36 Commits

  • feat(app-server): add history_mode to thread (#29927)
    ## Description
    
    This PR adds a new `historyMode = "legacy" | "paginated"` to `Thread`.
    This will be stored in `SessionMeta` in the JSONL rollout file and as a
    new column in the SQLite thread_metadata table, and exposed on
    `thread/start` and on the `Thread` object in app-server.
    
    ## What changed
    
    - Added canonical `ThreadHistoryMode` with `legacy` and `paginated`,
    defaulting old and new SessionMeta to `legacy`.
    - Carried `history_mode` through core session config, ThreadStore stored
    metadata, local/in-memory stores, rollout metadata extraction, and the
    existing SQLite `threads` table.
    - Added experimental `historyMode` to app-server v2 `Thread` and
    `thread/start`.
    - Made paginated stored threads metadata-discoverable but unsupported
    for legacy full-history reads, `load_history`, live resume, and create
    paths.
    - Regenerated app-server schema fixtures and added
    protocol/state/thread-store/app-server coverage for persistence and
    fail-closed behavior.
    
    ## Compatibility floor
    Because users may be running various versions of Codex binaries on the
    same machine (TUI, Codex App, etc.), we will need to establish a
    compatibility floor for upcoming paginated threads, which will change
    how thread storage reads and writes work.
    
    The overall plan here:
    ```
    Release N:
    - Add historyMode to SessionMeta / Thread / SQLite metadata.
    - Teach binaries to understand paginated threads.
    - If a binary sees `historyMode="paginated"` but does not support the paginated contract, it refuses to resume/mutate the thread.
    - Default remains `"legacy"`.
    
    Release N+1:
    - First-party clients start opting into paginated threads where appropriate.
    - Internal dogfood / staged rollout.
    - Measure old-client usage and paginated-thread unsupported errors.
    
    Release N+2:
    - Only after Release N+ is overwhelmingly deployed, make paginated the default.
    - Accept that a small tail of N-1-or-older binaries may not understand paginated threads.
    ```
    
    The important behavior change is fail-closed handling for a binary that
    encounters a persisted `paginated` thread before it knows how to fully
    support paginated history. In app-server, if a thread is `paginated`, we
    will:
    
    - allow metadata-only discovery paths like `thread/list` and
    `thread/read(includeTurns=false)`, so clients can still see the thread
    and inspect its `historyMode`
    - reject legacy full-history/live-thread paths like
    `thread/read(includeTurns=true)` and `thread/resume` with an unsupported
    JSON-RPC error
    - avoid silently treating an unknown or future `historyMode` as `legacy`
    
    Under the hood, the ThreadStore layer also rejects legacy operations
    that would need to load or replay the full thread history for a
    paginated thread. That gives us the behavior we want for Release N:
    future paginated threads are visible, but this binary fails closed
    instead of trying to operate on them as if they were legacy threads.
  • protocol: separate app and exec RPC ownership (#29714)
    ## Why
    
    The app-server and exec-server expose separate JSON-RPC APIs, but
    exec-server currently sources its serialized protocol and envelope types
    through app-server-oriented code. Giving each API an explicit owner
    makes the crate boundary legible without introducing shared generic
    envelopes.
    
    ## What changed
    
    - Added `codex-exec-server-protocol` to own exec DTOs, process IDs, and
    JSON-RPC envelopes.
    - Updated exec-server clients, transports, handlers, and tests to use
    the new crate.
    - Exposed app-server's existing JSON-RPC types through a public `rpc`
    module while retaining root re-exports.
    - Preserved existing wire shapes, including exec `PathUri` behavior.
    
    ## Stack
    
    This is PR 1 of 6. Next: [PR
    #29721](https://github.com/openai/codex/pull/29721), which moves auth
    mode below the app wire boundary.
    
    ## Validation
    
    - Exec-server protocol and server coverage passed in the focused
    protocol test runs.
    - App-server protocol schema fixtures passed.
  • Make selected plugin roots URI-native (#28918)
    ## Why
    
    Selected capability roots belong to the executor filesystem, not the
    app-server host. Converting their path strings into the host's native
    `Path` breaks whenever the two machines use different path conventions,
    such as a Windows executor behind a Unix app-server.
    
    This PR establishes `PathUri` as the selected-plugin boundary so the
    executor remains authoritative for its paths.
    
    ## What changed
    
    - Require `selectedCapabilityRoots[].location.path` to be a canonical
    `file:` URI and deserialize it directly as `PathUri`; native path
    strings are rejected.
    - Update the app-server schema, generated TypeScript, examples, and
    request coverage for the URI contract.
    - Keep selected roots, resolved plugin locations, manifest paths, and
    manifest resources as `PathUri`.
    - Inspect and read plugin roots and manifests only through the selected
    environment's `ExecutorFileSystem`.
    - Parse executor manifests with the shared URI-native parser from #29620
    instead of projecting them onto the host filesystem.
    - Enforce resource containment lexically and preserve the root URI's
    POSIX or Windows path convention.
    - Cover foreign Windows plugin roots and URI-native manifest resources.
    
    ```text
    thread/start
      selectedCapabilityRoots[].location.path = "file:///C:/plugins/demo"
                                  | PathUri
                                  v
                        ExecutorFileSystem
                                  |
                                  +--> plugin.json
                                  +--> manifest resources
    ```
    
    This PR stops at the shared selected-plugin representation. The next two
    PRs remove the remaining host-path projections in the skill and MCP
    consumers.
    
    ## Stack
    
    1. #29614 — add lexical `PathUri` containment.
    2. #29620 — share URI-native manifest path resolution.
    3. **This PR** — keep selected plugin roots and resources URI-native.
    4. #29626 — load executor skills without host path conversion.
    5. #29628 — resolve executor MCP working directories without host path
    conversion.
  • chore(core) rm AskForApproval::OnFailure (#28418)
    ## Summary
    Deletes the OnFailure variant of the `AskForApproval` enum. This option
    has been deprecated since #11631.
    
    ## Testing
    - [x] Tests pass
  • Simplify multi-agent mode controls (#29324)
    ## Why
    
    Multi-agent delegation policy was split across `multiAgentMode`,
    `features.multi_agent_mode`, and `usage_hint_enabled`. These controls
    could disagree: a requested mode could be downgraded by the feature
    flag, and disabling usage hints also disabled mode instructions.
    
