@ impl TestCodex {
                 environments,
                 final_output_json_schema: None,
                 responsesapi_client_metadata: None,
+                additional_context: Default::default(),
                 thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                     cwd: Some(self.config.cwd.to_path_buf()),
                     approval_policy: Some(approval_policy),

codex-rs/core/tests/suite/abort_tasks.rs

@@ -53,6 +53,7 @@ async fn interrupt_long_running_tool_emits_turn_aborted() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -110,6 +111,7 @@ async fn interrupt_tool_records_history_entries() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -131,6 +133,7 @@ async fn interrupt_tool_records_history_entries() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -214,6 +217,7 @@ async fn interrupt_persists_turn_aborted_marker_in_next_request() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -235,6 +239,7 @@ async fn interrupt_persists_turn_aborted_marker_in_next_request() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await

codex-rs/core/tests/suite/additional_context.rs

@@ -0,0 +1,581 @@
+use anyhow::Result;
+use codex_protocol::items::TurnItem;
+use codex_protocol::protocol::AdditionalContextEntry;
+use codex_protocol::protocol::AdditionalContextKind;
+use codex_protocol::protocol::EventMsg;
+use codex_protocol::protocol::ItemCompletedEvent;
+use codex_protocol::protocol::Op;
+use codex_protocol::user_input::UserInput;
+use core_test_support::context_snapshot;
+use core_test_support::context_snapshot::ContextSnapshotOptions;
+use core_test_support::context_snapshot::ContextSnapshotRenderMode;
+use core_test_support::responses::ev_completed;
+use core_test_support::responses::ev_response_created;
+use core_test_support::responses::mount_sse_once;
+use core_test_support::responses::sse;
+use core_test_support::responses::start_mock_server;
+use core_test_support::skip_if_no_network;
+use core_test_support::test_codex::test_codex;
+use core_test_support::wait_for_event_match;
+use pretty_assertions::assert_eq;
+use std::collections::BTreeMap;
+
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn additional_context_is_model_visible_but_not_a_user_message_item() -> Result<()> {
+    skip_if_no_network!(Ok(()));
+
+    let server = start_mock_server().await;
+    let request = mount_sse_once(
+        &server,
+        sse(vec![ev_response_created("resp-1"), ev_completed("resp-1")]),
+    )
+    .await;
+    let test = test_codex()
+        .with_config(|config| config.include_environment_context = false)
+        .build(&server)
+        .await?;
+
+    test.codex
+        .submit(Op::UserInput {
+            environments: None,
+            items: vec![UserInput::Text {
+                text: "inspect the active tab".to_string(),
+                text_elements: Vec::new(),
+            }],
+            final_output_json_schema: None,
+            responsesapi_client_metadata: None,
+            additional_context: BTreeMap::from([
+                (
+                    "browser_info".to_string(),
+                    AdditionalContextEntry {
+                        value: "tab one".to_string(),
+                        kind: AdditionalContextKind::Untrusted,
+                    },
+                ),
+                (
+                    "automation_info".to_string(),
+                    AdditionalContextEntry {
+                        value: "run one".to_string(),
+                        kind: AdditionalContextKind::Application,
+                    },
+                ),
+            ]),
+            thread_settings: Default::default(),
+        })
+        .await?;
+
+    let user_item = wait_for_event_match(&test.codex, |event| match event {
+        EventMsg::ItemCompleted(ItemCompletedEvent {
+            item: TurnItem::UserMessage(item),
+            ..
+        }) => Some(item.clone()),
+        _ => None,
+    })
+    .await;
+    assert_eq!(
+        user_item.content,
+        vec![UserInput::Text {
+            text: "inspect the active tab".to_string(),
+            text_elements: Vec::new(),
+        }]
+    );
+    wait_for_event_match(&test.codex, |event| {
+        matches!(event, EventMsg::TurnComplete(_)).then_some(())
+    })
+    .await;
+
+    let request = request.single_request();
+    insta::assert_snapshot!(
+        "additional_context_simple_input",
+        context_snapshot::format_labeled_requests_snapshot(
+            "additional context is inserted before the user turn input.",
+            &[("Request", &request)],
+            &ContextSnapshotOptions::default()
+                .strip_capability_instructions()
+                .render_mode(ContextSnapshotRenderMode::KindWithTextPrefix { max_chars: 160 }),
+        )
+    );
+    let developer_context_texts = request
+        .message_input_texts("developer")
+        .into_iter()
+        .filter(|text| text.starts_with("<automation_info>"))
+        .collect::<Vec<_>>();
+    assert_eq!(
+        developer_context_texts,
+        vec!["<automation_info>run one</automation_info>"]
+    );
+    assert_eq!(
+        request.message_input_texts("user"),
+        vec![
+            "<external_browser_info>tab one</external_browser_info>",
+            "inspect the active tab",
+        ]
+    );
+
+    Ok(())
+}
+
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn external_context_like_user_text_remains_a_user_message_item() -> Result<()> {
+    skip_if_no_network!(Ok(()));
+
+    let server = start_mock_server().await;
+    let request = mount_sse_once(
+        &server,
+        sse(vec![ev_response_created("resp-1"), ev_completed("resp-1")]),
+    )
+    .await;
+    let test = test_codex()
+        .with_config(|config| config.include_environment_context = false)
+        .build(&server)
+        .await?;
+    let user_input = UserInput::Text {
+        text: "<external_api>".to_string(),
+        text_elements: Vec::new(),
+    };
+
+    test.codex
+        .submit(Op::UserInput {
+            environments: None,
+            items: vec![user_input.clone()],
+            final_output_json_schema: None,
+            responsesapi_client_metadata: None,
+            additional_context: BTreeMap::new(),
+            thread_settings: Default::default(),
+        })
+        .await?;
+
+    let user_item = wait_for_event_match(&test.codex, |event| match event {
+        EventMsg::ItemCompleted(ItemCompletedEvent {
+            item: TurnItem::UserMessage(item),
+            ..
+        }) => Some(item.clone()),
+        _ => None,
+    })
+    .await;
+    assert_eq!(user_item.content, vec![user_input]);
+    wait_for_event_match(&test.codex, |event| {
+        matches!(event, EventMsg::TurnComplete(_)).then_some(())
+    })
+    .await;
+
+    let request = request.single_request();
+    assert_eq!(request.message_input_texts("user"), vec!["<external_api>"]);
+
+    Ok(())
+}
+
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn additional_context_trust_controls_message_role() -> Result<()> {
+    skip_if_no_network!(Ok(()));
+
+    let server = start_mock_server().await;
+    let request = mount_sse_once(
+        &server,
+        sse(vec![ev_response_created("resp-1"), ev_completed("resp-1")]),
+    )
+    .await;
+    let test = test_codex()
+        .with_config(|config| config.include_environment_context = false)
+        .build(&server)
+        .await?;
+
+    test.codex
+        .submit(Op::UserInput {
+            environments: None,
+            items: vec![UserInput::Text {
+                text: "inspect context".to_string(),
+                text_elements: Vec::new(),
+            }],
+            final_output_json_schema: None,
+            responsesapi_client_metadata: None,
+            additional_context: BTreeMap::from([
+                (
+                    "browser_info".to_string(),
+                    AdditionalContextEntry {
+                        value: "tab one".to_string(),
+                        kind: AdditionalContextKind::Untrusted,
+                    },
+                ),
+                (
+                    "automation_info".to_string(),
+                    AdditionalContextEntry {
+                        value: "run one".to_string(),
+                        kind: AdditionalContextKind::Application,
+                    },
+                ),
+            ]),
+            thread_settings: Default::default(),
+        })
+        .await?;
+    wait_for_event_match(&test.codex, |event| {
+        matches!(event, EventMsg::TurnComplete(_)).then_some(())
+    })
+    .await;
+
+    let request = request.single_request();
+    let developer_context_texts = request
+        .message_input_texts("developer")
+        .into_iter()
+        .filter(|text| text.starts_with("<automation_info>"))
+        .collect::<Vec<_>>();
+    assert_eq!(
+        developer_context_texts,
+        vec!["<automation_info>run one</automation_info>"]
+    );
+    assert_eq!(
+        request.message_input_texts("user"),
+        vec![
+            "<external_browser_info>tab one</external_browser_info>",
+            "inspect context",
+        ]
+    );
+
+    Ok(())
+}
+
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn additional_context_is_deduplicated_between_turns_while_retained() -> Result<()> {
+    skip_if_no_network!(Ok(()));
+
+    let server = start_mock_server().await;
+    let first_request = mount_sse_once(
+        &server,
+        sse(vec![ev_response_created("resp-1"), ev_completed("resp-1")]),
+    )
+    .await;
+    let second_request = mount_sse_once(
+        &server,
+        sse(vec![ev_response_created("resp-2"), ev_completed("resp-2")]),
+    )
+    .await;
+    let test = test_codex()
+        .with_config(|config| config.include_environment_context = false)
+        .build(&server)
+        .await?;
+    let additional_context = BTreeMap::from([(
+        "browser_info".to_string(),
+        AdditionalContextEntry {
+            value: "same tab".to_string(),
+            kind: AdditionalContextKind::Untrusted,
+        },
+    )]);
+
+    test.codex
+        .submit(Op::UserInput {
+            environments: None,
+            items: vec![UserInput::Text {
+                text: "first turn".to_string(),
+                text_elements: Vec::new(),
+            }],
+            final_output_json_schema: None,
+            responsesapi_client_metadata: None,
+            additional_context: additional_context.clone(),
+            thread_settings: Default::default(),
+        })
+        .await?;
+    wait_for_event_match(&test.codex, |event| {
+        matches!(event, EventMsg::TurnComplete(_)).then_some(())
+    })
+    .await;
+
+    test.codex
+        .submit(Op::UserInput {
+            environments: None,
