70 Commits

  • [codex] Restore v1 delegation guidance (#30511)
    ## Summary
    
    - restore the v1 clarification that requests for depth, research, or
    investigation do not authorize subagent spawning
    - restore guidance for keeping critical-path, urgent, tightly coupled,
    or difficult work local
    - update the focused v1 tool-search and spawn-description coverage
    
    ## Why
    
    PR #27919 simplified the v1 `spawn_agent` prompt by removing its
    delegation decision guidance. That left the authorization rule intact,
    but removed the instructions that constrained what should be delegated
    after spawning was authorized.
    
    Restore those guardrails while preserving later support for explicit
    delegation authorization from applicable AGENTS.md and skill
    instructions. Multi-agent v2 prompts are unchanged.
    
    ## User impact
    
    Models using the v1 multi-agent tool surface receive clearer guidance to
    delegate independent side work while keeping blocking work on the main
    rollout.
    
    ## Validation
    
    - `just fmt`
    - `git diff --check`
    - tests not run locally per repository guidance; CI will validate the
    focused coverage
  • [codex] allow AGENTS.md and skills to authorize delegation (#30274)
    Prompt update of MAv2 to include agents.md and skills more explicitly
    
    should mimic: https://github.com/openai/codex/pull/27919
  • Expose MCP app identity in app context (#29934)
    ## Why
    
    MCP tool-call events need to expose trusted app identity and action
    metadata directly so v2 clients do not have to infer it from tool names
    or resource URIs.
    
    ## What changed
    
    - Add optional `appName`, `templateId`, and `actionName` fields to MCP
    tool-call `appContext`.
    - Populate `appName` and `templateId` from trusted Codex Apps metadata,
    and derive `actionName` from the trusted app resource metadata.
    - Preserve all three fields through core events, legacy protocol events,
    persisted thread history, resume redaction, and app-server v2 responses.
    - Document the public `appContext` fields in
    `codex-rs/app-server/README.md`.
    - Regenerate app-server JSON and TypeScript schemas and add coverage for
    serialization, persistence, redaction, and metadata propagation.
    
    ## Validation
    
    - `just test -p codex-app-server-protocol mcp_tool_call`
    - `just test -p codex-core
    mcp_tool_call_item_metadata_only_trusts_codex_apps_identity
    mcp_tool_call_item_includes_app_identity`
    - `just write-app-server-schema`
    
    ---------
    
    Co-authored-by: Martin Au-Yeung <280153141+martinauyeung-oai@users.noreply.github.com>
  • Represent MCP authentication with an enum (#29924)
    ## Why
    
    MCP authentication has distinct OAuth and ChatGPT-session flows.
    Representing that choice as `use_chatgpt_auth` makes one flow implicit
    and allows the configuration model to express the distinction only
    through a boolean.
    
    ChatGPT credential forwarding also needs a first-party trust boundary. A
    configurable `chatgpt_base_url` controls routing, but must not grant an
    MCP server permission to receive session credentials.
    
    This change builds on #29733, where the boolean was introduced.
    
    ## What changed
    
    - Replace `use_chatgpt_auth` with an `auth` field backed by the
    exhaustive `McpServerAuth` enum.
    - Support `auth = "oauth"` and `auth = "chatgpt"`, with OAuth remaining
    the default.
    - Trust only the origin derived from the existing hardcoded
    `CHATGPT_CODEX_BASE_URL` when granting ChatGPT auth to an MCP server.
    - Keep configured bearer tokens and authorization headers ahead of the
    selected authentication flow.
    - Update config writers, schema output, fixtures, and integration-test
    setup to use the enum.
    
    ## Verification
    
    Integration coverage exercises the complete streamable HTTP startup path
    in two independent configurations:
    
    - A directly constructed MCP configuration verifies that matching an
    overridden `chatgpt_base_url` does not grant ChatGPT auth.
    - A persisted `config.toml` containing an attacker-controlled
    `chatgpt_base_url` and `auth = "chatgpt"` verifies the same boundary
    through normal config parsing.
    
    Both tests complete MCP initialization and tool listing and assert that
    the full captured request sequence contains no authorization headers.
    Separate integration coverage verifies that configured authorization
    takes precedence over ChatGPT auth.
  • Allow ChatGPT-hosted MCP servers to use session auth (#29733)
    ## Why
    
    ChatGPT session authentication was inferred from the reserved Codex Apps
    server name. That couples credential routing to Codex Apps-specific
    behavior and prevents other MCP endpoints hosted by ChatGPT from
    explicitly using the current session.
    
    The opt-in also needs a clear security boundary: an arbitrary MCP
    configuration must not be able to redirect ChatGPT credentials to
    another origin.
    
    ## What changed
    
    - Add `use_chatgpt_auth` to HTTP MCP server configuration, defaulting to
    `false`.
    - Honor the setting only when the parsed server URL has the same HTTP(S)
    origin as the configured `chatgpt_base_url`; otherwise remove the
    capability before startup.
    - Resolve bearer tokens and static or environment-backed authorization
    headers before selecting authentication, with configured authorization
    taking precedence over ChatGPT session auth.
    - Enable the setting for the built-in Codex Apps and hosted plugin
    runtime endpoints while keeping Codex Apps caching and tool
    normalization scoped to the reserved server.
    - Persist the setting through MCP config rewrite paths and expose it in
    the generated config schema.
    - Load the current login state for `codex mcp list` so reported auth
    status matches runtime behavior.
    
    ## Verification
    
    Core integration coverage exercises the complete streamable HTTP MCP
    startup path and verifies that:
    
    - a same-origin opted-in server receives the current ChatGPT access
    token;
    - an explicitly configured authorization header takes precedence;
    - a different-origin server completes MCP initialization and tool
    listing without receiving any ChatGPT authorization header.
  • [codex] Use tool search for MCP tools by default (#29486)
    ## Why
    
    MCP tools were only placed behind `tool_search` when a feature flag was
    enabled or when there were at least 100 tools. That made the model's
    tool flow depend on both rollout configuration and the number of
    installed tools.
    
    The searched-tool flow is now the intended behavior. Making it
    unconditional when the model and provider support it gives every
    supported setup the same behavior and lets us retire the feature flag
    safely.
    
    ## What changed
    
    - Defer all effective MCP tools when `tool_search` and namespaced tools
    are supported.
    - Keep exposing MCP tools directly when search cannot be used, so older
    or unsupported model/provider combinations still work.
    - Mark `tool_search_always_defer_mcp_tools` as removed and ignore old
    configured values.
    - Keep plugin filtering, app-only filtering, file handling, and MCP
    calls working through the searched-tool flow.
    
