diff --git a/codex-rs/app-server-protocol/schema/json/ClientRequest.json b/codex-rs/app-server-protocol/schema/json/ClientRequest.json
index e57ffa12c..62495a79a 100644
--- a/codex-rs/app-server-protocol/schema/json/ClientRequest.json
+++ b/codex-rs/app-server-protocol/schema/json/ClientRequest.json
@@ -2864,6 +2864,12 @@
     },
     "WindowsSandboxSetupStartParams": {
       "properties": {
+        "cwd": {
+          "type": [
+            "string",
+            "null"
+          ]
+        },
         "mode": {
           "$ref": "#/definitions/WindowsSandboxSetupMode"
         }
@@ -3908,4 +3914,4 @@
     }
   ],
   "title": "ClientRequest"
-}
\ No newline at end of file
+}
diff --git a/codex-rs/app-server-protocol/schema/json/codex_app_server_protocol.schemas.json b/codex-rs/app-server-protocol/schema/json/codex_app_server_protocol.schemas.json
index 2ccd20466..f09f2fc55 100644
--- a/codex-rs/app-server-protocol/schema/json/codex_app_server_protocol.schemas.json
+++ b/codex-rs/app-server-protocol/schema/json/codex_app_server_protocol.schemas.json
@@ -15325,6 +15325,12 @@
       "WindowsSandboxSetupStartParams": {
         "$schema": "http://json-schema.org/draft-07/schema#",
         "properties": {
+          "cwd": {
+            "type": [
+              "string",
+              "null"
+            ]
+          },
           "mode": {
             "$ref": "#/definitions/v2/WindowsSandboxSetupMode"
           }
@@ -15385,4 +15391,4 @@
   },
   "title": "CodexAppServerProtocol",
   "type": "object"
-}
\ No newline at end of file
+}
diff --git a/codex-rs/app-server-protocol/schema/json/codex_app_server_protocol.v2.schemas.json b/codex-rs/app-server-protocol/schema/json/codex_app_server_protocol.v2.schemas.json
index 1bbea24c8..7f37aaecb 100644
--- a/codex-rs/app-server-protocol/schema/json/codex_app_server_protocol.v2.schemas.json
+++ b/codex-rs/app-server-protocol/schema/json/codex_app_server_protocol.v2.schemas.json
@@ -14226,6 +14226,12 @@
     "WindowsSandboxSetupStartParams": {
       "$schema": "http://json-schema.org/draft-07/schema#",
       "properties": {
+        "cwd": {
+          "type": [
+            "string",
+            "null"
+          ]
+        },
         "mode": {
           "$ref": "#/definitions/WindowsSandboxSetupMode"
         }
@@ -14285,4 +14291,4 @@
   },
   "title": "CodexAppServerProtocolV2",
   "type": "object"
-}
\ No newline at end of file
+}
diff --git a/codex-rs/app-server-protocol/schema/json/v2/WindowsSandboxSetupStartParams.json b/codex-rs/app-server-protocol/schema/json/v2/WindowsSandboxSetupStartParams.json
index 6f0663d20..663d36064 100644
--- a/codex-rs/app-server-protocol/schema/json/v2/WindowsSandboxSetupStartParams.json
+++ b/codex-rs/app-server-protocol/schema/json/v2/WindowsSandboxSetupStartParams.json
@@ -10,6 +10,12 @@
     }
   },
   "properties": {
+    "cwd": {
+      "type": [
+        "string",
+        "null"
+      ]
+    },
     "mode": {
       "$ref": "#/definitions/WindowsSandboxSetupMode"
     }
@@ -19,4 +25,4 @@
   ],
   "title": "WindowsSandboxSetupStartParams",
   "type": "object"
-}
\ No newline at end of file
+}
diff --git a/codex-rs/app-server-protocol/schema/typescript/v2/WindowsSandboxSetupStartParams.ts b/codex-rs/app-server-protocol/schema/typescript/v2/WindowsSandboxSetupStartParams.ts
index 21daf6462..cb342c24c 100644
--- a/codex-rs/app-server-protocol/schema/typescript/v2/WindowsSandboxSetupStartParams.ts
+++ b/codex-rs/app-server-protocol/schema/typescript/v2/WindowsSandboxSetupStartParams.ts
@@ -3,4 +3,4 @@
 // This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
 import type { WindowsSandboxSetupMode } from "./WindowsSandboxSetupMode";
 
-export type WindowsSandboxSetupStartParams = { mode: WindowsSandboxSetupMode, };
+export type WindowsSandboxSetupStartParams = { mode: WindowsSandboxSetupMode, cwd?: string | null, };
diff --git a/codex-rs/app-server-protocol/src/protocol/v2.rs b/codex-rs/app-server-protocol/src/protocol/v2.rs
index 2147295c9..185d74fad 100644
--- a/codex-rs/app-server-protocol/src/protocol/v2.rs
+++ b/codex-rs/app-server-protocol/src/protocol/v2.rs
@@ -3927,6 +3927,8 @@ pub enum WindowsSandboxSetupMode {
 #[ts(export_to = "v2/")]
 pub struct WindowsSandboxSetupStartParams {
     pub mode: WindowsSandboxSetupMode,
+    #[ts(optional = nullable)]
+    pub cwd: Option<PathBuf>,
 }
 