    Some clients also need multi-agent tools without adding
    delegation-policy text to model context. The previous two-mode API could
    not express that directly.
    
    ## What changed
    
    `multiAgentMode` is now the only live delegation-policy control:
    
    | Mode | Behavior |
    | --- | --- |
    | `none` | Keep multi-agent tools available without adding mode
    instructions. |
    | `explicitRequestOnly` | Only delegate after an explicit user request.
    |
    | `proactive` | Delegate when parallel work materially improves speed or
    quality. |
    
    - new threads default to `explicitRequestOnly`; omitting the mode on
    later turns keeps the current value
    - thread start, resume, fork, and settings responses always report the
    concrete current mode instead of `null`
    - mode selection remains sticky across turns and resume
    - usage-hint text no longer controls whether mode instructions apply
    - `features.multi_agent_mode` and `usage_hint_enabled` remain accepted
    as ignored compatibility settings so existing configs continue to load
    - app-server documentation and generated schemas describe the three-mode
    API
    
    ## Tests
    
    - `just test -p codex-core multi_agent_mode`
    - `just test -p codex-core multi_agent_v2_config_from_feature_table`
    - `just test -p codex-core spawn_agent_description`
    - `just test -p codex-features`
    - `just test -p codex-app-server-protocol`
    - `just test -p codex-app-server multi_agent_mode`
  • Expose thread-level multi-agent mode (#28792)
    ## Why
    
    Once multi-agent mode can be selected per turn, clients also need to
    choose the initial selection when creating a thread and observe that
    selection through lifecycle and settings APIs.
    
    The selected value is intentionally distinct from the effective
    model-visible value: no client selection is represented as `null`, even
    though an eligible multi-agent v2 turn derives `explicitRequestOnly` as
    its effective default.
    
    ## What changed
    
    - Add the optional experimental `thread/start.multiAgentMode` parameter
    and pass it through thread creation.
    - Preserve an omitted initial value as an unset selection rather than
    eagerly storing `explicitRequestOnly`.
    - Apply an explicit `thread/start` selection to the first turn through
    the session configuration established at thread creation.
    - Restore the latest persisted effective mode as the selected baseline
    on cold resume when rollout history contains one.
    - Inherit the optional selected mode from a loaded parent when creating
    related runtime threads.
    - Return the current selected `multiAgentMode` from `thread/start`,
    `thread/resume`, `thread/fork`, and thread settings, using `null` when
    no mode is selected.
    - Keep lifecycle reporting independent from model capability and feature
    eligibility; core turn construction remains responsible for calculating
    and persisting the effective mode.
    
    ## Not covered
    
    - Clearing an existing loaded-session selection back to unset through
    `turn/start`; omitted or `null` currently retains the session's
    selection.
    - A TUI control, slash command, or `config.toml` preference.
    
    ## Verification
    
    - `CARGO_INCREMENTAL=0 just test -p codex-app-server-protocol`
    - `CARGO_INCREMENTAL=0 just test -p codex-app-server multi_agent_mode`
    
    The focused app-server coverage verifies explicit `thread/start`
    initialization, first-turn prompting, nullable reporting for an omitted
    selection, and retention of selections that are not currently
    runtime-eligible.
    
    ## Stack
    
    Stacked on #28685. This PR contains only the thread initialization and
    lifecycle/settings API layer.
  • app-server: preserve target-native environment cwd (#28146)
    ## Why
    
    app-server may run on a different OS from the selected exec-server
    environment. Parsing that environment’s cwd with the Codex host’s path
    rules prevents thread startup.
    
    ## What
    
    Carry environment cwd values as `LegacyAppPathString` at the app-server
    boundary and `PathUri` internally. Existing tool-call schemas and
    relative-path behavior stay host-native; remaining local-only consumers
    convert explicitly and leave follow-up TODOs.
    
    The Wine integration test verifies app-server can start a thread and
    complete an ordinary turn with a Windows environment cwd from Linux.
    
    ## Validation
    
    - `bazel test //codex-rs/core/tests/remote_env_windows:smoke-test
    --test_output=errors`
    - focused app-server environment-selection and protocol schema tests
    - scoped Clippy for `codex-core` and `codex-app-server-protocol`
  • Expose explicit dynamic tool namespaces in thread start (#27371)
    Stacked on #27365.
    
    ## Stack note
    
    [#27365](https://github.com/openai/codex/pull/27365) kept `thread/start`
    unchanged and converted its input in `thread_processor`. This PR updates
    `thread/start` to accept explicit functions and namespaces directly.
    
    Legacy per-tool arrays are still accepted and converted while reading
    the request. As a result, `thread_processor` can validate and pass the
    tools through directly, which is why some code added in #27365 is
    removed here.
    
    ## Why
    
    `thread/start.dynamicTools` still repeats namespace data on each
    function even though core now stores explicit namespace groups. The
    request API should use the same shape so each namespace has one
    description and one member list.
    
    ## What changed
    
    - Accept top-level functions and explicit namespace objects in
    `dynamicTools`.
    - Continue accepting fully legacy flat arrays, including
    `exposeToContext`.
    - Reject arrays that mix legacy and canonical entries.
    - Reuse the protocol types directly and remove the temporary app-server
    adapter.
    - Update validation, docs, the test client, and generated schemas.
    
    ## Test plan
    
    - `just test -p codex-app-server-protocol`
    - `just test -p codex-app-server
    dynamic_tool_call_round_trip_sends_text_content_items_to_model`
    - `just test -p codex-app-server
    thread_start_normalizes_legacy_dynamic_tools_into_model_request`
    - `just test -p codex-app-server
    thread_start_rejects_mixed_dynamic_tool_formats`
    - `just test -p codex-app-server
    thread_start_rejects_hidden_dynamic_tools_without_namespace`
  • [codex-analytics] add extensible feature thread sources (#27063)
    ## Why
    - `ThreadSource` currently defines a closed set of core-owned values
    - Product features also create threads for background or scheduled work
    - Adding every product-specific value to the core enum would require
    repeated `codex-rs` protocol changes
    - Feature-backed values let product callers provide precise attribution
    while preserving the existing core classifications
    