    ## Why many tests changed
    
    Many tests used to act as if the model could see MCP tools in its first
    request and call them immediately. That is no longer the real flow: the
    model first receives `tool_search`, searches for a tool, receives the
    matching MCP tool, and then calls it in the next request.
    
    The tests therefore needed an extra search step, and checks for tool
    names, descriptions, and input fields had to move from the first request
    to the search result. These are not separate product changes; they make
    the tests follow what the model will actually see after this change. The
    plugin tests still check which tools are allowed and where they came
    from, the file tests still check upload fields and behavior, and the MCP
    round-trip test still checks a successful call from start to finish.
    
    ## Tests
    
    - `just test -p codex-features`
    - Focused `codex-core` tests for MCP exposure and tool planning
    - `just test -p codex-core explicit_plugin_mentions`
    - `just test -p codex-core stdio_server_round_trip`
    - Focused `codex-core` tests for tool search, app-only tools, and MCP
    file uploads
  • Emit Trusted MCP App Identity on Tool-Call Items (#27132)
    ## Summary
    
    - Add optional `appContext` to app-server MCP tool-call items with
    trusted `connectorId`, `linkId`, and `mcpAppResourceUri` metadata.
    - Preserve that context across tool-call events, persisted history,
    reconnects, and thread resume.
    - Keep the deprecated top-level `mcpAppResourceUri` temporarily for
    client migration.
    
    The consumer contract is `{ appContext: { connectorId, linkId,
    mcpAppResourceUri }, tool }`.
    
    ## Validation
    
    - Full GitHub Actions suite passes, including CLA, Bazel tests, clippy,
    release builds, and argument-comment lint.
    
    ---------
    
    Co-authored-by: martinauyeung-oai <280153141+martinauyeung-oai@users.noreply.github.com>
  • [codex] Use expect in integration tests (#28441)
    The workspace denies `clippy::expect_used` in production. Although
    `clippy.toml` allows `expect` in tests, Bazel Clippy compiles
    integration-test helper code in a way that does not receive that
    exemption, which encouraged verbose `unwrap_or_else(... panic!(...))`
    and equivalent `match`/`let else` forms.
    
    This allows `clippy::expect_used` once at each integration-test crate
    root (including aggregated suites and test-support libraries), then
    replaces manual panic-based Result and Option unwraps with
    `expect`/`expect_err`. Standalone `tests/*.rs` files remain their own
    crate roots. Intentional assertion and unexpected-variant panics remain
    unchanged, and the production `expect_used = "deny"` lint remains in
    place.
    
    The cleanup is mechanical and net-negative in line count.
  • Represent dynamic tools with explicit namespaces internally (#27365)
    Follow-up to #27356.
    
    ## Stack note
    
    This PR changes Codex's internal dynamic-tool shape while leaving
    `thread/start` unchanged. App-server therefore converts the existing
    per-tool input into explicit functions and namespaces before passing it
    to core.
    
    [#27371](https://github.com/openai/codex/pull/27371) updates
    `thread/start` to use the same explicit shape and removes this temporary
    conversion.
    
    ## Why
    
    Dynamic tools repeat namespace metadata on every function. Core should
    keep one explicit namespace with its member tools so descriptions and
    membership stay consistent across sessions and runtime planning.
    
    ## What changed
    
    - Represent dynamic tools as top-level functions or explicit namespaces
    in protocol and session state.
    - Read old flat rollout metadata and write the canonical hierarchy.
    - Flatten namespace members only when registering callable tools.
    - Keep `thread/start.dynamicTools` flat for now and normalize it at the
    app-server boundary.
    
    New builds can read old rollout metadata. Older builds cannot read newly
    written hierarchical metadata.
    
    ## Test plan
    
    - `just test -p codex-app-server
    thread_start_normalizes_legacy_dynamic_tools_into_model_request`
    - `just test -p codex-protocol
    session_meta_normalizes_legacy_dynamic_tools`
    - `just test -p codex-core
    resume_restores_dynamic_tools_from_rollout_with_sqlite_enabled`
    - `just test -p codex-core
    tool_search_returns_deferred_dynamic_tool_and_routes_follow_up_call`
    - `just test -p codex-core code_mode_can_call_hidden_dynamic_tools`
    - `just test -p codex-tools`
  • chore: prompt MAv2 (#27919)
    Prompt update of MAv2
  • Pair thread environment settings (#26687)
    ## Why
    
    Thread cwd and environment selections are a single logical setting in
    core: updating one without the other can silently desynchronize the
    next-turn execution context. This change makes that relationship
    explicit in the internal thread settings flow while preserving the
    existing app-server public API shape.
    
    ## What changed
    
    - Moved the cwd/environment pair through internal
    `ThreadSettingsOverrides.environment_settings` instead of a top-level
    internal `cwd` field.
    - Kept `thread/settings/update` public params unchanged, with app-server
    translating top-level `cwd` into the paired internal settings shape.
    - Moved `Op::UserInput` environment overrides into thread settings so
    user turns and settings updates use the same core path.
    - Updated core, app-server, MCP, memories, sample, and test callsites to
    construct the paired settings shape.
    
    ## Verification
    
    - `git diff --check`
    - Local test run starting after PR creation.
  • app-server: remove experimental persist_extended_history bool flag (#25712)
    ## Summary
    
    Remove the dead experimental `persistExtendedHistory` app-server flag
    and collapse rollout persistence to the single policy app-server already
    used.
    
    ## What Changed
    
    - Removed `persistExtendedHistory` from v2 thread start/resume/fork
    params and deleted its deprecation notice path.
    - Removed the persistence-mode enums and plumbing through core, rollout,
    and thread-store.
    - Made rollout filtering mode-free, keeping the existing limited
    persisted-history behavior.
    
    ## Test Plan
    
    - `just write-app-server-schema`
    - `cargo nextest run --no-fail-fast -p codex-app-server-protocol
    schema_fixtures`
    - `cargo nextest run --no-fail-fast -p codex-app-server
    thread_shell_command_history_responses_exclude_persisted_command_executions`
    - `cargo nextest run --no-fail-fast -p codex-rollout -p
    codex-thread-store`
    - final `rg` for removed flag/type names
  • [codex] Wait for MCP readiness in core integration tests (#24964)
    Ensures MCP-backed `codex-core` integration tests exercise initialized
    servers instead of racing server startup.
    