 #[derive(Serialize, Deserialize, Debug, Clone, PartialEq, JsonSchema, TS)]
diff --git a/codex-rs/app-server/README.md b/codex-rs/app-server/README.md
index 068d4ee18..fa1627219 100644
--- a/codex-rs/app-server/README.md
+++ b/codex-rs/app-server/README.md
@@ -157,7 +157,7 @@ Example with notification opt-out:
 - `tool/requestUserInput` — prompt the user with 1–3 short questions for a tool call and return their answers (experimental).
 - `config/mcpServer/reload` — reload MCP server config from disk and queue a refresh for loaded threads (applied on each thread's next active turn); returns `{}`. Use this after editing `config.toml` without restarting the server.
 - `mcpServerStatus/list` — enumerate configured MCP servers with their tools, resources, resource templates, and auth status; supports cursor+limit pagination.
-- `windowsSandbox/setupStart` — start Windows sandbox setup for the selected mode (`elevated` or `unelevated`); returns `{ started: true }` immediately and later emits `windowsSandbox/setupCompleted`.
+- `windowsSandbox/setupStart` — start Windows sandbox setup for the selected mode (`elevated` or `unelevated`); accepts an optional `cwd` to target setup for a specific workspace, returns `{ started: true }` immediately, and later emits `windowsSandbox/setupCompleted`.
 - `feedback/upload` — submit a feedback report (classification + optional reason/logs, conversation_id, and optional `extraLogFiles` attachments array); returns the tracking thread id.
 - `command/exec` — run a single command under the server sandbox without starting a thread/turn (handy for utilities and validation).
 - `config/read` — fetch the effective config on disk after resolving config layering.
diff --git a/codex-rs/app-server/src/codex_message_processor.rs b/codex-rs/app-server/src/codex_message_processor.rs
index 80558642c..8d9f08ce6 100644
--- a/codex-rs/app-server/src/codex_message_processor.rs
+++ b/codex-rs/app-server/src/codex_message_processor.rs
@@ -6119,21 +6119,39 @@ impl CodexMessageProcessor {
             WindowsSandboxSetupMode::Unelevated => CoreWindowsSandboxSetupMode::Unelevated,
         };
         let config = Arc::clone(&self.config);
+        let cli_overrides = self.cli_overrides.clone();
+        let cloud_requirements = self.current_cloud_requirements();
+        let command_cwd = params.cwd.unwrap_or_else(|| config.cwd.clone());
         let outgoing = Arc::clone(&self.outgoing);
         let connection_id = request_id.connection_id;
 
         tokio::spawn(async move {
-            let setup_request = WindowsSandboxSetupRequest {
-                mode,
-                policy: config.permissions.sandbox_policy.get().clone(),
-                policy_cwd: config.cwd.clone(),
-                command_cwd: config.cwd.clone(),
-                env_map: std::env::vars().collect(),
-                codex_home: config.codex_home.clone(),
-                active_profile: config.active_profile.clone(),
+            let derived_config = derive_config_for_cwd(
+                &cli_overrides,
+                None,
+                ConfigOverrides {
+                    cwd: Some(command_cwd.clone()),
+                    ..Default::default()
+                },
+                Some(command_cwd.clone()),
+                &cloud_requirements,
+            )
+            .await;
+            let setup_result = match derived_config {
+                Ok(config) => {
+                    let setup_request = WindowsSandboxSetupRequest {
+                        mode,
+                        policy: config.permissions.sandbox_policy.get().clone(),
+                        policy_cwd: config.cwd.clone(),
+                        command_cwd,
+                        env_map: std::env::vars().collect(),
+                        codex_home: config.codex_home.clone(),
+                        active_profile: config.active_profile.clone(),
+                    };
+                    codex_core::windows_sandbox::run_windows_sandbox_setup(setup_request).await
+                }
+                Err(err) => Err(err.into()),
             };
-            let setup_result =
-                codex_core::windows_sandbox::run_windows_sandbox_setup(setup_request).await;
             let notification = WindowsSandboxSetupCompletedNotification {
                 mode: match mode {
                     CoreWindowsSandboxSetupMode::Elevated => WindowsSandboxSetupMode::Elevated,
diff --git a/codex-rs/app-server/tests/suite/v2/windows_sandbox_setup.rs b/codex-rs/app-server/tests/suite/v2/windows_sandbox_setup.rs
index 1f069b3ca..4512d9058 100644
--- a/codex-rs/app-server/tests/suite/v2/windows_sandbox_setup.rs
+++ b/codex-rs/app-server/tests/suite/v2/windows_sandbox_setup.rs
@@ -37,6 +37,7 @@ async fn windows_sandbox_setup_start_emits_completion_notification() -> Result<(
     let request_id = mcp
         .send_windows_sandbox_setup_start_request(WindowsSandboxSetupStartParams {
             mode: WindowsSandboxSetupMode::Unelevated,
+            cwd: None,
         })
         .await?;
     let response: JSONRPCResponse = timeout(