    ## What Changed
    - Adds `ThreadSource::Feature(String)` for app-owned thread source
    values
    - Represents all app-server v2 thread sources as scalar strings, so a
    feature source is supplied as `"automation"`
    - Persists and emits the feature's plain string label, so `"automation"`
    produces `thread_source="automation"` in analytics
    - Keeps `user`, `subagent`, and `memory_consolidation` as explicit
    core-owned values and regenerates the app-server schemas and TypeScript
    bindings
    
    ## Verification
    - `just write-app-server-schema`
    - `cargo check --workspace`
    - `just test -p codex-protocol
    feature_thread_source_serializes_as_its_app_owned_label`
    - `just test -p codex-app-server-protocol
    thread_sources_round_trip_as_scalar_labels`
    - `cargo test -p codex-analytics
    thread_initialized_event_serializes_expected_shape`
    - `just fmt`
  • Load selected executor skills through extensions (#27184)
    ## Why
    
    CCA is moving toward a split runtime where the orchestrator may not have
    a filesystem, while executors can expose preinstalled plugins and
    skills. A thread therefore needs to select capabilities without asking
    app-server or core to interpret executor-owned paths through the
    orchestrator's filesystem.
    
    The longer-term model is broader than executor skills:
    
    - A plugin is a bundle of skills, MCP servers, connectors/apps, and
    hooks.
    - A plugin root can be local, executor-owned, or hosted by a backend.
    - Components inside one plugin can use different access and execution
    mechanisms. A skill may be read from a filesystem or through backend
    tools; an HTTP MCP server can run without an executor; a stdio MCP
    server or hook needs an execution environment.
    - Core should carry generic extension initialization data. The extension
    that owns a component should discover it, expose it to the model, and
    invoke it through the appropriate runtime.
    
    This PR establishes that architecture through one complete vertical:
    selecting a root on an executor, discovering the skills beneath it,
    exposing those skills to the model, and reading an explicitly invoked
    `SKILL.md` through the same executor.
    
    ## Contract
    
    `thread/start` gains an experimental `selectedCapabilityRoots` field:
    
    ```json
    {
      "selectedCapabilityRoots": [
        {
          "id": "deploy-plugin@1",
          "location": {
            "type": "environment",
            "environmentId": "workspace",
            "path": "/opt/codex/plugins/deploy"
          }
        }
      ]
    }
    ```
    
    The root is intentionally not classified as a "plugin" or "skill" in the
    API. It can point at a standalone skill, a directory containing several
    skills, or a plugin containing skills and other components. This PR only
    teaches the skills extension how to consume it; later extensions can
    resolve MCP, connector, and hook components from the same selection.
    
    The platform-supplied `id` is stable selection identity. The location
    says which runtime owns the root and gives that runtime an opaque path.
    App-server does not inspect or canonicalize the path.
    
    ## What changed
    
    ### Generic thread extension initialization
    
    App-server converts selected roots into `ExtensionDataInit`. Core
    carries that generic initialization value until the final thread ID is
    known, then creates thread-scoped `ExtensionData` before lifecycle
    contributors run.
    
    This keeps `Session` and core independent of the capability-selection
    contract. The initialization value is consumed during construction; it
    is not retained as another long-lived `Session` field.
    
    ### Executor-backed skills
    
    The skills extension now owns an `ExecutorSkillProvider` that:
    
    - resolves the selected environment through `EnvironmentManager`
    - discovers, canonicalizes, and reads skills through that environment's
    `ExecutorFileSystem`
    - contributes the bounded selected-skill catalog as stable developer
    context
    - reads an explicitly invoked skill body through the authority that
    listed it
    - warns when an environment or root is unavailable
    - never falls back to the orchestrator filesystem for an executor-owned
    root
    
    Skill catalog and instruction fragments have hard byte bounds, which
    also bound them below the 10K-token per-item context limit. If a
    selected executor skill has the same name as a legacy local skill, the
    executor selection owns that invocation and the local body is not
    injected a second time.
    
    Existing local and bundled skill loading remains in place. Omitting
    `selectedCapabilityRoots` therefore preserves current local-only
    behavior.
    
    ## Current semantics
    
    - Only environment-owned locations are represented in this first
    contract.
    - Roots are resolved by the destination extension, not by app-server or
    core.
    - An unavailable executor or invalid root produces a warning and no
    capabilities from that root; it does not trigger a local-filesystem
    fallback.
    - Selection applies to a newly started active thread.
    - MCP servers, connectors, and hooks beneath a selected plugin root are
    not activated yet.
    - Selection is not yet persisted or inherited across resume, fork, or
    subagent creation. Existing local capabilities continue to behave as
    they do today in those flows.
    
    ## Planned vertical follow-ups
    
    1. **Hosted HTTP MCP:** add an extension-backed HTTP MCP source that
    works without an executor, then replace the special-purpose MCP plugins
    loader with that implementation.
    2. **Executor MCP:** register and execute stdio MCP servers through the
    environment that owns the selected plugin root.
    3. **Backend skills:** add a hosted skill source whose catalog and
    bodies are accessed through extension tools rather than a filesystem.
    4. **Connectors and hooks:** activate those components through their
    owning extensions, using the same selected-root boundary and
    component-specific runtime.
    5. **Durable selection:** define the desired-selection lifecycle,
    persist it, and make resume, fork, and subagent inheritance explicit
    rather than accidental.
    6. **Local convergence:** incrementally route existing local plugin,
    skill, and MCP loading through the same extension model while preserving
    current local behavior.
    
    Each follow-up remains reviewable as an end-to-end capability. The
    platform selects roots, generic thread extension data carries the
    selection, and the owning extension resolves and operates its component.
    
    ## Verification
    
    Coverage added for:
    
    - app-server end-to-end discovery and explicit invocation of a skill
    inside an executor-selected plugin root
    - exclusive invocation when a selected executor skill collides with a
    local skill name
    - executor filesystem authority for discovery, canonicalization, and
    reads
    - thread extension initialization before lifecycle contributors run
    - stable executor catalog context, explicit invocation, context
    rebuilding, hidden skills, and preserved host/remote catalog behavior
    
    Targeted protocol, core-skills, skills-extension, core lifecycle, and
    app-server executor-skill tests were run during development.
  • app-server: use permission ids and runtime workspace roots (#22611)
    ## Why
    
    This PR builds on [#22610](https://github.com/openai/codex/pull/22610)
    and is the app-server side of the migration from mutable per-turn
    `SandboxPolicy` replacement toward selecting immutable permission
    profiles by id plus mutable runtime workspace roots.
    