    I've been idly investigating a few flakes and the failure modes are much
    more confusing when a tool call fails because of a failed server start
    than when the failed server start causes the test to fail directly.
  • [codex] Improve built-in tool schema docs (#24794)
    ## Summary
    - Clarify default, omission, and bounded behavior across built-in tool
    schemas, including unified exec, classic shell, Code Mode exec/wait,
    multi-agent, agent job, MCP resource, image, goal, plan, tool_search,
    and test-sync fields.
    - Convert update_plan status to an enum and add short field descriptions
    where the schema previously relied on surrounding context.
    - Remove the dedicated permission-approval schema test and keep only
    updates to existing expected-spec tests.
    
    ## Validation
    - Ran `just fmt`.
    - Ran `git diff --check`.
    - Did not run clippy or tests, per request.
    
    Regression has been eval
    [here](https://openai.slack.com/archives/C09GDSP1J9X/p1779905065496949)
    and we proved there are no regressions
  • 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.
  • Move MCP tool naming mode into manager (#21576)
    ## Why
    
    The `non_prefixed_mcp_tool_names` feature should be applied where MCP
    tools become model-visible, not by remapping names later in core.
    Keeping the decision in `McpConnectionManager` construction makes
    `ToolInfo` the single shaped view that spec building, deferred tool
    search, routing, and unavailable-tool placeholders can consume directly.
    
    This also preserves the existing external behavior while the feature is
    off, and keeps the feature-on behavior for code mode and hooks explicit
    at the manager boundary.
    
    ## What Changed
    
    - Add `McpToolNameMode` to `codex-mcp` and flow it through `McpConfig`
    into `McpConnectionManager::new`.
    - Normalize MCP `ToolInfo` names in the manager using either
    legacy-prefixed namespaces or non-prefixed namespaces; the legacy path
    adds `mcp__` without restoring the old trailing namespace suffix.
    - Remove the core-side MCP name remapping path so specs, tool search,
    session resolution, and unavailable-tool placeholder construction use
    the manager-provided `ToolName` values directly.
    - Keep code mode flattening on the `__` namespace separator.
    - Preserve hook compatibility by giving non-prefixed MCP hook names
    legacy `mcp__...` matcher aliases.
    - Add/adjust integration and unit coverage for non-prefixed code-mode
    behavior, hook matching with the feature on and off, and manager-level
    legacy prefixing.
    
    ## Testing
    
    - `cargo test -p codex-mcp --lib`
    - `cargo test -p codex-core --lib tools::spec::tests -- --nocapture`
    - `cargo test -p codex-core --lib mcp_tools -- --nocapture`
    - `cargo test -p codex-core --lib mcp_tool_exposure -- --nocapture`
    - `cargo test -p codex-core --test all mcp_tool -- --nocapture`
    - `cargo test -p codex-core --test all search_tool -- --nocapture`
    - `cargo test -p codex-core --test all hooks_mcp -- --nocapture`
    - `cargo test -p codex-core --test all
    code_mode_uses_non_prefixed_mcp_tool_names_when_feature_enabled --
    --nocapture`
    - `cargo test -p codex-tools`
    - `cargo test -p codex-features`
  • Route MCP servers through explicit environments (#23583)
    ## Summary
    - route each configured MCP server through an explicit per-server
    `environment_id` instead of a manager-wide remote toggle
    - default omitted `environment_id` to `local`, resolve named ids through
    `EnvironmentManager`, and fail only the affected MCP server when an
    explicit id is unknown
    - keep local stdio on the existing local launcher path for now, while
    named-environment stdio uses the selected environment backend and
    requires an absolute `cwd`
    - allow local HTTP MCP servers to keep using the ambient HTTP client
    when no local `Environment` is configured; named-environment HTTP MCPs
    use that environment's HTTP client
    
    ## Validation
    - devbox Bazel build: `bazel build --bes_backend= --bes_results_url=
    //codex-rs/cli:codex //codex-rs/rmcp-client:test_stdio_server
    //codex-rs/rmcp-client:test_streamable_http_server`
    - devbox app-server config matrix with real `config.toml` /
    `environments.toml` files covering omitted local, explicit local,
    omitted local under remote default, explicit remote stdio, local HTTP
    without local env, explicit remote HTTP, local stdio without local env,
    unknown explicit env, and remote stdio without `cwd`
  • chore: namespace v1 sub-agent tools (#23475)
    ## Why
    
    The v1 sub-agent tools are a single tool family, but they were exposed
    as separate flat function tools. This makes the model-visible surface
    less clearly grouped and leaves the legacy names in the same flat
    namespace as newer agent tooling.
    
    ## What
    
    - Wraps the v1 `spawn_agent`, `send_input`, `resume_agent`,
    `wait_agent`, and `close_agent` specs in the `multi_agent_v1` namespace.
    - Registers the corresponding handlers with namespaced runtime tool
    names.
    - Updates tool-planning, deferred tool search, and sub-agent
    notification tests to assert the namespace shape and child `spawn_agent`
    lookup.
    
    ## Verification
    
    - Updated `codex-core` coverage for the v1 multi-agent tool plan,
    deferred tool search output, and sub-agent tool descriptions.
  • Defer v1 multi-agent tools behind tool search (#23144)
    Summary: defer v1 multi-agent tools when tool_search and namespace tools
    are available; keep concise searchable descriptions and move the v1
    usage guidance into developer instructions; add targeted coverage.
    Testing: not run per request; ran just fmt.
  • Remove explicit connector tool undeferral (#23390)
    ## Summary
    - remove the explicit-connector carveout that kept mentioned app tools
    directly exposed instead of deferred
    - keep the surviving explicit-mention reconstruction only for analytics,
    preserving `codex_app_mentioned` and `codex_app_used.invoke_type`
    - trim the now-unused prompt/tool-exposure plumbing and refresh coverage
    around always-defer behavior
    
    ## Verification
    - `just fmt`
    - `cargo test -p codex-analytics`
    - `cargo test -p codex-core` *(one transient timeout in
    `shell_snapshot::tests::macos_zsh_snapshot_includes_sections`; isolated
    rerun passed)*
    - `cargo test -p codex-core --lib
    shell_snapshot::tests::macos_zsh_snapshot_includes_sections`
    - `cargo test -p codex-core --test all
    explicit_app_mentions_respect_always_defer`
    - `cargo test -p codex-core --lib
    mcp_tool_exposure::tests::always_defer_feature_defers_apps_too`
    - `just fix -p codex-analytics`
    - `just fix -p codex-core`
  • [1 of 7] Add thread settings to UserInput (#23080)
    **Stack position:** [1 of 7]
    
    ## Summary
    
    The first three PRs in this stack are a cleanup pass before the actual
    thread settings API work.
    