+            items: vec![UserInput::Text {
+                text: "second turn".to_string(),
+                text_elements: Vec::new(),
+            }],
+            final_output_json_schema: None,
+            responsesapi_client_metadata: None,
+            additional_context,
+            thread_settings: Default::default(),
+        })
+        .await?;
+    wait_for_event_match(&test.codex, |event| {
+        matches!(event, EventMsg::TurnComplete(_)).then_some(())
+    })
+    .await;
+
+    assert_eq!(
+        first_request.single_request().message_input_texts("user"),
+        vec![
+            "<external_browser_info>same tab</external_browser_info>",
+            "first turn",
+        ]
+    );
+    assert_eq!(
+        second_request.single_request().message_input_texts("user"),
+        vec![
+            "<external_browser_info>same tab</external_browser_info>",
+            "first turn",
+            "second turn",
+        ]
+    );
+
+    Ok(())
+}
+
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn additional_context_removes_one_value_while_adding_another() -> Result<()> {
+    skip_if_no_network!(Ok(()));
+
+    let server = start_mock_server().await;
+    let first_request = mount_sse_once(
+        &server,
+        sse(vec![ev_response_created("resp-1"), ev_completed("resp-1")]),
+    )
+    .await;
+    let second_request = mount_sse_once(
+        &server,
+        sse(vec![ev_response_created("resp-2"), ev_completed("resp-2")]),
+    )
+    .await;
+    let third_request = mount_sse_once(
+        &server,
+        sse(vec![ev_response_created("resp-3"), ev_completed("resp-3")]),
+    )
+    .await;
+    let test = test_codex()
+        .with_config(|config| config.include_environment_context = false)
+        .build(&server)
+        .await?;
+
+    test.codex
+        .submit(Op::UserInput {
+            environments: None,
+            items: vec![UserInput::Text {
+                text: "first turn".to_string(),
+                text_elements: Vec::new(),
+            }],
+            final_output_json_schema: None,
+            responsesapi_client_metadata: None,
+            additional_context: BTreeMap::from([
+                (
+                    "automation_info".to_string(),
+                    AdditionalContextEntry {
+                        value: "run one".to_string(),
+                        kind: AdditionalContextKind::Untrusted,
+                    },
+                ),
+                (
+                    "browser_info".to_string(),
+                    AdditionalContextEntry {
+                        value: "tab one".to_string(),
+                        kind: AdditionalContextKind::Untrusted,
+                    },
+                ),
+            ]),
+            thread_settings: Default::default(),
+        })
+        .await?;
+    wait_for_event_match(&test.codex, |event| {
+        matches!(event, EventMsg::TurnComplete(_)).then_some(())
+    })
+    .await;
+
+    test.codex
+        .submit(Op::UserInput {
+            environments: None,
+            items: vec![UserInput::Text {
+                text: "second turn".to_string(),
+                text_elements: Vec::new(),
+            }],
+            final_output_json_schema: None,
+            responsesapi_client_metadata: None,
+            additional_context: BTreeMap::from([
+                (
+                    "automation_info".to_string(),
+                    AdditionalContextEntry {
+                        value: "run one".to_string(),
+                        kind: AdditionalContextKind::Untrusted,
+                    },
+                ),
+                (
+                    "terminal_info".to_string(),
+                    AdditionalContextEntry {
+                        value: "pty one".to_string(),
+                        kind: AdditionalContextKind::Untrusted,
+                    },
+                ),
+            ]),
+            thread_settings: Default::default(),
+        })
+        .await?;
+    wait_for_event_match(&test.codex, |event| {
+        matches!(event, EventMsg::TurnComplete(_)).then_some(())
+    })
+    .await;
+
+    test.codex
+        .submit(Op::UserInput {
+            environments: None,
+            items: vec![UserInput::Text {
+                text: "third turn".to_string(),
+                text_elements: Vec::new(),
+            }],
+            final_output_json_schema: None,
+            responsesapi_client_metadata: None,
+            additional_context: BTreeMap::from([
+                (
+                    "automation_info".to_string(),
+                    AdditionalContextEntry {
+                        value: "run one".to_string(),
+                        kind: AdditionalContextKind::Untrusted,
+                    },
+                ),
+                (
+                    "browser_info".to_string(),
+                    AdditionalContextEntry {
+                        value: "tab one".to_string(),
+                        kind: AdditionalContextKind::Untrusted,
+                    },
+                ),
+                (
+                    "terminal_info".to_string(),
+                    AdditionalContextEntry {
+                        value: "pty one".to_string(),
+                        kind: AdditionalContextKind::Untrusted,
+                    },
+                ),
+            ]),
+            thread_settings: Default::default(),
+        })
+        .await?;
+    wait_for_event_match(&test.codex, |event| {
+        matches!(event, EventMsg::TurnComplete(_)).then_some(())
+    })
+    .await;
+
+    assert_eq!(
+        first_request.single_request().message_input_texts("user"),
+        vec![
+            "<external_automation_info>run one</external_automation_info>",
+            "<external_browser_info>tab one</external_browser_info>",
+            "first turn",
+        ]
+    );
+    assert_eq!(
+        second_request.single_request().message_input_texts("user"),
+        vec![
+            "<external_automation_info>run one</external_automation_info>",
+            "<external_browser_info>tab one</external_browser_info>",
+            "first turn",
+            "<external_terminal_info>pty one</external_terminal_info>",
+            "second turn",
+        ]
+    );
+    assert_eq!(
+        third_request.single_request().message_input_texts("user"),
+        vec![
+            "<external_automation_info>run one</external_automation_info>",
+            "<external_browser_info>tab one</external_browser_info>",
+            "first turn",
+            "<external_terminal_info>pty one</external_terminal_info>",
+            "second turn",
+            "<external_browser_info>tab one</external_browser_info>",
+            "third turn",
+        ]
+    );
+
+    Ok(())
+}
+
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn additional_context_values_are_truncated_before_model_input() -> Result<()> {
+    skip_if_no_network!(Ok(()));
+
+    const MAX_EXPECTED_EXTERNAL_CONTEXT_TEXT_BYTES: usize = 5 * 1024;
+
+    let server = start_mock_server().await;
+    let request = mount_sse_once(
+        &server,
+        sse(vec![ev_response_created("resp-1"), ev_completed("resp-1")]),
+    )
+    .await;
+    let test = test_codex()
+        .with_config(|config| config.include_environment_context = false)
+        .build(&server)
+        .await?;
+    let long_browser_value = format!("browser-head-{}browser-tail", "b".repeat(40_000));
+    let long_automation_value = format!("automation-head-{}automation-tail", "a".repeat(40_000));
+    let untruncated_browser_fragment =
+        format!("<external_browser_info>{long_browser_value}</external_browser_info>");
+    let untruncated_automation_fragment =
+        format!("<automation_info>{long_automation_value}</automation_info>");
+
+    test.codex
+        .submit(Op::UserInput {
+            environments: None,
+            items: vec![UserInput::Text {
+                text: "summarize context".to_string(),
+                text_elements: Vec::new(),
+            }],
+            final_output_json_schema: None,
+            responsesapi_client_metadata: None,
+            additional_context: BTreeMap::from([
+                (
+                    "automation_info".to_string(),
+                    AdditionalContextEntry {
+                        value: long_automation_value.clone(),
+                        kind: AdditionalContextKind::Application,
+                    },
+                ),
+                (
+                    "browser_info".to_string(),
+                    AdditionalContextEntry {
+                        value: long_browser_value.clone(),
+                        kind: AdditionalContextKind::Untrusted,
+                    },
+                ),
+            ]),
+            thread_settings: Default::default(),
+        })
+        .await?;
+    wait_for_event_match(&test.codex, |event| {
+        matches!(event, EventMsg::TurnComplete(_)).then_some(())
+    })
+    .await;
+
+    let request = request.single_request();
+    let developer_texts = request
+        .message_input_texts("developer")
+        .into_iter()
+        .filter(|text| text.starts_with("<automation_info>"))
+        .collect::<Vec<_>>();
+    let [automation_text] = developer_texts.as_slice() else {
+        panic!("expected application additional context, got {developer_texts:?}");
+    };
+    assert!(automation_text.starts_with(&format!(
+        "<automation_info>automation-head-{}",
+        "a".repeat(1024)
+    )));
+    assert!(automation_text.contains("tokens truncated"));
+    assert!(automation_text.ends_with("automation-tail</automation_info>"));
+    assert!(automation_text.len() < untruncated_automation_fragment.len());
+    assert!(
+        automation_text.len() <= MAX_EXPECTED_EXTERNAL_CONTEXT_TEXT_BYTES,
+        "application additional context was not capped before model input: {} bytes",
+        automation_text.len()
+    );
+
+    let user_texts = request.message_input_texts("user");
+    let [external_text, user_text] = user_texts.as_slice() else {
+        panic!("expected external context plus user input, got {user_texts:?}");
+    };
+    assert_eq!(user_text, "summarize context");
+    assert!(external_text.starts_with(&format!(
+        "<external_browser_info>browser-head-{}",
+        "b".repeat(1024)
+    )));
+    assert!(external_text.contains("tokens truncated"));
+    assert!(external_text.ends_with("browser-tail</external_browser_info>"));
+    assert!(external_text.len() < untruncated_browser_fragment.len());
+    assert!(
+        external_text.len() <= MAX_EXPECTED_EXTERNAL_CONTEXT_TEXT_BYTES,
+        "untrusted additional context was not capped before model input: {} bytes",
+        external_text.len()
+    );
+
+    Ok(())
+}