    Once permission profiles can carry their own immutable
    `workspace_roots`, app-server no longer needs to mutate the selected
    `PermissionProfile` just to represent thread-specific filesystem
    context. The mutable part now lives on the thread as explicit
    `runtimeWorkspaceRoots`, while `:workspace_roots` remains symbolic until
    the sandbox is realized for a turn.
    
    ## What Changed
    
    - Replaced the v2 permission-selection wrapper surface with plain
    profile ids for `thread/start`, `thread/resume`, `thread/fork`, and
    `turn/start`.
    - Removed the API surface for profile modifications
    (`PermissionProfileSelectionParams`,
    `PermissionProfileModificationParams`,
    `ActivePermissionProfileModification`).
    - Added experimental `runtimeWorkspaceRoots` fields to the thread
    lifecycle and turn-start APIs.
    - Threaded runtime workspace roots through core session/thread
    snapshots, turn overrides, app-server request handling, and command
    execution permission resolution.
    - Kept session permission state symbolic so later runtime root updates
    and cwd-only implicit-root retargeting rebind `:workspace_roots`
    correctly.
    - Updated the embedded clients just enough to send and restore the new
    thread state.
    - Refreshed the generated schema/TypeScript artifacts and the app-server
    README to match the new contract.
    
    ## Verification
    
    Targeted coverage for this layer lives in:
    
    - `codex-rs/app-server-protocol/src/protocol/v2/tests.rs`
    - `codex-rs/app-server/tests/suite/v2/thread_start.rs`
    - `codex-rs/app-server/tests/suite/v2/thread_resume.rs`
    - `codex-rs/app-server/tests/suite/v2/turn_start.rs`
    - `codex-rs/core/src/session/tests.rs`
    
    The key regression checks exercise that:
    
    - `runtimeWorkspaceRoots` resolve against the effective cwd on thread
    start.
    - Profile-declared workspace roots are excluded from the runtime
    workspace roots returned by app-server.
    - A turn-level runtime workspace-root update persists onto the thread
    and is returned by `thread/resume`.
    - A named permission profile selected on one turn remains symbolic so a
    later runtime-root-only turn update changes the actual sandbox writes.
    - A cwd-only turn update retargets the implicit runtime cwd root while
    preserving additional runtime roots.
    - The protocol fixtures and generated client artifacts stay in sync with
    the string-based permission selection contract.
    
    
    
    
    
    
    
    
    
    
    
    ---
    [//]: # (BEGIN SAPLING FOOTER)
    Stack created with [Sapling](https://sapling-scm.com). Best reviewed
    with [ReviewStack](https://reviewstack.dev/openai/codex/pull/22611).
    * #22612
    * __->__ #22611
  • 2- Use string service tiers in session protocol (#20971)
    ## Summary
    - break service tier session/op/app-server protocol fields from the
    closed enum to string tier ids
    - send the service tier string directly through model requests, prewarm,
    compaction, memories, and TUI/app-server turn starts
    - regenerate app-server protocol JSON/TypeScript schemas, removing the
    standalone ServiceTier TS enum
    
    ## Verification
    - just fmt
    - cargo check -p codex-core -p codex-app-server -p codex-tui
    - just write-app-server-schema
    
    ---------
    
    Co-authored-by: Codex <noreply@openai.com>
  • [codex-analytics] rework thread_source for thread analytics (#20949)
    ## Summary
    - make `thread_source` an explicit optional thread-level field on
    `thread/start`, `thread/fork`, and returned thread payloads
    - persist `thread_source` in rollout/session metadata so resumed live
    threads retain the original value
    - replace the old best-effort `session_source` -> `thread_source`
    mapping with an explicit caller-supplied analytics classification
    
    ## Why
    Before this change, analytics `thread_source` was populated by a
    best-effort mapping from `session_source`. `session_source` describes
    the runtime/client surface, not the actual thread-level origin, so that
    projection was not accurate enough to distinguish cases such as `user`,
    `subagent`, `memory_consolidation`, and future thread origins reliably.
    
    Making `thread_source` explicit keeps one thread-level analytics field
    while letting callers provide the real classification directly instead
    of recovering it indirectly from `session_source`.
    
    ## Impact
    For new analytics events, `thread_source` now reflects the explicit
    thread-level classification supplied by the caller rather than an
    inferred value derived from `session_source`. Existing protocol fields
    remain optional; callers that omit `threadSource` now produce `null`
    instead of a best-effort inferred value.
    
    ## Validation
    - `just write-app-server-schema`
    - `cargo test -p codex-analytics -p codex-core -p
    codex-app-server-protocol --no-run`
    - `cargo test -p codex-app-server-protocol
    generated_ts_optional_nullable_fields_only_in_params`
    - `cargo test -p codex-analytics
    thread_initialized_event_serializes_expected_shape`
    - `cargo test -p codex-core
    resume_stopped_thread_from_rollout_preserves_thread_source`
  • app-server-protocol: mark permission profiles experimental (#19899)
    ## Why
    
    `PermissionProfile` is now the canonical internal permissions
    representation, but the app-server wire shape is still intentionally
    unstable while the migration continues. Stable app-server clients should
    not see or generate code for these fields until the wire format settles.
    
    ## What changed
    
    - Marks every app-server v2 field that sends `PermissionProfile` as
    experimental, including `command/exec`, `thread/start`, `thread/resume`,
    `thread/fork`, and `turn/start` request/response payloads.
    - Enables per-field experimental inspection for `command/exec`, so
    `permissionProfile` is gated without making the entire method
    experimental.
    - Fixes the generated TypeScript schema filter to be comment-aware. The
    previous scanner treated apostrophes inside doc comments as string
    delimiters, so some experimental fields leaked into stable TypeScript
    even though stable JSON was filtered correctly.
    
    ## Verification
    
    - `cargo test -p codex-app-server-protocol`
    
    
    
    
    
    
    
    
    
    
    ---
    [//]: # (BEGIN SAPLING FOOTER)
    Stack created with [Sapling](https://sapling-scm.com). Best reviewed
    with [ReviewStack](https://reviewstack.dev/openai/codex/pull/19899).
    * #19900
    * __->__ #19899
  • permissions: remove cwd special path (#19841)
    ## Why
    
    The experimental `PermissionProfile` API had both `:cwd` and
    `:project_roots` special filesystem paths, which made the permission
    root ambiguous. This PR removes the unstable `current_working_directory`
    special path before the permissions API is stabilized, so callers use
    `:project_roots` for symbolic project-root access.
    