    Today, core has several overlapping "user input" ops: `UserInput`,
    `UserInputWithTurnContext`, and `UserTurn`. They differ mostly in how
    much next-turn state they carry, which makes the later queued thread
    settings update harder to reason about and review.
    
    This PR starts that cleanup by adding the shared
    `ThreadSettingsOverrides` payload and allowing `Op::UserInput` to carry
    it. Existing variants remain in place here, so this layer is mostly a
    behavior-preserving API shape change plus mechanical constructor
    updates.
    
    ## End State After PR3
    
    By the end of PR3, `Op::UserInput` is the only "user input" core op. It
    can carry optional thread settings overrides for callers that need to
    update stored defaults with a turn, while callers without updates use
    empty settings. `Op::UserInputWithTurnContext` and `Op::UserTurn` are
    deleted.
    
    ## End State After PR5
    
    By the end of PR5, core will have only two ops for this area:
    
    - `Op::UserInput` for user-input-bearing submissions.
    - `Op::ThreadSettings` for settings-only updates.
    
    ## Stack
    
    1. [1 of 7] [Add thread settings to
    UserInput](https://github.com/openai/codex/pull/23080) (this PR)
    2. [2 of 7] [Remove
    UserInputWithTurnContext](https://github.com/openai/codex/pull/23081)
    3. [3 of 7] [Remove
    UserTurn](https://github.com/openai/codex/pull/23075)
    4. [4 of 7] [Placeholder for OverrideTurnContext
    cleanup](https://github.com/openai/codex/pull/23087)
    5. [5 of 7] [Replace OverrideTurnContext with
    ThreadSettings](https://github.com/openai/codex/pull/22508)
    6. [6 of 7] [Add app-server thread settings
    API](https://github.com/openai/codex/pull/22509)
    7. [7 of 7] [Sync TUI thread
    settings](https://github.com/openai/codex/pull/22510)
  • Remove ToolSearch feature toggle (#23389)
    ## Summary
    - mark `ToolSearch` as removed and ignore stale config writes for its
    legacy key
    - make search tool exposure depend only on model capability, not a
    feature toggle
    - remove app-server enablement support and prune now-obsolete test
    coverage/setup
    
    ## Verification
    - `cargo test -p codex-features`
    - `cargo test -p codex-tools`
    - `cargo test -p codex-core search_tool_requires_model_capability`
    - `cargo test -p codex-app-server experimental_feature_enablement_set_`
    
    ## Notes
    - This keeps the legacy config key as a no-op for compatibility while
    removing the ability to toggle the behavior off cleanly.
    - No developer-facing docs update outside the touched app-server README
    was needed.
  • Add user_input_requested_during_turn to MCP turn metadata (#22237)
    ## Why
    - Similar change as https://github.com/openai/codex/pull/21219
    - Without change: MCP tool calls receive
    `_meta["x-codex-turn-metadata"]` with various key values.
    - Issue: MCP servers currently do not know if user input was requested
    during the turn (Ex: Model decides to prompt the user for approval
    mid-turn before making a possibly risky tool call). MCP servers may want
    to know this when tracking latency metrics because these instances are
    inflated.
    
    ## What Changed
    - With change: MCP turn metadata now includes
    `user_input_requested_during_turn` when a model-visible
    `request_user_input` call happened earlier in the turn, propagated in
    `_meta["x-codex-turn-metadata"]`.
    - `mark_turn_user_input_requested()` is called when user input is
    requested through either MCP elicitation (`mcp.rs`) or the
    `request_user_input` tool (`mod.rs`).
    - MCP tool call `_meta` is now built immediately before execution
    (`mcp_tool_call.rs`) so user input requested earlier in the same turn,
    including within the same tool call via elicitation, is reflected in the
    metadata.
    - Normal `/responses` turn metadata headers are unchanged.
    
    ## Verification
    - `codex-rs/core/src/session/mcp_tests.rs`
    - `codex-rs/core/src/tools/handlers/request_user_input_tests.rs`
    - `codex-rs/core/src/turn_metadata_tests.rs`
    - `codex-rs/core/tests/suite/search_tool.rs`
  • Support explicit MCP OAuth client IDs (#22575)
    ## Why
    Some MCP OAuth providers require a pre-registered public client ID and
    cannot rely on dynamic client registration. Codex already supports MCP
    OAuth, but it had no way to supply that client ID from config into the
    PKCE flow.
    
    ## What changed
    - add `oauth.client_id` under `[mcp_servers.<server>]` config, including
    config editing and schema generation
    - thread the configured client ID through CLI, app-server, plugin login,
    and MCP skill dependency OAuth entrypoints
    - configure RMCP authorization with the explicit client when present,
    while preserving the existing dynamic-registration path when it is
    absent
    - add focused coverage for config parsing/serialization and OAuth URL
    generation
    
    ## Verification
    - `cargo test -p codex-config -p codex-rmcp-client -p codex-mcp -p
    codex-core-plugins`
    - `cargo test -p codex-core blocking_replace_mcp_servers_round_trips
    --lib`
    - `cargo test -p codex-core
    replace_mcp_servers_streamable_http_serializes_oauth_resource --lib`
    - `cargo test -p codex-core config_schema_matches_fixture --lib`
    
    ## Notes
    Broader local package runs still hit unrelated pre-existing stack
    overflows in:
    - `codex-app-server::in_process_start_clamps_zero_channel_capacity`
    -
    `codex-core::resume_agent_from_rollout_uses_edge_data_when_descendant_metadata_source_is_stale`
  • Remove unavailable MCP placeholder tool backfill (#22439)
    ## Why
    
    `UnavailableDummyTools` kept synthetic placeholder tools alive for
    historical tool calls whose backing MCP tool was no longer available.
    That path adds stale model-visible tool specs and special routing at the
    point where unavailable MCP calls should use ordinary current-tool
    handling. This removes the runtime backfill instead of preserving a
    second compatibility lane.
    
    ## Is it safe to remove?
    
    The unavailable tools were added in #17853 after a CS issue when a
    previously-called MCP tool failed to load and was omitted from the CS
    spec. Now that we have tool search, I think this is resolved:
    - API merges tools from previous TST output into effective tool set so
    theyre always in CS spec
    - if an MCP tool surfaced by TST later becomes unavailable, the model
    can still call it and it will just return model-visible error
    - both TST output and function call output are dropped on compaction so
    model will not remember old calls to MCP post compaction
    
    ## What changed
    
    - Delete unavailable-tool collection, placeholder handler, router/spec
    plumbing, and obsolete placeholder coverage.
    - Keep `features.unavailable_dummy_tools` as a removed no-op feature
    tombstone so existing configs still parse cleanly.
    - Add an integration-style `tool_search` regression test showing that a
    deferred MCP tool surfaced through `tool_search` still routes through
    MCP and returns a model-visible tool-call error rather than `unsupported
    call`.
    
