## Why
Code-mode tool results could return to the model while an MCP
elicitation was still waiting for user input. This differed from
parallel tool calling and could let the model continue before the user
resolved the request.
We need one session-level view of outstanding elicitations so tool
runtimes can consistently hold results until every pending elicitation
is resolved.
## What changed
- Added a counted, session-owned ElicitationService with RAII
registrations.
- Registered both core-originated and server-originated MCP elicitations
with the service.
- Migrated out-of-band elicitation tracking and unified exec timeout
pausing to the shared service.
- Made code-mode functions.exec and functions.wait capture their runtime
result normally, then hold it before returning while an elicitation is
outstanding.
- Kept terminate: true immediate; only its result is held.
- Preserved model-visible wall time across the elicitation hold.
- Kept the behavior session-scoped, with concurrent elicitations holding
the pause until all registrations are released.
## 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.
## Why
Selected plugin metadata is stable, but MCP processes are live runtime
state. They need different lifetimes:
- the MCP extension caches manifest, MCP, and connector declarations for
each stable selected root;
- each model step projects that cached metadata through the roots that
resolved as ready for that exact step;
- the MCP manager is rebuilt only when that availability projection
changes.
This matches executor skills: both features consume the same resolved
step roots instead of inferring readiness from the turn's selected
environments.
## Behavior
```text
E1 not ready for this step
-> no E1 MCP servers or connectors
-> cached plugin metadata stays in ext/mcp
E1 becomes ready
-> reuse cached metadata
-> publish one MCP runtime containing E1 capabilities
same ready roots on the next step
-> reuse the exact runtime; no rediscovery and no MCP restart
resume
-> create new extension thread state and a new MCP runtime
```
All model-facing consumers use the same step snapshot:
```text
resolved selected roots
|
v
extension MCP/connector projection
|
v
{ MCP config, connector snapshot, MCP manager }
|
+-> advertise model tools
+-> build app/connector tools
+-> execute MCP calls
```
## Cache contract
The existing MCP extension owns a cache keyed by the full
`SelectedCapabilityRoot`:
```rust
let state = thread_store.get_or_init(SelectedExecutorPluginMcpState::default);
```
The cache lives with extension thread state. Environment availability
filters projection but does not invalidate metadata. Resume creates new
thread state. There is no file watcher or executor generation because
contents behind a stable environment/root are assumed stable.
## What changes
- Keeps executor plugin discovery and cached metadata in `ext/mcp`.
- Caches MCP and connector declarations together per selected root.
- Uses the step's already-resolved capability roots, including lazy
environments that are not turn environments.
- Reuses the current MCP runtime when the ready-root projection is
unchanged.
- Uses the same step MCP manager and connector snapshot for
model-visible tools and execution.
- Resolves direct thread-scoped MCP requests from the current
selected-root projection.
## Deliberately out of scope
- `app/list` remains based on the latest global host-plugin state; this
PR does not make its response or notifications thread-specific.
- `required = true` startup semantics do not apply to delayed executor
MCP activation.
- No filesystem/content invalidation.
- No transport-disconnect watcher.
- No executor generations or environment replacement semantics.
- No client sharing across complete manager replacements.
## Stack
1. Extension-owned World State sections.
2. Project executor skills through World State.
3. Pin one MCP runtime to each model step.
4. **This PR:** project selected MCP and connector state from
extension-owned metadata.
5. Integration coverage for selected capability availability and resume.
## Verification
-
`selected_plugin_servers_use_managed_requirements_for_the_selected_root_id`
- The stacked integration PR covers unavailable to ready activation,
unchanged-runtime reuse, skills, MCP tools, connector attribution, and
cold resume.
## Why
An MCP refresh can replace the session's current manager while a model
step is still running. The step must execute calls through the same
manager whose tools it advertised.