codex-rs/core/tests/suite/apply_patch_cli.rs

@@ -91,6 +91,7 @@ async fn submit_without_wait_with_turn_permissions(
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(harness.cwd().to_path_buf()),
                 approval_policy: Some(AskForApproval::Never),

codex-rs/core/tests/suite/approvals.rs

@@ -653,6 +653,7 @@ async fn submit_turn(
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(test.cwd.path().to_path_buf()),
                 approval_policy: Some(approval_policy),
@@ -2598,6 +2599,7 @@ async fn matched_prefix_rule_runs_unsandboxed_under_zsh_fork() -> Result<()> {
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(test.cwd.path().to_path_buf()),
                 approval_policy: Some(approval_policy),

codex-rs/core/tests/suite/client.rs

@@ -392,6 +392,7 @@ async fn resume_includes_initial_messages_and_sends_prior_items() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -758,6 +759,7 @@ async fn includes_session_id_thread_id_and_model_headers_in_request() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -969,6 +971,7 @@ async fn includes_base_instructions_override_in_request() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -1026,6 +1029,7 @@ async fn chatgpt_auth_sends_correct_request() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -1150,6 +1154,7 @@ async fn prefers_apikey_when_config_prefers_apikey_even_with_chatgpt_tokens() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -1189,6 +1194,7 @@ async fn includes_user_instructions_message_in_request() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -1277,6 +1283,7 @@ async fn includes_apps_guidance_as_developer_message_for_chatgpt_auth() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -1340,6 +1347,7 @@ async fn omits_apps_guidance_for_api_key_auth_even_when_feature_enabled() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -1399,6 +1407,7 @@ async fn omits_apps_guidance_when_configured_off() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -1441,6 +1450,7 @@ async fn omits_environment_context_when_configured_off() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -1498,6 +1508,7 @@ async fn skills_append_to_developer_message() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -1581,6 +1592,7 @@ async fn skills_use_aliases_in_developer_message_under_budget_pressure() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -1642,6 +1654,7 @@ async fn includes_configured_effort_in_request() -> anyhow::Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -1684,6 +1697,7 @@ async fn includes_no_effort_in_request() -> anyhow::Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -1727,6 +1741,7 @@ async fn includes_default_reasoning_effort_in_request_when_defined_by_model_info
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -1778,6 +1793,7 @@ async fn user_turn_collaboration_mode_overrides_model_and_effort() -> anyhow::Re
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(config.cwd.to_path_buf()),
                 approval_policy: Some(config.permissions.approval_policy.value()),
@@ -1834,6 +1850,7 @@ async fn configured_reasoning_summary_is_sent() -> anyhow::Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -1899,6 +1916,7 @@ async fn user_turn_explicit_reasoning_summary_overrides_model_catalog_default()
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(config.cwd.to_path_buf()),
                 approval_policy: Some(config.permissions.approval_policy.value()),
@@ -1959,6 +1977,7 @@ async fn reasoning_summary_is_omitted_when_disabled() -> anyhow::Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -2018,6 +2037,7 @@ async fn reasoning_summary_none_overrides_model_catalog_default() -> anyhow::Res
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -2057,6 +2077,7 @@ async fn includes_default_verbosity_in_request() -> anyhow::Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -2105,6 +2126,7 @@ async fn configured_verbosity_not_sent_for_models_without_support() -> anyhow::R
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -2152,6 +2174,7 @@ async fn configured_verbosity_is_sent() -> anyhow::Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -2204,6 +2227,7 @@ async fn includes_developer_instructions_message_in_request() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -2500,6 +2524,7 @@ async fn token_count_includes_rate_limits_snapshot() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -2639,6 +2664,7 @@ async fn usage_limit_error_emits_rate_limit_event() -> anyhow::Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -2716,6 +2742,7 @@ async fn context_window_error_sets_total_tokens_to_model_window() -> anyhow::Res
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -2731,6 +2758,7 @@ async fn context_window_error_sets_total_tokens_to_model_window() -> anyhow::Res
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -2816,6 +2844,7 @@ async fn incomplete_response_emits_content_filter_error_message() -> anyhow::Res
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -2927,6 +2956,7 @@ async fn azure_overrides_assign_properties_used_for_responses_url() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -3016,6 +3046,7 @@ async fn env_var_overrides_loaded_auth() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -3073,6 +3104,7 @@ async fn history_dedupes_streamed_and_final_messages_across_turns() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -3089,6 +3121,7 @@ async fn history_dedupes_streamed_and_final_messages_across_turns() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -3105,6 +3138,7 @@ async fn history_dedupes_streamed_and_final_messages_across_turns() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await

codex-rs/core/tests/suite/client_websockets.rs

@@ -1319,6 +1319,7 @@ async fn responses_websocket_usage_limit_error_emits_rate_limit_event() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -1408,6 +1409,7 @@ async fn responses_websocket_invalid_request_error_with_status_is_forwarded() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await

codex-rs/core/tests/suite/code_mode.rs

@@ -2991,6 +2991,7 @@ text(
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(cwd),
                 approval_policy: Some(AskForApproval::Never),