    ## Verification
    
    - `cargo test -p codex-core tool_search`
  • [codex] Add search term coverage for tool_search (#22398)
    ## Why
    
    `tool_search` already had solid end-to-end coverage for discovery and
    follow-up execution, but it did not prove that distinct pieces of
    indexed search text actually work in integration. In particular, we were
    not exercising whether unique tool names, descriptions, namespaces,
    underscore-expanded dynamic names, and schema-property terms were
    sufficient to surface the expected deferred tools.
    
    This change adds focused integration coverage for those term sources so
    regressions in search text construction are caught by a real `TestCodex`
    flow instead of only by lower-level unit tests.
    
    ## What changed
    
    - added a small helper in `core/tests/suite/search_tool.rs` to assert
    that a `tool_search_output` contains an expected namespace child tool
    - added an MCP integration test that issues several `tool_search_call`s
    and verifies distinct query terms match the expected app tools:
      - exact tool name: `calendar_timezone_option_99`
      - tool description phrase: `uploaded document`
      - top-level schema property: `starts_at`
    - added a dynamic-tool integration test that verifies distinct query
    terms match the expected deferred dynamic tool:
      - exact name: `quasar_ping_beacon`
      - underscore-expanded name: `quasar ping beacon`
      - description phrase: `saffron metronome`
      - namespace: `orbit_ops`
      - schema property: `chrono_spec`
    
    ## Validation
    
    - `cargo test -p codex-core tool_search_matches_`
    
    ## Docs
    
    No documentation update needed.
  • feat: include thread ID in MCP turn metadata (#21329)
    ## Why
    
    MCP tool calls already include `session_id` in `x-codex-turn-metadata`,
    but descendant threads intentionally share that value with the root
    thread. Consumers that need to correlate work at the concrete thread
    level also need the current `thread_id`.
    
    ## What changed
    
    - add `thread_id` to `x-codex-turn-metadata` while preserving
    `session_id` as the shared session identity
    - thread the two identities separately through normal turns and spawned
    review threads
    - add regression coverage for resumed sessions, reserved metadata
    fields, and deferred MCP tool calls
    
    ## Verification
    
    - added focused coverage in `core/src/session/tests.rs`,
    `core/src/turn_metadata_tests.rs`, and `core/tests/suite/search_tool.rs`
  • feat: add session_id (#20437)
    ## Summary
    
    Related to
    https://openai.slack.com/archives/C095U48JNL9/p1777537279707449
    TLDR:
    We update the meaning of session ids and thread ids:
    * thread_id stays as now
    * session_id become a shared id between every thread under a /root
    thread (i.e. every sub-agent share the same session id)
    
    This PR introduces an explicit `SessionId` and threads it through the
    protocol/client boundary so `session_id` and `thread_id` can diverge
    when they need to, while preserving compatibility for older serialized
    `session_configured` events.
    
    ---------
    
    Co-authored-by: Codex <noreply@openai.com>
  • Add model and reasoning effort to MCP turn metadata (#21219)
    ## Why
    - Similar change as https://github.com/openai/codex/pull/19473.
    - Without change: MCP tool calls receive
    `_meta["x-codex-turn-metadata"]` with `session_id`, `turn_id`, and
    `turn_started_at_unix_ms`.
    - Issue: MCP servers may want the model and reasoning effort to better
    understand tool-call behavior and latency relative to turn start.
    
    ## What Changed
    - With change: MCP turn metadata now includes `model` and
    `reasoning_effort`, propagated in `_meta["x-codex-turn-metadata"]`.
    - Normal `/responses` turn metadata headers are unchanged.
    
    ## Verification
    - `codex-rs/core/src/mcp_tool_call_tests.rs`
    - `codex-rs/core/src/turn_metadata_tests.rs`
    - `codex-rs/core/tests/suite/search_tool.rs`
  • Use MCP server instructions in deferred namespace descriptions (#21053)
    ## Why
    
    MCP servers can provide `instructions` that explain what their tools are
    for. Directly exposed MCP namespaces already use those instructions when
    a connector description is not available, but deferred `tool_search`
    results did not preserve that fallback. The direct path falls back from
    connector metadata to server instructions, while the deferred path only
    carried `connector_description` and otherwise fell back to generic
    namespace text.
    
    That meant a plain MCP server could provide useful model-facing guidance
    and still appear as `Tools in the X namespace.` whenever it was
    discovered lazily through `tool_search`.
    
    ## What changed
    
    - Store one model-facing `namespace_description` on `ToolInfo`, using
    connector descriptions for connector-backed tools and server
    instructions for plain MCP servers.
    - Thread that namespace description through the `tool_search` source
    list, search indexing, and returned namespace metadata.
    - Add an end-to-end regression test for deferred non-app MCP search
    results exposing server instructions as the namespace description.
    
    ## Verification
    
    - `cargo test -p codex-tools
    search_tool_description_lists_each_mcp_source_once --lib`
    - `cargo test -p codex-core --test all
    tool_search_uses_non_app_mcp_server_instructions_as_namespace_description`
  • Make thread store process-scoped (#19474)
    - Build one app-server process ThreadStore from startup config and share
    it with ThreadManager and CodexMessageProcessor.
    - Remove per-thread/fork store reconstruction so effective thread config
    cannot switch the persistence backend.
    - Add params to ThreadStore create/resume for specifying thread
    metadata, since otherwise the metadata from store creation would be used
    (incorrectly).
  • Add ThreadManager sample crate (#20141)
    Summary:
    - Add codex-thread-manager-sample, a one-shot binary that starts a
    ThreadManager thread, submits a prompt, and prints the final assistant
    output.
    - Pass ThreadStore into ThreadManager::new and expose
    thread_store_from_config for existing callsites.
    - Build the sample Config directly with only --model and prompt inputs.
    