    ## What changed
    
    - Removes `FileSystemSpecialPath::CurrentWorkingDirectory` from protocol
    and app-server protocol models, plus regenerated app-server
    JSON/TypeScript schemas.
    - Replaces internal `:cwd` permission entries with `:project_roots`
    entries.
    - Keeps the existing cwd-update behavior for legacy-shaped
    workspace-write profiles, while removing the deleted
    `CurrentWorkingDirectory` case from that compatibility path.
    - Keeps `PermissionProfile::workspace_write()` as the reusable symbolic
    workspace-write helper, with docs noting that `:project_roots` entries
    resolve at enforcement time.
    - Updates app-server docs/examples and approval UI labeling to stop
    advertising `:cwd` as a permission token.
    
    ## Compatibility
    
    Persisted rollout items may contain the old
    `{"kind":"current_working_directory"}` tag from earlier experimental
    `permissionProfile` snapshots. This PR keeps that tag as a
    deserialize-only alias for `ProjectRoots { subpath: None }`, while
    continuing to serialize only the new `project_roots` tag.
    
    ## Follow-up
    
    This PR intentionally does not introduce an explicit project-root set on
    `SessionConfiguration` or runtime sandbox resolution. Today, the
    resolver still uses the active cwd as the single implicit project root.
    A follow-up should model project roots separately from tool cwd so
    `:project_roots` entries can resolve against the configured project
    roots, and resolve to no entries when there are no project roots.
    
    ## Verification
    
    - `cargo test -p codex-protocol permissions:: --lib`
    - `cargo test -p codex-app-server-protocol`
    - `cargo test -p codex-sandboxing -p codex-exec-server --lib`
    - `cargo test -p codex-core session_configuration_apply_ --lib`
    - `cargo test -p codex-app-server
    command_exec_permission_profile_project_roots_use_command_cwd --test
    all`
    - `cargo test -p codex-tui
    thread_read_session_state_does_not_reuse_primary_permission_profile
    --lib`
    - `cargo test -p codex-tui
    preset_matching_accepts_workspace_write_with_extra_roots --lib`
    - `cargo test -p codex-config --lib`
  • permissions: make profiles represent enforcement (#19231)
    ## Why
    
    `PermissionProfile` is becoming the canonical permissions abstraction,
    but the old shape only carried optional filesystem and network fields.
    It could describe allowed access, but not who is responsible for
    enforcing it. That made `DangerFullAccess` and `ExternalSandbox` lossy
    when profiles were exported, cached, or round-tripped through app-server
    APIs.
    
    The important model change is that active permissions are now a disjoint
    union over the enforcement mode. Conceptually:
    
    ```rust
    pub enum PermissionProfile {
        Managed {
            file_system: FileSystemSandboxPolicy,
            network: NetworkSandboxPolicy,
        },
        Disabled,
        External {
            network: NetworkSandboxPolicy,
        },
    }
    ```
    
    This distinction matters because `Disabled` means Codex should apply no
    outer sandbox at all, while `External` means filesystem isolation is
    owned by an outside caller. Those are not equivalent to a broad managed
    sandbox. For example, macOS cannot nest Seatbelt inside Seatbelt, so an
    inner sandbox may require the outer Codex layer to use no sandbox rather
    than a permissive one.
    
    ## How Existing Modeling Maps
    
    Legacy `SandboxPolicy` remains a boundary projection, but it now maps
    into the higher-fidelity profile model:
    
    - `ReadOnly` and `WorkspaceWrite` map to `PermissionProfile::Managed`
    with restricted filesystem entries plus the corresponding network
    policy.
    - `DangerFullAccess` maps to `PermissionProfile::Disabled`, preserving
    the “no outer sandbox” intent instead of treating it as a lax managed
    sandbox.
    - `ExternalSandbox { network_access }` maps to
    `PermissionProfile::External { network }`, preserving external
    filesystem enforcement while still carrying the active network policy.
    - Split runtime policies that legacy `SandboxPolicy` cannot faithfully
    express, such as managed unrestricted filesystem plus restricted
    network, stay `Managed` instead of being collapsed into
    `ExternalSandbox`.
    - Per-command/session/turn grants remain partial overlays via
    `AdditionalPermissionProfile`; full `PermissionProfile` is reserved for
    complete active runtime permissions.
    
    ## What Changed
    
    - Change active `PermissionProfile` into a tagged union: `managed`,
    `disabled`, and `external`.
    - Keep partial permission grants separate with
    `AdditionalPermissionProfile` for command/session/turn overlays.
    - Represent managed filesystem permissions as either `restricted`
    entries or `unrestricted`; `glob_scan_max_depth` is non-zero when
    present.
    - Preserve old rollout compatibility by accepting the pre-tagged `{
    network, file_system }` profile shape during deserialization.
    - Preserve fidelity for important edge cases: `DangerFullAccess`
    round-trips as `disabled`, `ExternalSandbox` round-trips as `external`,
    and managed unrestricted filesystem + restricted network stays managed
    instead of being mistaken for external enforcement.
    - Preserve configured deny-read entries and bounded glob scan depth when
    full profiles are projected back into runtime policies, including
    unrestricted replacements that now become `:root = write` plus deny
    entries.
    - Regenerate the experimental app-server v2 JSON/TypeScript schema and
    update the `command/exec` README example for the tagged
    `permissionProfile` shape.
    
    ## Compatibility
    
    Legacy `SandboxPolicy` remains available at config/API boundaries as the
    compatibility projection. Existing rollout lines with the old
    `PermissionProfile` shape continue to load. The app-server
    `permissionProfile` field is experimental, so its v2 wire shape is
    intentionally updated to match the higher-fidelity model.
    