## Boundary
```text
current session MCP runtime
|
| capture once for this model step
v
StepContext.mcp
- exact MCP config
- exact connection manager
- exact runtime environment context
```
```rust
pub struct McpRuntimeSnapshot {
config: Arc<McpConfig>,
manager: Arc<McpConnectionManager>,
runtime_context: McpRuntimeContext,
}
```
## Example
```text
step A captures runtime A and advertises A's tools
refresh publishes runtime B
step A tool call -> runtime A
next step -> runtime B
```
Capturing the snapshot is only an `Arc` clone. It does not restart MCPs
or make an RPC.
## What changes
- Captures one MCP runtime in `StepContext`.
- Uses it for tool planning, tool calls, resources, approvals, connector
attribution, and elicitation.
- Publishes replacement runtimes atomically.
- Lets an old runtime live only while an in-flight step or request still
holds its `Arc`.
Most of this diff is mechanical routing from the session-global manager
to `step_context.mcp`; it does not introduce selected-plugin discovery
yet.
## What does not change
- No plugin or extension migration.
- No new MCP cache policy.
- No environment file watching.
- No client sharing between separate managers.
## Stack
1. Extension-owned World State sections.
2. Project executor skills through World State.
3. **This PR:** pin one MCP runtime to each model step.
4. Project selected MCP/app/connector metadata by environment
availability.
5. One end-to-end integration scenario.
## Why
With deferred executors, a turn can begin before a remote environment
attaches. AGENTS.md discovery previously ran only during session setup,
so instructions from a later environment never reached the model or the
session instruction sources.
WorldState persistence has now landed, so this uses the durable
model-visible baseline directly instead of carrying a temporary
resume/fork compatibility path.
## What
- Add an `AgentsMdManager` in `SessionServices` to own host
instructions, loaded state, and refresh caching.
- When `DeferredExecutor` is enabled, refresh AGENTS.md when attached
environment selections change and freeze the result in the corresponding
`StepContext`.
- Represent AGENTS.md as a persisted WorldState section for every
session, with bounded initial, replacement, and removal updates.
- Remove duplicate AGENTS.md state and rendering from
`SessionConfiguration` and `TurnContext`.
- Build initial context, per-request updates, and compaction context
from the same step-scoped value.
- On resume and fork, compare current instructions with the restored
WorldState baseline and inject a replacement exactly once when they
differ.
Builds on #29833, #29835, and #29837.
## Tests
- Covers a remote environment becoming ready mid-turn, with AGENTS.md
appearing on the next request exactly once and updating canonical
instruction sources.
- Covers full, unchanged, replaced, and removed AGENTS.md WorldState
rendering.
- Covers changed instructions across cold resume and fork without
duplicate reinjection.
- Covers remote-v2 compaction retaining creation-time instructions in
the live session and cold resume appending one replacement when the
source changed.
- Ran focused `codex-core` AGENTS.md, WorldState, and context-update
test suites.
## Why
Ultra should be one user-facing reasoning selection for work that
benefits from both maximum reasoning and proactive multi-agent
delegation. Without it, clients must coordinate maximum reasoning with
the experimental `multiAgentMode` setting, even though the inference
backend still expects its existing `max` effort value.
This change makes reasoning effort the source of truth: clients select
`ultra`, core derives proactive multi-agent behavior when the turn is
eligible for multi-agent V2, and inference requests continue to use the
backend-compatible `max` value.
## What changed
- Add `ultra` as a first-class reasoning effort and preserve
model-catalog ordering when exposing it to clients.
- Convert `ultra` to `max` at the inference request boundary, including
Responses HTTP/WebSocket requests, startup prewarm, compaction, and
memory summarization.
- Derive effective multi-agent mode per turn from effective reasoning
effort:
- eligible multi-agent V2 + `ultra` → `proactive`
- eligible multi-agent V2 + any other effort → `explicitRequestOnly`
- V1 or otherwise ineligible sessions → no multi-agent mode instruction
- Keep the derived effective mode in turn context history so successive
turns can emit a developer-message update only when the effective mode
changes.