    Verification:
    - just fmt
    - cargo check -p codex-thread-manager-sample -p codex-app-server -p
    codex-mcp-server
    - git diff --check
    
    Tests: Not run per request.
  • core tests: submit turns with permission profiles (#20010)
    ## Summary
    
    - Add `PermissionProfile`-based turn submission helpers to
    `core_test_support`, while keeping the legacy `SandboxPolicy` helper for
    tests that intentionally exercise legacy fallback behavior.
    - Switch the default `TestCodex::submit_turn()` path to send a real
    `PermissionProfile` plus the required legacy compatibility projection in
    `Op::UserTurn`.
    - Migrate straightforward app/search/shell/truncation tests from
    `SandboxPolicy::{DangerFullAccess, ReadOnly}` to
    `PermissionProfile::{Disabled, read_only}`.
    - Add a TUI compatibility projection helper for legacy app-server fields
    so non-legacy writable roots are preserved instead of being downgraded
    to read-only.
    - Fix remote start/resume/fork sandbox-mode projection to classify any
    managed profile with writable roots as workspace-write, not only
    profiles that can write `cwd`.
    - Reduce `SandboxPolicy` references in `codex-rs/core/tests` from 47
    files to 41 files without changing production behavior.
    
    ## Testing
    
    - `cargo check -p codex-core --tests`
    - `cargo test -p codex-tui
    compatibility_profile_preserves_unbridgeable_write_roots`
    - `cargo test -p codex-tui
    sandbox_mode_preserves_non_cwd_write_roots_for_remote_sessions`
    - `just fmt`
    - `just fix -p core_test_support`
    - `just fix -p codex-core`
  • Add turn start timestamp to turn metadata (#19473)
    ## Why
    - Without change: MCP tool calls receive
    `_meta["x-codex-turn-metadata"]` with `session_id` and `turn_id`.
    - Issue: MCP servers may want the turn start timestamp to measure
    internal latency relative to turn start.
    
    ## What Changed
    - With change: turn metadata now includes `turn_started_at_unix_ms`,
    which is propagated to MCP tool calls in
    `_meta["x-codex-turn-metadata"]`.
    
    ## Verification
    - `codex-rs/core/src/mcp_tool_call_tests.rs`
    - `codex-rs/core/src/turn_metadata_tests.rs`
    - `codex-rs/core/src/turn_timing_tests.rs`
    - `codex-rs/core/tests/responses_headers.rs`
    - `codex-rs/core/tests/suite/search_tool.rs`
  • fix: filter dynamic deferred tools from model_visible_specs (#19771)
    fixes #19486
    
    ### Problem
    Right now dynamic deferred tools are filtered at normal-turn prompt
    building time, rather than upstream while building the `ToolRouter`
    itself. This causes issues because dynamic deferred tools are then
    wrongly included in the router's `model_visible_specs`, which is what
    the compaction request-building flow relies on.
    
    ### Fix
    Move the dynamic deferred tool filtering to `ToolRouter` creation time
    to solve this problem for every request that relies on `ToolRouter` for
    `model_visible_specs`, which solves the issue generically.
    
    ### Tests
    Added unit + integration tests to ensure dynamic deferred tools are
    omitted from `model_visible_specs` and compaction request respectively.
    
    Tested against live `/compact` endpoint; raw deferred dynamic tools
    without `tool_search` returned `400` (current bug), while the filtered
    payload (this fix) returns `200`.
  • [codex] Forward Codex Apps tool call IDs to backend metadata (#19207)
    ## Summary
    - include the outer tool `call_id` in Codex Apps MCP request metadata
    under `_meta._codex_apps.call_id`
    - preserve existing Codex Apps metadata like `resource_uri` and
    `contains_mcp_source`
    - add request metadata coverage for both the existing-metadata and
    no-existing-metadata cases
    
    ## Why
    The paired backend change in
    [openai/openai#850796](https://github.com/openai/openai/pull/850796)
    updates MCP compliance logging to prefer `_meta._codex_apps.call_id`
    instead of the JSON-RPC request id. This client change sends that outer
    tool call id so the backend can record the model/tool call identifier
    when it is available.
    
    This is wire-compatible with older backends because `_meta._codex_apps`
    is already reserved backend-only metadata. Backends that do not read
    `call_id` will ignore the extra field.
    
    ## Testing
    - `cargo test -p codex-core request_meta`
    - `just fmt`
    - `just fix -p codex-core`
  • Add turn-scoped environment selections (#18416)
    ## Summary
    - add experimental turn/start.environments params for per-turn
    environment id + cwd selections
    - pass selections through core protocol ops and resolve them with
    EnvironmentManager before TurnContext creation
    - treat omitted selections as default behavior, empty selections as no
    environment, and non-empty selections as first environment/cwd as the
    turn primary
    
    ## Testing
    - ran `just fmt`
    - ran `just write-app-server-schema`
    - not run: unit tests for this stacked PR
    
    ---------
    
    Co-authored-by: Codex <noreply@openai.com>
  • [tool search] support namespaced deferred dynamic tools (#18413)
    Deferred dynamic tools need to round-trip a namespace so a tool returned
    by `tool_search` can be called through the same registry key that core
    uses for dispatch.
    
    This change adds namespace support for dynamic tool specs/calls,
    persists it through app-server thread state, and routes dynamic tool
    calls by full `ToolName` while still sending the app the leaf tool name.
    Deferred dynamic tools must provide a namespace; non-deferred dynamic
    tools may remain top-level.
    
    It also introduces `LoadableToolSpec` as the shared
    function-or-namespace Responses shape used by both `tool_search` output
    and dynamic tool registration, so dynamic tools use the same wrapping
    logic in both paths.
    
    Validation:
    - `cargo test -p codex-tools`
    - `cargo test -p codex-core tool_search`
    
    ---------
    
    Co-authored-by: Sayan Sisodiya <sayan@openai.com>
  • Update models.json (#18586)
    - Replace the active models-manager catalog with the deleted core
    catalog contents.
    - Replace stale hardcoded test model slugs with current bundled model
    slugs.
    - Keep this as a stacked change on top of the cleanup PR.
  • enable tool search over dynamic tools (#18263)
    ## Summary
    
    - Normalize deferred MCP and dynamic tools into `ToolSearchEntry` values
    before constructing `ToolSearchHandler`.
    - Move the tool-search entry adapter out of `tools/handlers` and into
    `tools/tool_search_entry.rs` so the handlers directory stays focused on
    handlers.
    - Keep `ToolSearchHandler` operating over one generic entry list for
    BM25 search, namespace grouping, and per-bucket default limits.
    
    ## Why
    
    Follow-up cleanup for #17849. The dynamic tool-search support made the
    handler juggle source-specific MCP and dynamic tool lists, index
    arithmetic, output conversion, and namespace emission. This keeps source
    adaptation outside the handler so the search loop itself is smaller and
    source-agnostic.
    
    ## Validation
    
    - `just fmt`
    - `cargo test -p codex-core tools::handlers::tool_search::tests`
    - `git diff --check`
    - `cargo test -p codex-core` currently fails in unrelated
    `plugins::manager::tests::list_marketplaces_ignores_installed_roots_missing_from_config`;
    rerunning that single test fails the same way at
    `core/src/plugins/manager_tests.rs:1692`.
    