codex-rs/core/tests/suite/collaboration_instructions.rs

@@ -79,6 +79,7 @@ async fn no_collaboration_instructions_by_default() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -133,6 +134,7 @@ async fn user_input_includes_collaboration_instructions_after_override() -> Resu
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -170,6 +172,7 @@ async fn collaboration_instructions_added_on_user_turn() -> Result<()> {
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(test.config.cwd.to_path_buf()),
                 approval_policy: Some(test.config.permissions.approval_policy.value()),
@@ -220,6 +223,7 @@ async fn collaboration_instructions_omitted_when_disabled() -> Result<()> {
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(test.config.cwd.to_path_buf()),
                 approval_policy: Some(test.config.permissions.approval_policy.value()),
@@ -279,6 +283,7 @@ async fn override_then_next_turn_uses_updated_collaboration_instructions() -> Re
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -327,6 +332,7 @@ async fn user_turn_overrides_collaboration_instructions_after_override() -> Resu
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(test.config.cwd.to_path_buf()),
                 approval_policy: Some(test.config.permissions.approval_policy.value()),
@@ -391,6 +397,7 @@ async fn collaboration_mode_update_emits_new_instruction_message() -> Result<()>
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -414,6 +421,7 @@ async fn collaboration_mode_update_emits_new_instruction_message() -> Result<()>
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -466,6 +474,7 @@ async fn collaboration_mode_update_noop_does_not_append() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -489,6 +498,7 @@ async fn collaboration_mode_update_noop_does_not_append() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -543,6 +553,7 @@ async fn collaboration_mode_update_emits_new_instruction_message_when_mode_chang
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -569,6 +580,7 @@ async fn collaboration_mode_update_emits_new_instruction_message_when_mode_chang
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -624,6 +636,7 @@ async fn collaboration_mode_update_noop_does_not_append_when_mode_is_unchanged()
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -650,6 +663,7 @@ async fn collaboration_mode_update_noop_does_not_append_when_mode_is_unchanged()
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -708,6 +722,7 @@ async fn resume_replays_collaboration_instructions() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -724,6 +739,7 @@ async fn resume_replays_collaboration_instructions() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -776,6 +792,7 @@ async fn empty_collaboration_instructions_are_ignored() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;

codex-rs/core/tests/suite/compact.rs

@@ -97,6 +97,7 @@ fn disabled_permission_user_turn(text: impl Into<String>, cwd: PathBuf, model: S
         environments: None,
         final_output_json_schema: None,
         responsesapi_client_metadata: None,
+        additional_context: Default::default(),
         thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
             cwd: Some(cwd),
             approval_policy: Some(AskForApproval::Never),
@@ -408,6 +409,7 @@ async fn summarize_context_three_requests_and_instructions() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -433,6 +435,7 @@ async fn summarize_context_three_requests_and_instructions() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -610,6 +613,7 @@ async fn manual_pre_compact_block_decision_does_not_block_compaction() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -683,6 +687,7 @@ async fn compact_hooks_respect_matchers_and_post_runs_after_compaction() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -753,6 +758,7 @@ async fn manual_compact_uses_custom_prompt() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -900,6 +906,7 @@ async fn manual_compact_emits_context_compaction_items() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -1066,6 +1073,7 @@ async fn multiple_auto_compact_per_task_runs_after_token_limit_hit() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -1538,6 +1546,7 @@ async fn auto_compact_runs_after_token_limit_hit() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -1554,6 +1563,7 @@ async fn auto_compact_runs_after_token_limit_hit() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -1570,6 +1580,7 @@ async fn auto_compact_runs_after_token_limit_hit() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -1741,6 +1752,7 @@ async fn auto_compact_emits_context_compaction_items() {
                 }],
                 final_output_json_schema: None,
                 responsesapi_client_metadata: None,
+                additional_context: Default::default(),
                 thread_settings: Default::default(),
             })
             .await
@@ -1822,6 +1834,7 @@ async fn auto_compact_starts_after_turn_started() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -1837,6 +1850,7 @@ async fn auto_compact_starts_after_turn_started() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -1852,6 +1866,7 @@ async fn auto_compact_starts_after_turn_started() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -2380,6 +2395,7 @@ async fn auto_compact_persists_rollout_entries() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -2395,6 +2411,7 @@ async fn auto_compact_persists_rollout_entries() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -2410,6 +2427,7 @@ async fn auto_compact_persists_rollout_entries() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -2499,6 +2517,7 @@ async fn manual_compact_retries_after_context_window_error() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -2603,6 +2622,7 @@ async fn manual_compact_non_context_failure_retries_then_emits_task_error() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -2698,6 +2718,7 @@ async fn manual_compact_twice_preserves_latest_user_messages() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -2716,6 +2737,7 @@ async fn manual_compact_twice_preserves_latest_user_messages() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -2734,6 +2756,7 @@ async fn manual_compact_twice_preserves_latest_user_messages() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -2898,6 +2921,7 @@ async fn auto_compact_allows_multiple_attempts_when_interleaved_with_other_turn_
                 }],
                 final_output_json_schema: None,
                 responsesapi_client_metadata: None,
+                additional_context: Default::default(),
                 thread_settings: Default::default(),
             })
             .await
@@ -3003,6 +3027,7 @@ async fn snapshot_request_shape_mid_turn_continuation_compaction() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -3434,6 +3459,7 @@ async fn auto_compact_counts_encrypted_reasoning_before_last_user() {
                 }],
                 final_output_json_schema: None,
                 responsesapi_client_metadata: None,
+                additional_context: Default::default(),
                 thread_settings: Default::default(),
             })
             .await
@@ -3553,6 +3579,7 @@ async fn auto_compact_runs_when_reasoning_header_clears_between_turns() {
                 }],
                 final_output_json_schema: None,
                 responsesapi_client_metadata: None,
+                additional_context: Default::default(),
                 thread_settings: Default::default(),
             })
             .await
@@ -3615,6 +3642,7 @@ async fn snapshot_request_shape_pre_turn_compaction_including_incoming_user_mess
                 }],
                 final_output_json_schema: None,
                 responsesapi_client_metadata: None,
+                additional_context: Default::default(),
                 thread_settings: Default::default(),
             })
             .await
@@ -3647,6 +3675,7 @@ async fn snapshot_request_shape_pre_turn_compaction_including_incoming_user_mess
             ],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -3836,6 +3865,7 @@ async fn snapshot_request_shape_pre_turn_compaction_context_window_exceeded() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -3851,6 +3881,7 @@ async fn snapshot_request_shape_pre_turn_compaction_context_window_exceeded() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -3924,6 +3955,7 @@ async fn snapshot_request_shape_manual_compact_without_previous_user_messages()
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await