    ## Verification
    
    - `just write-app-server-schema`
    - `cargo check --tests`
    - `cargo test -p codex-protocol permission_profile`
    - `cargo test -p codex-protocol
    preserving_deny_entries_keeps_unrestricted_policy_enforceable`
    - `cargo test -p codex-app-server-protocol
    permission_profile_file_system_permissions`
    - `cargo test -p codex-app-server-protocol serialize_client_response`
    - `cargo test -p codex-core
    session_configured_reports_permission_profile_for_external_sandbox`
    - `just fix`
    - `just fix -p codex-protocol`
    - `just fix -p codex-app-server-protocol`
    - `just fix -p codex-core`
    - `just fix -p codex-app-server`
  • Add sticky environment API and thread state (#18897)
    ## Summary
    - add sticky environment selections to app-server v2 thread/start and
    turn/start request flow
    - carry thread-level selections through core session/thread state
    - add app-server coverage for sticky selections and turn overrides
    
    ## Stack
    1. This PR: API and thread persistence
    2. #18898: config.toml named environment loading
    3. #18899: downstream tool/runtime consumers
    
    ## Validation
    - Not run locally; split only.
    
    ---------
    
    Co-authored-by: Codex <noreply@openai.com>
  • Rebrand approvals reviewer config to auto-review (#18504)
    ### Why
    
    Auto-review is the user-facing name for the approvals reviewer, but the
    config/API value still exposed the old `guardian_subagent` name. That
    made new configs and generated schemas point users at Guardian
    terminology even though the intended product surface is Auto-review.
    
    This PR updates the external `approvals_reviewer` value while preserving
    compatibility for existing configs and clients.
    
    ### What changed
    
    - Makes `auto_review` the canonical serialized value for
    `approvals_reviewer`.
    - Keeps `guardian_subagent` accepted as a legacy alias.
    - Keeps `user` accepted and serialized as `user`.
    - Updates generated config and app-server schemas so
    `approvals_reviewer` includes:
      - `user`
      - `auto_review`
      - `guardian_subagent`
    - Updates app-server README docs for the reviewer value.
    - Updates analytics and config requirements tests for the canonical
    auto_review value.
    
    
    ### Compatibility
    
    Existing configs and API payloads using:
    
    ```toml
    approvals_reviewer = "guardian_subagent"
    ```
    
    continue to load and map to the Auto-review reviewer behavior. 
    
    New serialization emits: 
    ```toml
    approvals_reviewer = "auto_review" 
    ```
    
    This PR intentionally does not rename the [features].guardian_approval
    key or broad internal Guardian symbols. Those are split out for a
    follow-up PR to keep this migration small and avoid touching large
    TUI/internal surfaces.
    
    **Verification**
    cargo test -p codex-protocol
    approvals_reviewer_serializes_auto_review_and_accepts_legacy_guardian_subagent
    cargo test -p codex-app-server-protocol
    approvals_reviewer_serializes_auto_review_and_accepts_legacy_guardian_subagent
  • app-server: accept permission profile overrides (#18279)
    ## Why
    
    `PermissionProfile` is becoming the canonical permissions shape shared
    by core and app-server. After app-server responses expose the active
    profile, clients need to be able to send that same shape back when
    starting, resuming, forking, or overriding a turn instead of translating
    through the legacy `sandbox`/`sandboxPolicy` shorthands.
    
    This still needs to preserve the existing requirements/platform
    enforcement model. A profile-shaped request can be downgraded or
    rejected by constraints, but the server should keep the user's
    elevated-access intent for project trust decisions. Turn-level profile
    overrides also need to retain existing read protections, including
    deny-read entries and bounded glob-scan metadata, so a permission
    override cannot accidentally drop configured protections such as
    `**/*.env = deny`.
    
    ## What changed
    
    - Adds optional `permissionProfile` request fields to `thread/start`,
    `thread/resume`, `thread/fork`, and `turn/start`.
    - Rejects ambiguous requests that specify both `permissionProfile` and
    the legacy `sandbox`/`sandboxPolicy` fields, including running-thread
    resume requests.
    - Converts profile-shaped overrides into core runtime filesystem/network
    permissions while continuing to derive the constrained legacy sandbox
    projection used by existing execution paths.
    - Preserves project-trust intent for profile overrides that are
    equivalent to workspace-write or full-access sandbox requests.
    - Preserves existing deny-read entries and `globScanMaxDepth` when
    applying turn-level `permissionProfile` overrides.
    - Updates app-server docs plus generated JSON/TypeScript schema fixtures
    and regression coverage.
    
    ## Verification
    
    - `cargo test -p codex-app-server-protocol schema_fixtures`
    - `cargo test -p codex-core
    session_configuration_apply_permission_profile_preserves_existing_deny_read_entries`
    
    
    
    
    
    
    
    ---
    [//]: # (BEGIN SAPLING FOOTER)
    Stack created with [Sapling](https://sapling-scm.com). Best reviewed
    with [ReviewStack](https://reviewstack.dev/openai/codex/pull/18279).
    * #18288
    * #18287
    * #18286
    * #18285
    * #18284
    * #18283
    * #18282
    * #18281
    * #18280
    * __->__ #18279
  • [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>
  • Support clear SessionStart source (#17073)
    ## Motivation
    
    The `SessionStart` hook already receives `startup` and `resume` sources,
    but sessions created from `/clear` previously looked like normal startup
    sessions. This makes it impossible for hook authors to distinguish
    between these with the matcher.
    
    ## Summary
    
    - Add `InitialHistory::Cleared` so `/clear`-created sessions can be
    distinguished from ordinary startup sessions.
    - Add `SessionStartSource::Clear` and wire it through core, app-server
    thread start params, and TUI clear-session flow.
    - Update app-server protocol schemas, generated TypeScript, docs, and
    related tests.
    
    
    https://github.com/user-attachments/assets/9cae3cb4-41c7-4d06-b34f-966252442e5c
  • dynamic tool calls: add param exposeToContext to optionally hide tool (#14501)
    This extends dynamic_tool_calls to allow us to hide a tool from the
    model context but still use it as part of the general tool calling
    runtime (for ex from js_repl/code_mode)
  • Add Smart Approvals guardian review across core, app-server, and TUI (#13860)
    ## Summary
    - add `approvals_reviewer = "user" | "guardian_subagent"` as the runtime
    control for who reviews approval requests
    - route Smart Approvals guardian review through core for command
    execution, file changes, managed-network approvals, MCP approvals, and
    delegated/subagent approval flows
    - expose guardian review in app-server with temporary unstable
    `item/autoApprovalReview/{started,completed}` notifications carrying
    `targetItemId`, `review`, and `action`
    - update the TUI so Smart Approvals can be enabled from `/experimental`,
    aligned with the matching `/approvals` mode, and surfaced clearly while
    reviews are pending or resolved
    
    ## Runtime model
    This PR does not introduce a new `approval_policy`.
    
    Instead:
    - `approval_policy` still controls when approval is needed
    - `approvals_reviewer` controls who reviewable approval requests are
    routed to:
      - `user`
      - `guardian_subagent`
    
    `guardian_subagent` is a carefully prompted reviewer subagent that
    gathers relevant context and applies a risk-based decision framework
    before approving or denying the request.
    