- Remove selected multi-agent mode from core session configuration, turn
construction, thread settings, resume/fork restoration, and subagent
spawn plumbing. Subagents inherit reasoning effort and derive their own
effective mode.
- Retain the experimental app-server `multiAgentMode` fields for wire
compatibility while marking them deprecated. Request values are accepted
but ignored; compatibility response fields report `explicitRequestOnly`.
- Display Ultra in the TUI using the order supplied by `model/list`.
## Validation
- `just test -p codex-core ultra_reasoning_uses_max_for_requests`
- `just test -p codex-tui model_reasoning_selection_popup`
## Why
Work(TPP) threads can be launched from the Desktop app, but if they all
keep the Desktop app's default originator then downstream attribution
cannot distinguish local Work launches from cloud-backed Work launches.
`thread/start.serviceName` already carries that launch signal, while
`SessionMeta.originator` is the durable thread-level value that survives
resume and fork.
This change converts the Desktop Work service names into an effective
originator at thread creation time, persists that originator with the
thread, and keeps using it for later model requests and memory writes.
## What changed
- Map `CODEX_WORK_LOCAL` and `CODEX_WORK_CLOUD` service names to
per-thread originators, while preserving
`CODEX_INTERNAL_ORIGINATOR_OVERRIDE` as the highest-precedence override.
- Persist the effective originator in `SessionMeta.originator`, read it
back on resume/fork, and inherit the parent originator for subagent
spawns when there is no persisted session metadata.
- Handle truncated `SpawnAgentForkMode::LastNTurns` forks by falling
back to the live parent originator when the forked history no longer
includes `SessionMeta`.
- Thread the per-thread originator through Responses headers,
websocket/compaction request paths, thread-store creation, rollout
metadata, and memory stage-one telemetry.
## Verification
- `just test -p codex-core
agent::control::tests::spawn_thread_subagent_inherits_parent_originator_without_fork
agent::control::tests::spawn_thread_subagent_fork_last_n_turns_inherits_parent_originator_without_session_meta
thread_manager::tests::originator_override_precedes_service_name_remapping`
- `just test -p codex-core
agent::control::tests::resume_thread_subagent_restores_stored_metadata_and_effective_multi_agent_mode`
- `just test -p codex-memories-write`
- `just fix -p codex-core -p codex-memories-write`
- `git diff --check`
## Description
This PR cuts Codex over from generic `ResponseItem.metadata` (introduced
here: https://github.com/openai/codex/pull/28355) to
`ResponseItem.internal_chat_message_metadata_passthrough`, which is the
blessed path and has strongly-typed keys.
For now we have to drop this MAv2 usage of `metadata`:
https://github.com/openai/codex/pull/28561 until we figure out where
that should live.
## 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`
## Why
Multi-agent v2 currently carries an explicit-request-only delegation
rule in its static usage hint. That provides a safe default, but it
prevents clients from selecting proactive delegation per turn without
changing static guidance or rewriting prior model context.
This change makes delegation mode a session selection that can be
updated through `turn/start`, while deriving the effective model-visible
mode separately for each turn. Eligible multi-agent v2 turns remain
explicit-request-only unless proactive mode is both selected and
enabled.
## What changed
- Add the experimental `turn/start.multiAgentMode` parameter with
`explicitRequestOnly` and `proactive` values. Omission retains the
loaded session's current optional selection.
- Add the default-off `features.multi_agent_mode` feature gate. Eligible
multi-agent v2 turns use the selected mode when enabled; an unset
selection or disabled gate resolves to `explicitRequestOnly`.
- Treat mode prompting as inapplicable for multi-agent v1 and other
unsupported session configurations, producing no multi-agent mode
developer message rather than rejecting the turn.
- Move the explicit-request-only rule out of the static v2 usage hint
and into a bounded, tagged developer context fragment.