codex-rs/core/tests/suite/compact_remote.rs

@@ -326,6 +326,7 @@ async fn remote_compact_replaces_history_for_followups() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -343,6 +344,7 @@ async fn remote_compact_replaces_history_for_followups() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -518,6 +520,7 @@ async fn assert_remote_manual_compact_request_parity(
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -538,6 +541,7 @@ async fn assert_remote_manual_compact_request_parity(
             ],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -552,6 +556,7 @@ async fn assert_remote_manual_compact_request_parity(
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -572,6 +577,7 @@ async fn assert_remote_manual_compact_request_parity(
             ],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -586,6 +592,7 @@ async fn assert_remote_manual_compact_request_parity(
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -754,6 +761,7 @@ async fn remote_compact_v2_reuses_compaction_trigger_for_followups() -> Result<(
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -771,6 +779,7 @@ async fn remote_compact_v2_reuses_compaction_trigger_for_followups() -> Result<(
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -874,6 +883,7 @@ async fn remote_compact_v2_retries_failures_with_stream_retry_budget() -> Result
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -891,6 +901,7 @@ async fn remote_compact_v2_retries_failures_with_stream_retry_budget() -> Result
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -977,6 +988,7 @@ async fn remote_compact_v2_accepts_additional_output_items_before_compaction() -
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -994,6 +1006,7 @@ async fn remote_compact_v2_accepts_additional_output_items_before_compaction() -
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -1085,6 +1098,7 @@ async fn remote_compact_filters_deferred_dynamic_tools() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -1157,6 +1171,7 @@ async fn remote_compact_runs_automatically() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -1238,6 +1253,7 @@ async fn remote_compact_trims_function_call_history_to_fit_context_window() -> R
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -1252,6 +1268,7 @@ async fn remote_compact_trims_function_call_history_to_fit_context_window() -> R
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -1370,6 +1387,7 @@ async fn auto_remote_compact_trims_function_call_history_to_fit_context_window()
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -1384,6 +1402,7 @@ async fn auto_remote_compact_trims_function_call_history_to_fit_context_window()
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -1404,6 +1423,7 @@ async fn auto_remote_compact_trims_function_call_history_to_fit_context_window()
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -1504,6 +1524,7 @@ async fn auto_remote_compact_failure_stops_agent_loop() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -1518,6 +1539,7 @@ async fn auto_remote_compact_failure_stops_agent_loop() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -1612,6 +1634,7 @@ async fn remote_compact_trim_estimate_uses_session_base_instructions() -> Result
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -1629,6 +1652,7 @@ async fn remote_compact_trim_estimate_uses_session_base_instructions() -> Result
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -1720,6 +1744,7 @@ async fn remote_compact_trim_estimate_uses_session_base_instructions() -> Result
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -1737,6 +1762,7 @@ async fn remote_compact_trim_estimate_uses_session_base_instructions() -> Result
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -1808,6 +1834,7 @@ async fn remote_manual_compact_emits_context_compaction_items() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -1889,6 +1916,7 @@ async fn remote_manual_compact_failure_emits_task_error_event() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -1973,6 +2001,7 @@ async fn remote_compact_persists_replacement_history_in_rollout() -> Result<()>
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -2116,6 +2145,7 @@ async fn remote_compact_and_resume_refresh_stale_developer_instructions() -> Res
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -2134,6 +2164,7 @@ async fn remote_compact_and_resume_refresh_stale_developer_instructions() -> Res
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -2159,6 +2190,7 @@ async fn remote_compact_and_resume_refresh_stale_developer_instructions() -> Res
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -2255,6 +2287,7 @@ async fn remote_compact_refreshes_stale_developer_instructions_without_resume()
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -2272,6 +2305,7 @@ async fn remote_compact_refreshes_stale_developer_instructions_without_resume()
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -2344,6 +2378,7 @@ async fn snapshot_request_shape_remote_pre_turn_compaction_restates_realtime_sta
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -2358,6 +2393,7 @@ async fn snapshot_request_shape_remote_pre_turn_compaction_restates_realtime_sta
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -2425,6 +2461,7 @@ async fn remote_request_uses_custom_experimental_realtime_start_instructions() -
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -2486,6 +2523,7 @@ async fn snapshot_request_shape_remote_pre_turn_compaction_restates_realtime_end
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -2502,6 +2540,7 @@ async fn snapshot_request_shape_remote_pre_turn_compaction_restates_realtime_end
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -2577,6 +2616,7 @@ async fn snapshot_request_shape_remote_manual_compact_restates_realtime_start()
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -2594,6 +2634,7 @@ async fn snapshot_request_shape_remote_manual_compact_restates_realtime_start()
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -2677,6 +2718,7 @@ async fn snapshot_request_shape_remote_mid_turn_compaction_does_not_restate_real
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -2693,6 +2735,7 @@ async fn snapshot_request_shape_remote_mid_turn_compaction_does_not_restate_real
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -2784,6 +2827,7 @@ async fn snapshot_request_shape_remote_compact_resume_restates_realtime_end() ->
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -2814,6 +2858,7 @@ async fn snapshot_request_shape_remote_compact_resume_restates_realtime_end() ->
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -2903,6 +2948,7 @@ async fn snapshot_request_shape_remote_pre_turn_compaction_including_incoming_us
                 }],
                 final_output_json_schema: None,
                 responsesapi_client_metadata: None,
+                additional_context: Default::default(),
                 thread_settings: Default::default(),
             })
             .await?;
@@ -2990,6 +3036,7 @@ async fn snapshot_request_shape_remote_pre_turn_compaction_strips_incoming_model
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -3012,6 +3059,7 @@ async fn snapshot_request_shape_remote_pre_turn_compaction_strips_incoming_model
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -3131,6 +3179,7 @@ async fn snapshot_request_shape_remote_pre_turn_compaction_context_window_exceed
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -3145,6 +3194,7 @@ async fn snapshot_request_shape_remote_pre_turn_compaction_context_window_exceed
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -3230,6 +3280,7 @@ async fn snapshot_request_shape_remote_mid_turn_continuation_compaction() -> Res
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -3308,6 +3359,7 @@ async fn snapshot_request_shape_remote_mid_turn_compaction_summary_only_reinject
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -3394,6 +3446,7 @@ async fn snapshot_request_shape_remote_mid_turn_compaction_multi_summary_reinjec
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -3411,6 +3464,7 @@ async fn snapshot_request_shape_remote_mid_turn_compaction_multi_summary_reinjec
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -3493,6 +3547,7 @@ async fn snapshot_request_shape_remote_manual_compact_without_previous_user_mess
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;

codex-rs/core/tests/suite/compact_remote_parity.rs

@@ -606,6 +606,7 @@ async fn submit_user_input(codex: &codex_core::CodexThread, items: Vec<UserInput
             items,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;

codex-rs/core/tests/suite/compact_resume_fork.rs

@@ -783,6 +783,7 @@ async fn user_turn(conversation: &Arc<CodexThread>, text: &str) {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await

codex-rs/core/tests/suite/exec_policy.rs

@@ -54,6 +54,7 @@ async fn submit_user_turn(
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(test.cwd_path().to_path_buf()),
                 approval_policy: Some(approval_policy),
@@ -141,6 +142,7 @@ async fn execpolicy_blocks_shell_invocation() -> Result<()> {
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(test.cwd_path().to_path_buf()),
                 approval_policy: Some(AskForApproval::Never),

codex-rs/core/tests/suite/fork_thread.rs

@@ -57,6 +57,7 @@ async fn fork_thread_twice_drops_to_first_message() {
                 }],
                 final_output_json_schema: None,
                 responsesapi_client_metadata: None,
+                additional_context: Default::default(),
                 thread_settings: Default::default(),
             })
             .await
@@ -181,6 +182,7 @@ async fn fork_thread_from_history_does_not_require_source_rollout_path() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await

codex-rs/core/tests/suite/hooks.rs

@@ -1850,6 +1850,7 @@ async fn blocked_queued_prompt_does_not_strand_earlier_accepted_prompt() -> Resu
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -1869,6 +1870,7 @@ async fn blocked_queued_prompt_does_not_strand_earlier_accepted_prompt() -> Resu
                 }],
                 final_output_json_schema: None,
                 responsesapi_client_metadata: None,
+                additional_context: Default::default(),
                 thread_settings: Default::default(),
             })
             .await?;

codex-rs/core/tests/suite/image_rollout.rs

@@ -127,6 +127,7 @@ async fn copy_paste_local_image_persists_rollout_request_shape() -> anyhow::Resu
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(cwd.path().to_path_buf()),
                 approval_policy: Some(AskForApproval::Never),
@@ -223,6 +224,7 @@ async fn drag_drop_image_persists_rollout_request_shape() -> anyhow::Result<()>
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(cwd.path().to_path_buf()),
                 approval_policy: Some(AskForApproval::Never),

codex-rs/core/tests/suite/items.rs

@@ -58,6 +58,7 @@ fn disabled_plan_turn(
         environments: None,
         final_output_json_schema: None,
         responsesapi_client_metadata: None,
+        additional_context: Default::default(),
         thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
             cwd: Some(cwd),
             approval_policy: Some(AskForApproval::Never),
@@ -119,6 +120,7 @@ async fn user_message_item_is_emitted() -> anyhow::Result<()> {
             items: vec![expected_input.clone()],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -178,6 +180,7 @@ async fn assistant_message_item_is_emitted() -> anyhow::Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -239,6 +242,7 @@ async fn reasoning_item_is_emitted() -> anyhow::Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -301,6 +305,7 @@ async fn web_search_item_is_emitted() -> anyhow::Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -381,6 +386,7 @@ async fn image_generation_call_event_is_emitted() -> anyhow::Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -468,6 +474,7 @@ async fn image_generation_call_event_is_emitted_when_image_save_fails() -> anyho
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -524,6 +531,7 @@ async fn agent_message_content_delta_has_item_metadata() -> anyhow::Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -1108,6 +1116,7 @@ async fn reasoning_content_delta_has_item_metadata() -> anyhow::Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -1163,6 +1172,7 @@ async fn reasoning_raw_content_delta_respects_flag() -> anyhow::Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;

codex-rs/core/tests/suite/json_result.rs

@@ -83,6 +83,7 @@ async fn codex_returns_json_result(model: String) -> anyhow::Result<()> {
             environments: None,
             final_output_json_schema: Some(serde_json::from_str(SCHEMA)?),
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(cwd.path().to_path_buf()),
                 approval_policy: Some(AskForApproval::Never),

codex-rs/core/tests/suite/mcp_turn_metadata.rs

@@ -76,6 +76,7 @@ async fn submit_user_turn(
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(test.cwd.path().to_path_buf()),
                 approval_policy: Some(approval_policy),

codex-rs/core/tests/suite/mod.rs

@@ -29,6 +29,7 @@ pub static CODEX_ALIASES_TEMP_DIR: Option<TestBinaryDispatchGuard> = {
 