    The `smart_approvals` feature flag is a rollout/UI gate. Core runtime
    behavior keys off `approvals_reviewer`.
    
    When Smart Approvals is enabled from the TUI, it also switches the
    current `/approvals` settings to the matching Smart Approvals mode so
    users immediately see guardian review in the active thread:
    - `approval_policy = on-request`
    - `approvals_reviewer = guardian_subagent`
    - `sandbox_mode = workspace-write`
    
    Users can still change `/approvals` afterward.
    
    Config-load behavior stays intentionally narrow:
    - plain `smart_approvals = true` in `config.toml` remains just the
    rollout/UI gate and does not auto-set `approvals_reviewer`
    - the deprecated `guardian_approval = true` alias migration does
    backfill `approvals_reviewer = "guardian_subagent"` in the same scope
    when that reviewer is not already configured there, so old configs
    preserve their original guardian-enabled behavior
    
    ARC remains a separate safety check. For MCP tool approvals, ARC
    escalations now flow into the configured reviewer instead of always
    bypassing guardian and forcing manual review.
    
    ## Config stability
    The runtime reviewer override is stable, but the config-backed
    app-server protocol shape is still settling.
    
    - `thread/start`, `thread/resume`, and `turn/start` keep stable
    `approvalsReviewer` overrides
    - the config-backed `approvals_reviewer` exposure returned via
    `config/read` (including profile-level config) is now marked
    `[UNSTABLE]` / experimental in the app-server protocol until we are more
    confident in that config surface
    
    ## App-server surface
    This PR intentionally keeps the guardian app-server shape narrow and
    temporary.
    
    It adds generic unstable lifecycle notifications:
    - `item/autoApprovalReview/started`
    - `item/autoApprovalReview/completed`
    
    with payloads of the form:
    - `{ threadId, turnId, targetItemId, review, action? }`
    
    `review` is currently:
    - `{ status, riskScore?, riskLevel?, rationale? }`
    - where `status` is one of `inProgress`, `approved`, `denied`, or
    `aborted`
    
    `action` carries the guardian action summary payload from core when
    available. This lets clients render temporary standalone pending-review
    UI, including parallel reviews, even when the underlying tool item has
    not been emitted yet.
    
    These notifications are explicitly documented as `[UNSTABLE]` and
    expected to change soon.
    
    This PR does **not** persist guardian review state onto `thread/read`
    tool items. The intended follow-up is to attach guardian review state to
    the reviewed tool item lifecycle instead, which would improve
    consistency with manual approvals and allow thread history / reconnect
    flows to replay guardian review state directly.
    
    ## TUI behavior
    - `/experimental` exposes the rollout gate as `Smart Approvals`
    - enabling it in the TUI enables the feature and switches the current
    session to the matching Smart Approvals `/approvals` mode
    - disabling it in the TUI clears the persisted `approvals_reviewer`
    override when appropriate and returns the session to default manual
    review when the effective reviewer changes
    - `/approvals` still exposes the reviewer choice directly
    - the TUI renders:
    - pending guardian review state in the live status footer, including
    parallel review aggregation
      - resolved approval/denial state in history
    
    ## Scope notes
    This PR includes the supporting core/runtime work needed to make Smart
    Approvals usable end-to-end:
    - shell / unified-exec / apply_patch / managed-network / MCP guardian
    review
    - delegated/subagent approval routing into guardian review
    - guardian review risk metadata and action summaries for app-server/TUI
    - config/profile/TUI handling for `smart_approvals`, `guardian_approval`
    alias migration, and `approvals_reviewer`
    - a small internal cleanup of delegated approval forwarding to dedupe
    fallback paths and simplify guardian-vs-parent approval waiting (no
    intended behavior change)
    
    Out of scope for this PR:
    - redesigning the existing manual approval protocol shapes
    - persisting guardian review state onto app-server `ThreadItem`s
    - delegated MCP elicitation auto-review (the current delegated MCP
    guardian shim only covers the legacy `RequestUserInput` path)
    
    ---------
    
    Co-authored-by: Codex <noreply@openai.com>
  • chore: add a separate reject-policy flag for skill approvals (#14271)
    ## Summary
    - add `skill_approval` to `RejectConfig` and the app-server v2
    `AskForApproval::Reject` payload so skill-script prompts can be
    configured independently from sandbox and rule-based prompts
    - update Unix shell escalation to reject prompts based on the actual
    decision source, keeping prefix rules tied to `rules`, unmatched command
    fallbacks tied to `sandbox_approval`, and skill scripts tied to
    `skill_approval`
    - regenerate the affected protocol/config schemas and expand
    unit/integration coverage for the new flag and skill approval behavior
  • fix(core) default RejectConfig.request_permissions (#14165)
    ## Summary
    Adds a default here so existing config deserializes
    
    ## Testing
    - [x] Added a unit test
  • feat(approvals) RejectConfig for request_permissions (#14118)
    ## Summary
    We need to support allowing request_permissions calls when using
    `Reject` policy
    
    <img width="1133" height="588" alt="Screenshot 2026-03-09 at 12 06
    40 PM"
    src="https://github.com/user-attachments/assets/a8df987f-c225-4866-b8ab-5590960daec5"
    />
    
    Note that this is a backwards-incompatible change for Reject policy. I'm
    not sure if we need to add a default based on our current use/setup
    
    ## Testing
    - [x] Added tests
    - [x] Tested locally
  • app-server service tier plumbing (plus some cleanup) (#13334)
    followup to https://github.com/openai/codex/pull/13212 to expose fast
    tier controls to app server
    (majority of this PR is generated schema jsons - actual code is +69 /
    -35 and +24 tests )
    
    - add service tier fields to the app-server protocol surfaces used by
    thread lifecycle, turn start, config, and session configured events
    - thread service tier through the app-server message processor and core
    thread config snapshots
    - allow runtime config overrides to carry service tier for app-server
    callers
    
    cleanup:
    - Removing useless "legacy" code supporting "standard" - we moved to
    None | "fast", so "standard" is not needed.
  • feat: add service name to app-server (#12319)
    Add service name to the app-server so that the app can use it's own
    service name
    
    This is on thread level because later we might plan the app-server to
    become a singleton on the computer
  • feat: add Reject approval policy with granular prompt rejection controls (#12087)
    ## Why
    
    We need a way to auto-reject specific approval prompt categories without
    switching all approvals off.
    