    ---------
    
    Co-authored-by: pash <pash@openai.com>
  • add token-based tool deferral behind feature flag (#18097)
    add new `tool_search_always_defer_mcp_tools` feature flag that always
    defers all mcp tools rather than deferring once > 100 deferrable tools.
    
    add new tests, also move `mcp_exposure` tests into dedicated file rather
    than polluting `codex_tests`.
  • Add server-level approval defaults for custom MCP servers (#17843)
    ## Summary
    - Add `default_tools_approval_mode` support for custom MCP server
    configs, matching the existing `codex_apps` behavior
    - Apply approval precedence as per-tool override, then server default,
    then `auto`
    - Update config serialization, CLI display, schema generation, docs, and
    tests
    
    ## Testing
    - `cargo check -p codex-config`
    - `cargo check -p codex-core`
    - `just write-config-schema`
    - `just fmt`
    - `cargo test -p codex-config`
    - Targeted `codex-core` tests for config parsing, config writes, and MCP
    approval precedence
    - `just fix -p codex-config -p codex-core`
  • [1/8] Add MCP server environment config (#18085)
    ## Summary
    - Add an MCP server environment setting with local as the default.
    - Thread the default through config serialization, schema generation,
    and existing config fixtures.
    
    ## Stack
    ```text
    o  #18027 [8/8] Fail exec client operations after disconnect
    │
    o  #18025 [7/8] Cover MCP stdio tests with executor placement
    │
    o  #18089 [6/8] Wire remote MCP stdio through executor
    │
    o  #18088 [5/8] Add executor process transport for MCP stdio
    │
    o  #18087 [4/8] Abstract MCP stdio server launching
    │
    o  #18020 [3/8] Add pushed exec process events
    │
    o  #18086 [2/8] Support piped stdin in exec process API
    │
    @  #18085 [1/8] Add MCP server environment config
    │
    o  main
    ```
    
    Co-authored-by: Codex <noreply@openai.com>
  • [codex][mcp] Add resource uri meta to tool call item. (#17831)
    - [x] Add resource uri meta to tool call item so that the app-server
    client can start prefetching resources immediately without loading mcp
    server status.
  • Update ToolSearch to be enabled by default (#17854)
    ## Summary
    - Promote `Feature::ToolSearch` to `Stable` and enable it in the default
    feature set
    - Update feature tests and tool registry coverage to match the new
    default
    - Adjust the search-tool integration test to assert the default-on path
    and explicit disable fallback
    
    ## Testing
    - `just fmt`
    - `cargo test -p codex-features`
    - `cargo test -p codex-core --test all search_tool`
    - `cargo test -p codex-tools`
  • register all mcp tools with namespace (#17404)
    stacked on #17402.
    
    MCP tools returned by `tool_search` (deferred tools) get registered in
    our `ToolRegistry` with a different format than directly available
    tools. this leads to two different ways of accessing MCP tools from our
    tool catalog, only one of which works for each. fix this by registering
    all MCP tools with the namespace format, since this info is already
    available.
    
    also, direct MCP tools are registered to responsesapi without a
    namespace, while deferred MCP tools have a namespace. this means we can
    receive MCP `FunctionCall`s in both formats from namespaces. fix this by
    always registering MCP tools with namespace, regardless of deferral
    status.
    
    make code mode track `ToolName` provenance of tools so it can map the
    literal JS function name string to the correct `ToolName` for
    invocation, rather than supporting both in core.
    
    this lets us unify to a single canonical `ToolName` representation for
    each MCP tool and force everywhere to use that one, without supporting
    fallbacks.
  • Add supports_parallel_tool_calls flag to included mcps (#17667)
    ## Why
    
    For more advanced MCP usage, we want the model to be able to emit
    parallel MCP tool calls and have Codex execute eligible ones
    concurrently, instead of forcing all MCP calls through the serial block.
    
    The main design choice was where to thread the config. I made this
    server-level because parallel safety depends on the MCP server
    implementation. Codex reads the flag from `mcp_servers`, threads the
    opted-in server names into `ToolRouter`, and checks the parsed
    `ToolPayload::Mcp { server, .. }` at execution time. That avoids relying
    on model-visible tool names, which can be incomplete in
    deferred/search-tool paths or ambiguous for similarly named
    servers/tools.
    
    ## What was added
    
    Added `supports_parallel_tool_calls` for MCP servers.
    
    Before:
    
    ```toml
    [mcp_servers.docs]
    command = "docs-server"
    ```
    
    After:
    
    ```toml
    [mcp_servers.docs]
    command = "docs-server"
    supports_parallel_tool_calls = true
    ```
    
    MCP calls remain serial by default. Only tools from opted-in servers are
    eligible to run in parallel. Docs also now warn to enable this only when
    the server’s tools are safe to run concurrently, especially around
    shared state or read/write races.
    
    ## Testing
    
    Tested with a local stdio MCP server exposing real delay tools. The
    model/Responses side was mocked only to deterministically emit two MCP
    calls in the same turn.
    
    Each test called `query_with_delay` and `query_with_delay_2` with `{
    "seconds": 25 }`.
    
    | Build/config | Observed | Wall time |
    | --- | --- | --- |
    | main with flag enabled | serial | `58.79s` |
    | PR with flag enabled | parallel | `31.73s` |
    | PR without flag | serial | `56.70s` |
    
    PR with flag enabled showed both tools start before either completed;
    main and PR-without-flag completed the first delay before starting the
    second.
    
    Also added an integration test.
    
    Additional checks:
    
    - `cargo test -p codex-tools` passed
    - `cargo test -p codex-core
    mcp_parallel_support_uses_exact_payload_server` passed
    - `git diff --check` passed
  • [mcp] Expand tool search to custom MCPs. (#16944)
    - [x] Expand tool search to custom MCPs.
    - [x] Rename several variables/fields to be more generic.
    
    Updated tool & server name lifecycles:
    
    **Raw Identity**
    
    ToolInfo.server_name is raw MCP server name.
    ToolInfo.tool.name is raw MCP tool name.
    MCP calls route back to raw via parse_tool_name() returning
    (tool.server_name, tool.tool.name).
    mcpServerStatus/list now groups by raw server and keys tools by
    Tool.name: mod.rs:599
    App-server just forwards that grouped raw snapshot:
    codex_message_processor.rs:5245
    
    **Callable Names**
    
    On list-tools, we create provisional callable_namespace / callable_name:
    mcp_connection_manager.rs:1556
    For non-app MCP, provisional callable name starts as raw tool name.
    For codex-apps, provisional callable name is sanitized and strips
    connector name/id prefix; namespace includes connector name.
    Then qualify_tools() sanitizes callable namespace + name to ASCII alnum
    / _ only: mcp_tool_names.rs:128
    Note: this is stricter than Responses API. Hyphen is currently replaced
    with _ for code-mode compatibility.
    