- Emit the effective mode in initial context and only when that
effective mode changes on later turns.
- Persist the effective mode in `TurnContextItem` as the durable
baseline for resume and context-update comparisons.
Historical rollout items are not rewritten. Later mode developer
messages establish the current rule incrementally.
## Not covered
- Initial selection through `thread/start` and selected-mode reporting
from thread lifecycle/settings APIs; those are isolated in the stacked
#28792.
- A TUI control or slash command for selecting the mode.
- Persisting a preferred mode to `config.toml`; selection remains
session/turn scoped.
- Changes to multi-agent concurrency limits, tool availability, or model
catalog capability declarations.
- Rewriting historical rollout prompt items. Cold resume restores the
latest persisted effective mode when available while leaving historical
developer messages intact.
## Verification
- `CARGO_INCREMENTAL=0 just test -p codex-core multi_agent_mode`
- Focused app-server coverage verifies that `turn/start.multiAgentMode`
produces proactive developer instructions for an eligible v2 turn.
## Stack
Followed by #28792, which adds `thread/start` initialization and
lifecycle/settings observability.
## Why
Make it possible to load AGENTS.md from remote exec-servers whose OS is
different than app-server.
## What
- keep `AGENTS.md` discovery and provenance as `PathUri`, with
root-aware parent and ancestor traversal
- expose lifecycle instruction sources as legacy app-server path strings
in events while retaining `PathUri` internally
- preserve and test mixed POSIX and Windows paths in model context and
TUI status output
- cover remote Windows loading end to end by seeding the Wine prefix
through host filesystem APIs
- fix bug in `PathUri`'s parent() implementation that would erase
Windows drive letters
Fixes#28263.
## Why
When a thread starts with `/goal`, the goal extension can update SQLite
goal state before the thread has any user-turn rollout items.
`thread/list` and `thread/search` rely on persisted listing metadata, so
a goal-first live thread could be absent from app-server listings after
restart even though the goal itself existed.
This regressed when goal handling moved out of core: the core path wrote
the goal update through the live thread rollout path, while the
extension-backed app-server path only updated goal state and emitted the
live notification.
## What
- Add `GoalSetOutcome::thread_goal_updated_item()` so the goal extension
owns the canonical `ThreadGoalUpdated` rollout item shape.
- Expose a narrow `CodexThread::append_rollout_items()` helper that
appends through the live thread and keeps derived SQLite metadata in
sync.
- When app-server sets a goal on an active live thread, persist the goal
update through that live-thread path.
- Add an app-server regression test that starts a live thread with
`thread/goal/set` and verifies it appears in state-DB-only
`thread/list`.
## Verification
- `env -u CODEX_SQLITE_HOME just test -p codex-app-server
goal_first_live_thread_appears_in_state_db_thread_list`
## Why
It should be possible for app-server to handle "foreign" OS paths in
unified_exec working directories, allowing e.g. a Linux app-server to
run processes on e.g. a Windows exec-server.
## What
Convert the core unified_exec cwd values to use `PathUri`.
Adds fallible path conversion in several places to try to minimize the
scope of this change. The only time this change suppresses errors from
converting `PathUri` to an `AbsolutePathBuf` is when the turn is
configured with no sandboxing at all to allow us to make progress
testing without sandboxing.
Future changes to apply_patch and sandboxing will clean up these error
paths.
A tool's cwd is resolved from joining a model-provided workdir to the
environment's cwd. When using `AbsolutePathBuf::join()`, an
absolute-path workdir would overwrite the environment's cwd and we would
resolve permissions/sandboxing against the model-provided path. This
change extends `PathUri::join()` to also treat an absolute rhs as an
override of the base/lhs.
This also removes some coverage from the remove_env_windows tests until
a follow-up converts foreign paths in command exec events correctly.