    The goal is to let users independently control:
    - sandbox escalation approvals,
    - execpolicy `prompt` rule approvals,
    - MCP elicitation prompts.
    
    ## What changed
    
    - Added a new primary approval mode in `protocol/src/protocol.rs`:
    
    ```rust
    pub enum AskForApproval {
        // ...
        Reject(RejectConfig),
        // ...
    }
    
    pub struct RejectConfig {
        pub sandbox_approval: bool,
        pub rules: bool,
        pub mcp_elicitations: bool,
    }
    ```
    
    - Wired `RejectConfig` semantics through approval paths in `core`:
      - `core/src/exec_policy.rs`
        - rejects rule-driven prompts when `rules = true`
        - rejects sandbox/escalation prompts when `sandbox_approval = true`
    - preserves rule priority when both rule and sandbox prompt conditions
    are present
      - `core/src/tools/sandboxing.rs`
    - applies `sandbox_approval` to default exec approval decisions and
    sandbox-failure retry gating
      - `core/src/safety.rs`
    - keeps `Reject { all false }` behavior aligned with `OnRequest` for
    patch safety
        - rejects out-of-root patch approvals when `sandbox_approval = true`
      - `core/src/mcp_connection_manager.rs`
        - auto-declines MCP elicitations when `mcp_elicitations = true`
    
    - Ensured approval policy used by MCP elicitation flow stays in sync
    with constrained session policy updates.
    
    - Updated app-server v2 conversions and generated schema/TypeScript
    artifacts for the new `Reject` shape.
    
    ## Verification
    
    Added focused unit coverage for the new behavior in:
    - `core/src/exec_policy.rs`
    - `core/src/tools/sandboxing.rs`
    - `core/src/mcp_connection_manager.rs`
    - `core/src/safety.rs`
    - `core/src/tools/runtimes/apply_patch.rs`
    
    Key cases covered include rule-vs-sandbox prompt precedence, MCP
    auto-decline behavior, and patch/sandbox retry behavior under
    `RejectConfig`.
  • chore(app-server): add experimental annotation to relevant fields (#10928)
    These fields had always been documented as experimental/unstable with
    docstrings, but now let's actually use the `experimental` annotation to
    be more explicit.
    
    - thread/start.experimentalRawEvents
    - thread/resume.history
    - thread/resume.path
    - thread/fork.path
    - turn/start.collaborationMode
    - account/login/start.chatgptAuthTokens
  • add none personality option (#10688)
    - add none personality enum value and empty placeholder behavior\n- add
    docs/schema updates and e2e coverage
  • feat: experimental flags (#10231)
    ## Problem being solved
    - We need a single, reliable way to mark app-server API surface as
    experimental so that:
      1. the runtime can reject experimental usage unless the client opts in
    2. generated TS/JSON schemas can exclude experimental methods/fields for
    stable clients.
    
    Right now that’s easy to drift or miss when done ad-hoc.
    
    ## How to declare experimental methods and fields
    - **Experimental method**: add `#[experimental("method/name")]` to the
    `ClientRequest` variant in `client_request_definitions!`.
    - **Experimental field**: on the params struct, derive `ExperimentalApi`
    and annotate the field with `#[experimental("method/name.field")]` + set
    `inspect_params: true` for the method variant so
    `ClientRequest::experimental_reason()` inspects params for experimental
    fields.
    
    ## How the macro solves it
    - The new derive macro lives in
    `codex-rs/codex-experimental-api-macros/src/lib.rs` and is used via
    `#[derive(ExperimentalApi)]` plus `#[experimental("reason")]`
    attributes.
    - **Structs**:
    - Generates `ExperimentalApi::experimental_reason(&self)` that checks
    only annotated fields.
      - The “presence” check is type-aware:
        - `Option<T>`: `is_some_and(...)` recursively checks inner.
        - `Vec`/`HashMap`/`BTreeMap`: must be non-empty.
        - `bool`: must be `true`.
        - Other types: considered present (returns `true`).
    - Registers each experimental field in an `inventory` with `(type_name,
    serialized field name, reason)` and exposes `EXPERIMENTAL_FIELDS` for
    that type. Field names are converted from `snake_case` to `camelCase`
    for schema/TS filtering.
    - **Enums**:
    - Generates an exhaustive `match` returning `Some(reason)` for annotated
    variants and `None` otherwise (no wildcard arm).
    - **Wiring**:
    - Runtime gating uses `ExperimentalApi::experimental_reason()` in
    `codex-rs/app-server/src/message_processor.rs` to reject requests unless
    `InitializeParams.capabilities.experimental_api == true`.
    - Schema/TS export filters use the inventory list and
    `EXPERIMENTAL_CLIENT_METHODS` from `client_request_definitions!` to
    strip experimental methods/fields when `experimental_api` is false.
  • feat: vendor app-server protocol schema fixtures (#10371)
    Similar to what @sayan-oai did in openai/codex#8956 for
    `config.schema.json`, this PR updates the repo so that it includes the
    output of `codex app-server generate-json-schema` and `codex app-server
    generate-ts` and adds a test to verify it is in sync with the current
    code.
    
    Motivation:
    - This makes any schema changes introduced by a PR transparent during
    code review.
    - In particular, this should help us catch PRs that would introduce a
    non-backwards-compatible change to the app schema (eventually, this
    should also be enforced by tooling).
    - Once https://github.com/openai/codex/pull/10231 is in to formalize the
    notion of "experimental" fields, we can work on ensuring the
    non-experimental bits are backwards-compatible.
    
    `codex-rs/app-server-protocol/tests/schema_fixtures.rs` was added as the
    test and `just write-app-server-schema` can be use to generate the
    vendored schema files.
    
    Incidentally, when I run:
    
    ```
    rg _ codex-rs/app-server-protocol/schema/typescript/v2
    ```
    
    I see a number of `snake_case` names that should be `camelCase`.