 #[cfg(not(target_os = "windows"))]
 mod abort_tasks;
+mod additional_context;
 mod agent_jobs;
 mod agent_websocket;
 mod agents_md;

codex-rs/core/tests/suite/model_switching.rs

@@ -48,6 +48,7 @@ fn read_only_user_turn(test: &TestCodex, items: Vec<UserInput>, model: String) -
         environments: None,
         final_output_json_schema: None,
         responsesapi_client_metadata: None,
+        additional_context: Default::default(),
         thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
             cwd: Some(test.cwd_path().to_path_buf()),
             approval_policy: Some(AskForApproval::Never),

codex-rs/core/tests/suite/model_visible_layout.rs

@@ -125,6 +125,7 @@ async fn snapshot_model_visible_layout_turn_overrides() -> Result<()> {
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(first_turn_cwd),
                 approval_policy: Some(AskForApproval::Never),
@@ -160,6 +161,7 @@ async fn snapshot_model_visible_layout_turn_overrides() -> Result<()> {
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(preturn_context_diff_cwd),
                 approval_policy: Some(AskForApproval::OnRequest),
@@ -249,6 +251,7 @@ async fn snapshot_model_visible_layout_cwd_change_does_not_refresh_agents() -> R
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(cwd_one.clone()),
                 approval_policy: Some(AskForApproval::Never),
@@ -282,6 +285,7 @@ async fn snapshot_model_visible_layout_cwd_change_does_not_refresh_agents() -> R
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(cwd_two),
                 approval_policy: Some(AskForApproval::Never),
@@ -365,6 +369,7 @@ async fn snapshot_model_visible_layout_resume_with_personality_change() -> Resul
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -406,6 +411,7 @@ async fn snapshot_model_visible_layout_resume_with_personality_change() -> Resul
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(resume_override_cwd),
                 approval_policy: Some(AskForApproval::Never),
@@ -479,6 +485,7 @@ async fn snapshot_model_visible_layout_resume_override_matches_rollout_model() -
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -520,6 +527,7 @@ async fn snapshot_model_visible_layout_resume_override_matches_rollout_model() -
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;

codex-rs/core/tests/suite/models_cache_ttl.rs

@@ -100,6 +100,7 @@ async fn renews_cache_ttl_on_matching_models_etag() -> Result<()> {
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(test.cwd_path().to_path_buf()),
                 approval_policy: Some(codex_protocol::protocol::AskForApproval::Never),

codex-rs/core/tests/suite/models_etag_responses.rs

@@ -112,6 +112,7 @@ async fn refresh_models_on_models_etag_mismatch_and_avoid_duplicate_models_fetch
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(cwd_path),
                 approval_policy: Some(AskForApproval::Never),

codex-rs/core/tests/suite/otel.rs

@@ -122,6 +122,7 @@ async fn responses_api_emits_api_request_event() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -168,6 +169,7 @@ async fn process_sse_emits_tracing_for_output_item() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -214,6 +216,7 @@ async fn process_sse_emits_failed_event_on_parse_error() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -261,6 +264,7 @@ async fn process_sse_records_failed_event_when_stream_closes_without_completed()
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -328,6 +332,7 @@ async fn process_sse_failed_event_records_response_error_message() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -393,6 +398,7 @@ async fn process_sse_failed_event_logs_parse_error() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -445,6 +451,7 @@ async fn process_sse_failed_event_logs_missing_error() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -506,6 +513,7 @@ async fn process_sse_failed_event_logs_response_completed_parse_error() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -561,6 +569,7 @@ async fn process_sse_emits_completed_telemetry() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -640,6 +649,7 @@ async fn turn_and_completed_response_spans_record_token_usage() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -728,6 +738,7 @@ async fn handle_responses_span_records_response_kind_and_tool_name() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -822,6 +833,7 @@ async fn record_responses_sets_span_fields_for_response_events() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -911,6 +923,7 @@ async fn handle_response_item_records_tool_result_for_custom_tool_call() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -987,6 +1000,7 @@ async fn handle_response_item_records_tool_result_for_function_call() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -1064,6 +1078,7 @@ async fn handle_response_item_records_tool_result_for_shell_command_call() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -1173,6 +1188,7 @@ async fn handle_shell_command_autoapprove_from_config_records_tool_decision() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -1228,6 +1244,7 @@ async fn handle_shell_command_user_approved_records_tool_decision() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -1298,6 +1315,7 @@ async fn handle_shell_command_user_approved_for_session_records_tool_decision()
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -1368,6 +1386,7 @@ async fn handle_sandbox_error_user_approves_retry_records_tool_decision() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -1438,6 +1457,7 @@ async fn handle_shell_command_user_denies_records_tool_decision() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -1508,6 +1528,7 @@ async fn handle_sandbox_error_user_approves_for_session_records_tool_decision()
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -1579,6 +1600,7 @@ async fn handle_sandbox_error_user_denies_records_tool_decision() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await

codex-rs/core/tests/suite/pending_input.rs

@@ -103,6 +103,7 @@ async fn submit_user_input(codex: &CodexThread, text: &str) {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -121,6 +122,7 @@ async fn submit_danger_full_access_user_turn(test: &TestCodex, text: &str) {
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(test.config.cwd.to_path_buf()),
                 approval_policy: Some(AskForApproval::Never),
@@ -148,6 +150,7 @@ async fn steer_user_input(codex: &CodexThread, text: &str) {
                 text: text.to_string(),
                 text_elements: Vec::new(),
             }],
+            /*additional_context*/ Default::default(),
             /*expected_turn_id*/ None,
             /*responsesapi_client_metadata*/ None,
         )
@@ -291,6 +294,7 @@ async fn injected_user_input_triggers_follow_up_request_with_deltas() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -310,6 +314,7 @@ async fn injected_user_input_triggers_follow_up_request_with_deltas() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await

codex-rs/core/tests/suite/permissions_messages.rs

@@ -58,6 +58,7 @@ async fn permissions_message_sent_once_on_start() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -98,6 +99,7 @@ async fn permissions_message_added_on_override_change() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -121,6 +123,7 @@ async fn permissions_message_added_on_override_change() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -167,6 +170,7 @@ async fn permissions_message_not_added_when_no_change() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -181,6 +185,7 @@ async fn permissions_message_not_added_when_no_change() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -227,6 +232,7 @@ async fn permissions_message_omitted_when_disabled() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -250,6 +256,7 @@ async fn permissions_message_omitted_when_disabled() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -309,6 +316,7 @@ async fn resume_replays_permissions_messages() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -333,6 +341,7 @@ async fn resume_replays_permissions_messages() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -349,6 +358,7 @@ async fn resume_replays_permissions_messages() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -409,6 +419,7 @@ async fn resume_and_fork_append_permissions_messages() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -433,6 +444,7 @@ async fn resume_and_fork_append_permissions_messages() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -455,6 +467,7 @@ async fn resume_and_fork_append_permissions_messages() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -491,6 +504,7 @@ async fn resume_and_fork_append_permissions_messages() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -552,6 +566,7 @@ async fn permissions_message_includes_writable_roots() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;