    **Collision Handling**
    
    We do initially collapse example-server and example_server to the same
    base.
    Then qualify_tools() detects distinct raw namespace identities behind
    the same sanitized namespace and appends a hash to the callable
    namespace: mcp_tool_names.rs:137
    Same idea for tool-name collisions: hash suffix goes on callable tool
    name.
    Final list_all_tools() map key is callable_namespace + callable_name:
    mcp_connection_manager.rs:769
    
    **Direct Model Tools**
    
    Direct MCP tool declarations use the full qualified sanitized key as the
    Responses function name.
    The raw rmcp Tool is converted but renamed for model exposure.
    
    **Tool Search / Deferred**
    
    Tool search result namespace = final ToolInfo.callable_namespace:
    tool_search.rs:85
    Tool search result nested name = final ToolInfo.callable_name:
    tool_search.rs:86
    Deferred tool handler is registered as "{namespace}:{name}":
    tool_registry_plan.rs:248
    When a function call comes back, core recombines namespace + name, looks
    up the full qualified key, and gets the raw server/tool for MCP
    execution: codex.rs:4353
    
    **Separate Legacy Snapshot**
    
    collect_mcp_snapshot_from_manager_with_detail() still returns a map
    keyed by qualified callable name.
    mcpServerStatus/list no longer uses that; it uses
    McpServerStatusSnapshot, which is raw-inventory shaped.
  • Forward app-server turn clientMetadata to Responses (#16009)
    ## Summary
    App-server v2 already receives turn-scoped `clientMetadata`, but the
    Rust app-server was dropping it before the outbound Responses request.
    This change keeps the fix lightweight by threading that metadata through
    the existing turn-metadata path rather than inventing a new transport.
    
    ## What we're trying to do and why
    We want turn-scoped metadata from the app-server protocol layer,
    especially fields like Hermes/GAAS run IDs, to survive all the way to
    the actual Responses API request so it is visible in downstream
    websocket request logging and analytics.
    
    The specific bug was:
    - app-server protocol uses camelCase `clientMetadata`
    - Responses transport already has an existing turn metadata carrier:
    `x-codex-turn-metadata`
    - websocket transport already rewrites that header into
    `request.request_body.client_metadata["x-codex-turn-metadata"]`
    - but the Rust app-server never parsed or stored `clientMetadata`, so
    nothing from the app-server request was making it into that existing
    path
    
    This PR fixes that without adding a new header or a second metadata
    channel.
    
    ## How we did it
    ### Protocol surface
    - Add optional `clientMetadata` to v2 `TurnStartParams` and
    `TurnSteerParams`
    - Regenerate the JSON schema / TypeScript fixtures
    - Update app-server docs to describe the field and its behavior
    
    ### Runtime plumbing
    - Add a dedicated core op for app-server user input carrying turn-scoped
    metadata: `Op::UserInputWithClientMetadata`
    - Wire `turn/start` and `turn/steer` through that op / signature path
    instead of dropping the metadata at the message-processor boundary
    - Store the metadata in `TurnMetadataState`
    
    ### Transport behavior
    - Reuse the existing serialized `x-codex-turn-metadata` payload
    - Merge the new app-server `clientMetadata` into that JSON additively
    - Do **not** replace built-in reserved fields already present in the
    turn metadata payload
    - Keep websocket behavior unchanged at the outer shape level: it still
    sends only `client_metadata["x-codex-turn-metadata"]`, but that JSON
    string now contains the merged fields
    - Keep HTTP fallback behavior unchanged except that the existing
    `x-codex-turn-metadata` header now includes the merged fields too
    
    ### Request shape before / after
    Before, a websocket `response.create` looked like:
    ```json
    {
      "type": "response.create",
      "client_metadata": {
        "x-codex-turn-metadata": "{\"session_id\":\"...\",\"turn_id\":\"...\"}"
      }
    }
    ```
    Even if the app-server caller supplied `clientMetadata`, it was not
    represented there.
    
    After, the same request shape is preserved, but the serialized payload
    now includes the new turn-scoped fields:
    ```json
    {
      "type": "response.create",
      "client_metadata": {
        "x-codex-turn-metadata": "{\"session_id\":\"...\",\"turn_id\":\"...\",\"fiber_run_id\":\"fiber-start-123\",\"origin\":\"gaas\"}"
      }
    }
    ```
    
    ## Validation
    ### Targeted tests added / updated
    - protocol round-trip coverage for `clientMetadata` on `turn/start` and
    `turn/steer`
    - protocol round-trip coverage for `Op::UserInputWithClientMetadata`
    - `TurnMetadataState` merge test proving client metadata is added
    without overwriting reserved built-in fields
    - websocket request-shape test proving outbound `response.create`
    contains merged metadata inside
    `client_metadata["x-codex-turn-metadata"]`
    - app-server integration tests proving:
    - `turn/start` forwards `clientMetadata` into the outbound Responses
    request path
      - websocket warmup + real turn request both behave correctly
      - `turn/steer` updates the follow-up request metadata
    
    ### Commands run
    - `just write-app-server-schema`
    - `cargo test -p codex-app-server-protocol`
    - `cargo test -p codex-protocol`
    - `cargo test -p codex-core
    turn_metadata_state_merges_client_metadata_without_replacing_reserved_fields
    --lib`
    - `cargo test -p codex-core --test all
    responses_websocket_preserves_custom_turn_metadata_fields`
    - `cargo test -p codex-app-server --test all client_metadata`
    - `cargo test -p codex-app-server --test all
    turn_start_forwards_client_metadata_to_responses_websocket_request_body_v2
    -- --nocapture`
    - `just fmt`
    - `just fix -p codex-core -p codex-protocol -p codex-app-server-protocol
    -p codex-app-server`
    - `just fix -p codex-exec -p codex-tui-app-server`
    - `just argument-comment-lint`
    
    ### Full suite note
    `cargo test` in `codex-rs` still fails in:
    -
    `suite::v2::turn_interrupt::turn_interrupt_resolves_pending_command_approval_request`
    
    I verified that same failure on a clean detached `HEAD` worktree with an
    isolated `CARGO_TARGET_DIR`, so it is not caused by this patch.