codex-rs/core/tests/suite/personality.rs

@@ -68,6 +68,7 @@ fn read_only_text_turn_with_personality(
         environments: None,
         final_output_json_schema: None,
         responsesapi_client_metadata: None,
+        additional_context: Default::default(),
         thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
             cwd: Some(test.cwd_path().to_path_buf()),
             approval_policy: Some(approval_policy),

codex-rs/core/tests/suite/plugins.rs

@@ -227,6 +227,7 @@ async fn capability_sections_render_in_developer_message_in_order() -> Result<()
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -306,6 +307,7 @@ async fn explicit_plugin_mentions_inject_plugin_guidance() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -388,6 +390,7 @@ async fn explicit_plugin_mentions_track_plugin_used_analytics() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;

codex-rs/core/tests/suite/prompt_caching.rs

@@ -153,6 +153,7 @@ async fn prompt_tools_are_consistent_across_requests() -> anyhow::Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -167,6 +168,7 @@ async fn prompt_tools_are_consistent_across_requests() -> anyhow::Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -250,6 +252,7 @@ async fn gpt_5_tools_without_apply_patch_append_apply_patch_instructions() -> an
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -264,6 +267,7 @@ async fn gpt_5_tools_without_apply_patch_append_apply_patch_instructions() -> an
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -329,6 +333,7 @@ async fn prefixes_context_and_instructions_once_and_consistently_across_requests
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -343,6 +348,7 @@ async fn prefixes_context_and_instructions_once_and_consistently_across_requests
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -426,6 +432,7 @@ async fn overrides_turn_context_but_keeps_cached_prefix_and_key_constant() -> an
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -464,6 +471,7 @@ async fn overrides_turn_context_but_keeps_cached_prefix_and_key_constant() -> an
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -545,6 +553,7 @@ async fn override_before_first_turn_emits_environment_context() -> anyhow::Resul
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -699,6 +708,7 @@ async fn per_turn_overrides_keep_cached_prefix_and_key_constant() -> anyhow::Res
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -724,6 +734,7 @@ async fn per_turn_overrides_keep_cached_prefix_and_key_constant() -> anyhow::Res
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(new_cwd.path().to_path_buf()),
                 approval_policy: Some(AskForApproval::Never),
@@ -838,6 +849,7 @@ async fn send_user_turn_with_no_changes_does_not_send_environment_context() -> a
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(default_cwd.to_path_buf()),
                 approval_policy: Some(default_approval_policy),
@@ -866,6 +878,7 @@ async fn send_user_turn_with_no_changes_does_not_send_environment_context() -> a
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(default_cwd.to_path_buf()),
                 approval_policy: Some(default_approval_policy),
@@ -977,6 +990,7 @@ async fn send_user_turn_with_changes_sends_environment_context() -> anyhow::Resu
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(default_cwd.to_path_buf()),
                 approval_policy: Some(default_approval_policy),
@@ -1007,6 +1021,7 @@ async fn send_user_turn_with_changes_sends_environment_context() -> anyhow::Resu
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(default_cwd.to_path_buf()),
                 approval_policy: Some(AskForApproval::Never),

codex-rs/core/tests/suite/quota_exceeded.rs

@@ -48,6 +48,7 @@ async fn quota_exceeded_emits_single_error_event() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await

codex-rs/core/tests/suite/realtime_conversation.rs

@@ -2168,6 +2168,7 @@ async fn conversation_user_text_turn_is_sent_to_realtime_when_active() -> Result
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -2303,6 +2304,7 @@ async fn conversation_user_text_turn_is_capped_when_mirrored_to_realtime() -> Re
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -3499,6 +3501,7 @@ async fn inbound_handoff_request_steers_active_turn() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;

codex-rs/core/tests/suite/remote_env.rs

@@ -75,6 +75,7 @@ async fn submit_turn_with_approval_and_environments(
             environments: Some(environments),
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(test.cwd.path().to_path_buf()),
                 approval_policy: Some(AskForApproval::OnRequest),

codex-rs/core/tests/suite/remote_models.rs

@@ -160,6 +160,7 @@ async fn remote_models_config_context_window_override_clamps_to_max_context_wind
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -227,6 +228,7 @@ async fn remote_models_config_override_above_max_uses_max_context_window() -> Re
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -293,6 +295,7 @@ async fn remote_models_use_context_window_when_config_override_is_absent() -> Re
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -372,6 +375,7 @@ async fn remote_models_long_model_slug_is_sent_with_high_reasoning() -> Result<(
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -422,6 +426,7 @@ async fn namespaced_model_slug_uses_catalog_metadata_without_fallback_warning()
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -575,6 +580,7 @@ async fn remote_models_remote_model_uses_unified_exec() -> Result<()> {
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(cwd_path),
                 approval_policy: Some(AskForApproval::Never),
@@ -798,6 +804,7 @@ async fn remote_models_apply_remote_base_instructions() -> Result<()> {
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(cwd_path),
                 approval_policy: Some(AskForApproval::Never),

codex-rs/core/tests/suite/request_compression.rs

@@ -47,6 +47,7 @@ async fn request_body_is_zstd_compressed_for_codex_backend_when_enabled() -> any
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -97,6 +98,7 @@ async fn request_body_is_not_compressed_for_api_key_auth_even_when_enabled() ->
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;

codex-rs/core/tests/suite/request_permissions.rs

@@ -198,6 +198,7 @@ async fn submit_turn(
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(test.cwd.path().to_path_buf()),
                 approval_policy: Some(approval_policy),

codex-rs/core/tests/suite/request_permissions_tool.rs

@@ -150,6 +150,7 @@ async fn submit_turn(
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(test.cwd.path().to_path_buf()),
                 approval_policy: Some(approval_policy),

codex-rs/core/tests/suite/request_user_input.rs

@@ -144,6 +144,7 @@ async fn request_user_input_round_trip_for_mode(mode: ModeKind) -> anyhow::Resul
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(cwd.path().to_path_buf()),
                 approval_policy: Some(AskForApproval::Never),
@@ -287,6 +288,7 @@ async fn request_user_input_interrupt_emits_deferred_token_count() -> anyhow::Re
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(cwd.path().to_path_buf()),
                 approval_policy: Some(AskForApproval::Never),
@@ -391,6 +393,7 @@ where
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(cwd.path().to_path_buf()),
                 approval_policy: Some(AskForApproval::Never),

codex-rs/core/tests/suite/responses_api_proxy_headers.rs

@@ -143,6 +143,7 @@ async fn submit_turn_with_timeout(test: &TestCodex, prompt: &str) -> Result<()>
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(cwd),
                 approval_policy: Some(AskForApproval::OnRequest),

codex-rs/core/tests/suite/resume.rs

@@ -93,6 +93,7 @@ async fn resume_includes_initial_messages_from_rollout_events() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -179,6 +180,7 @@ async fn resume_includes_initial_messages_from_reasoning_events() -> Result<()>
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -269,6 +271,7 @@ async fn resume_switches_models_preserves_base_instructions() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -312,6 +315,7 @@ async fn resume_switches_models_preserves_base_instructions() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -330,6 +334,7 @@ async fn resume_switches_models_preserves_base_instructions() -> Result<()> {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -403,6 +408,7 @@ async fn resume_model_switch_is_not_duplicated_after_pre_turn_override() -> Resu
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -441,6 +447,7 @@ async fn resume_model_switch_is_not_duplicated_after_pre_turn_override() -> Resu
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;

codex-rs/core/tests/suite/review.rs

@@ -684,6 +684,7 @@ async fn review_history_surfaces_in_parent_session() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await

codex-rs/core/tests/suite/rmcp_client.rs

@@ -131,6 +131,7 @@ fn user_turn_with_permission_profile(
         environments: None,
         final_output_json_schema: None,
         responsesapi_client_metadata: None,
+        additional_context: Default::default(),
         thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
             cwd: Some(cwd),
             approval_policy: Some(AskForApproval::Never),

codex-rs/core/tests/suite/safety_check_downgrade.rs

@@ -45,6 +45,7 @@ fn disabled_text_turn(test: &TestCodex, text: &str) -> Op {
         environments: None,
         final_output_json_schema: None,
         responsesapi_client_metadata: None,
+        additional_context: Default::default(),
         thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
             cwd: Some(test.cwd_path().to_path_buf()),
             approval_policy: Some(AskForApproval::Never),

codex-rs/core/tests/suite/search_tool.rs

@@ -452,6 +452,7 @@ async fn tool_search_returns_deferred_tools_without_follow_up_tool_injection() -
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -865,6 +866,7 @@ async fn tool_search_returns_deferred_dynamic_tool_and_routes_follow_up_call() -
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -1173,6 +1175,7 @@ async fn tool_search_surfaced_mcp_tool_errors_are_returned_to_model() -> Result<
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;
@@ -1493,6 +1496,7 @@ async fn tool_search_matches_dynamic_tools_by_name_description_namespace_and_sch
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;

codex-rs/core/tests/suite/shell_snapshot.rs

@@ -167,6 +167,7 @@ async fn run_snapshot_command_with_options(
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(cwd),
                 approval_policy: Some(AskForApproval::Never),
@@ -267,6 +268,7 @@ async fn run_shell_command_snapshot_with_options(
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(cwd),
                 approval_policy: Some(AskForApproval::Never),
@@ -347,6 +349,7 @@ async fn run_tool_turn_on_harness(
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(cwd),
                 approval_policy: Some(AskForApproval::Never),
@@ -590,6 +593,7 @@ async fn shell_command_snapshot_still_intercepts_apply_patch() -> Result<()> {
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(cwd.clone()),
                 approval_policy: Some(AskForApproval::Never),

codex-rs/core/tests/suite/skill_approval.rs

@@ -54,6 +54,7 @@ async fn submit_turn_with_policies(
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(test.cwd_path().to_path_buf()),
                 approval_policy: Some(approval_policy),

codex-rs/core/tests/suite/skills.rs

@@ -88,6 +88,7 @@ async fn user_turn_includes_skill_instructions() -> Result<()> {
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(test.config.cwd.to_path_buf()),
                 approval_policy: Some(AskForApproval::Never),

codex-rs/core/tests/suite/snapshots/all__suite__additional_context__additional_context_simple_input.snap

@@ -0,0 +1,11 @@
+---
+source: core/tests/suite/additional_context.rs
+expression: "context_snapshot::format_labeled_requests_snapshot(\"additional context is inserted before the user turn input.\",\n&[(\"Request\", &request)], &additional_context_snapshot_options(),)"
+---
+Scenario: additional context is inserted before the user turn input.
+
+## Request
+00:message/developer:<PERMISSIONS_INSTRUCTIONS>
+01:message/developer:<automation_info>run one</automation_info>
+02:message/user:<external_browser_info>tab one</external_browser_info>
+03:message/user:inspect the active tab

codex-rs/core/tests/suite/sqlite_state.rs

@@ -413,6 +413,7 @@ async fn mcp_call_marks_thread_memory_mode_polluted_when_configured() -> Result<
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(cwd),
                 approval_policy: Some(AskForApproval::Never),

codex-rs/core/tests/suite/stream_error_allows_next_turn.rs

@@ -101,6 +101,7 @@ async fn continue_after_stream_error() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await
@@ -123,6 +124,7 @@ async fn continue_after_stream_error() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await

codex-rs/core/tests/suite/stream_no_completed.rs

@@ -83,6 +83,7 @@ async fn retries_on_early_close() {
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await

codex-rs/core/tests/suite/subagent_notifications.rs

@@ -771,6 +771,7 @@ async fn subagent_stop_replaces_stop_and_skips_internal_subagents() -> Result<()
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(test.config.cwd.to_path_buf()),
                 approval_policy: Some(AskForApproval::Never),

codex-rs/core/tests/suite/tool_harness.rs

@@ -110,6 +110,7 @@ async fn shell_command_tool_executes_command_and_streams_output() -> anyhow::Res
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(cwd_path),
                 approval_policy: Some(AskForApproval::Never),
@@ -191,6 +192,7 @@ async fn update_plan_tool_emits_plan_update_event() -> anyhow::Result<()> {
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(cwd_path),
                 approval_policy: Some(AskForApproval::Never),
@@ -282,6 +284,7 @@ async fn update_plan_tool_rejects_malformed_payload() -> anyhow::Result<()> {
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(cwd_path),
                 approval_policy: Some(AskForApproval::Never),
@@ -383,6 +386,7 @@ async fn apply_patch_tool_executes_and_emits_patch_events() -> anyhow::Result<()
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(cwd_path),
                 approval_policy: Some(AskForApproval::Never),
@@ -521,6 +525,7 @@ async fn apply_patch_reports_parse_diagnostics() -> anyhow::Result<()> {
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(cwd_path),
                 approval_policy: Some(AskForApproval::Never),

codex-rs/core/tests/suite/tool_parallelism.rs

@@ -45,6 +45,7 @@ async fn run_turn(test: &TestCodex, prompt: &str) -> anyhow::Result<()> {
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(test.cwd.path().to_path_buf()),
                 approval_policy: Some(AskForApproval::Never),
@@ -371,6 +372,7 @@ async fn shell_tools_start_before_response_completed_when_stream_delayed() -> an
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(test.cwd.path().to_path_buf()),
                 approval_policy: Some(AskForApproval::Never),

codex-rs/core/tests/suite/truncation.rs

@@ -523,6 +523,7 @@ async fn mcp_image_output_preserves_image_and_no_text_summary() -> Result<()> {
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(fixture.cwd.path().to_path_buf()),
                 approval_policy: Some(AskForApproval::Never),

codex-rs/core/tests/suite/unified_exec.rs

@@ -200,6 +200,7 @@ async fn submit_unified_exec_turn(
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(test.config.cwd.to_path_buf()),
                 approval_policy: Some(AskForApproval::Never),
@@ -291,6 +292,7 @@ async fn unified_exec_intercepts_apply_patch_exec_command() -> Result<()> {
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(cwd),
                 approval_policy: Some(AskForApproval::Never),
@@ -2146,6 +2148,7 @@ async fn unified_exec_keeps_long_running_session_after_turn_end() -> Result<()>
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(turn_cwd),
                 approval_policy: Some(AskForApproval::Never),
@@ -2249,6 +2252,7 @@ async fn unified_exec_interrupt_preserves_long_running_session() -> Result<()> {
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(turn_cwd),
                 approval_policy: Some(AskForApproval::Never),
@@ -2721,6 +2725,7 @@ async fn unified_exec_runs_under_sandbox() -> Result<()> {
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(turn_cwd),
                 approval_policy: Some(AskForApproval::Never),
@@ -2843,6 +2848,7 @@ async fn unified_exec_enforces_glob_deny_read_policy() -> Result<()> {
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(turn_cwd),
                 approval_policy: Some(AskForApproval::Never),
@@ -2981,6 +2987,7 @@ async fn unified_exec_python_prompt_under_seatbelt() -> Result<()> {
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(turn_cwd),
                 approval_policy: Some(AskForApproval::Never),

codex-rs/core/tests/suite/user_notification.rs

@@ -64,6 +64,7 @@ mv "${tmp_path}" "${payload_path}""#,
             }],
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: Default::default(),
         })
         .await?;

codex-rs/core/tests/suite/user_shell_cmd.rs

@@ -182,6 +182,7 @@ async fn user_shell_command_does_not_replace_active_turn() -> anyhow::Result<()>
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(cwd),
                 approval_policy: Some(AskForApproval::Never),

codex-rs/core/tests/suite/view_image.rs

@@ -77,6 +77,7 @@ fn disabled_user_turn(test: &TestCodex, items: Vec<UserInput>, model: String) ->
         environments: None,
         final_output_json_schema: None,
         responsesapi_client_metadata: None,
+        additional_context: Default::default(),
         thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
             cwd: Some(test.config.cwd.to_path_buf()),
             approval_policy: Some(AskForApproval::Never),

codex-rs/core/tests/suite/websocket_fallback.rs

@@ -160,6 +160,7 @@ async fn websocket_fallback_hides_first_websocket_retry_stream_error() -> Result
             environments: None,
             final_output_json_schema: None,
             responsesapi_client_metadata: None,
+            additional_context: Default::default(),
             thread_settings: codex_protocol::protocol::ThreadSettingsOverrides {
                 cwd: Some(cwd.path().to_path_buf()),
                 approval_policy: Some(AskForApproval::Never),