## Breaking Changes
When using `AbsolutePathBuf::join()` for workdir resolution, we ended up
resolving tilde-prefixed paths against the app-server's `$HOME`, e.g.
`~/foo/bar` becomes `/home/anp/foo/bar`. It's difficult to do this with
`PathUri` joining, so after offline discussion this PR no longer
implements it.
A quick check of some power users' rollouts suggests that models don't
actually generate home-prefixed absolute working directories for their
spawns, so this shouldn't have any real blast radius.
## Why
#28152 jumped the gun on moving the rollout format to store URIs, and
would likely break compat with some features that don't go through the
same types as the core logic.
## What
Make `TurnContextItem.cwd` an `AbsolutePathBuf` again, remove test added
for `PathUri` serialization in rollouts. Also drops a bunch of error
paths that are no longer needed.
## Why
Model-visible `<environment_context>` should match the environment of
the executor, not of the app server.
Stacked on #28146.
## What
- Keep selected environment cwd values as `PathUri` while building
environment context.
- Render cwd text using the path convention represented by the URI, with
the canonical URI as a fallback.
- Preserve compatibility with legacy `TurnContextItem.cwd` values when
reconstructing and diffing context.
- Extend the Wine-backed remote Windows test to assert that the model
sees `powershell` and `C:\windows`.
## Description
This PR adds an optional `metadata` field to `ResponseItem` for
Responses API calls. Only mechanical plumbing, no actual values
populated and sent yet. Turns out just adding a new field to
`ResponseItem` has quite a large blast radius already.
This change is backwards compatible because `metadata` is optional and
omitted when absent, so existing response items and rollout history
without it still deserialize and requests that do not set it keep the
same wire shape. For provider compatibility, we strip out `metadata`
before non-OpenAI Responses requests so Azure and AWS Bedrock never see
this field.
My followup PR here will actually make use of it to start storing and
passing along `turn_id`: https://github.com/openai/codex/pull/28360
## What changed
- Added `ResponseItemMetadata` with optional `turn_id`, plus optional
`metadata` on Responses API item variants and inter-agent communication.
- Preserved item metadata through response-item rewrites such as
truncation, missing tool-output synthesis, compaction history
rebuilding, visible-history conversion, rollout/resume, and generated
app-server schemas/types.
- Strip item metadata from non-OpenAI Responses requests while
preserving it for OpenAI-shaped requests.
- Updated the mechanical fixture/test construction churn required by the
new optional field.
## Why
`selectedCapabilityRoots` belongs to one thread, but MCP contributors
previously received only the global Codex config. That left no clean way
for a selected executor capability to contribute MCP servers to its own
thread.
## What this PR does
- Gives MCP contributors a small context containing the config and, for
a running thread, its frozen host-seeded inputs.
- Uses the same thread inputs during startup, status queries, refreshes,
and skill dependency checks.
- Keeps threadless MCP operations and the existing hosted Apps behavior
unchanged.
- Adds coverage showing that two threads resolve independent
registrations and that later lifecycle mutations do not change the
frozen MCP inputs.
This PR does not discover plugin manifests, add MCP servers, or launch
anything new. It only establishes the thread-scoped registration
boundary.
## Follow-ups
- Resolve selected executor plugin roots through their owning
environment filesystem.
- Convert their stdio MCP declarations into environment-bound
registrations and add an executor MCP end-to-end test.
## Verification
- `just fmt`
- `cargo check --tests -p codex-protocol -p codex-extension-api -p
codex-mcp-extension -p codex-core -p codex-app-server`
Tests and Clippy were not run.
## Summary
Codex Apps needs app-server as the source of truth for chat-started
background terminals instead of guessing from local process trees.
This PR adds experimental v2 APIs to list and terminate background
terminals for a loaded thread using app-server process ids, so clients
can manage background terminals without local PID discovery.
## Changes
- `thread/backgroundTerminals/list` returns paginated background
terminal records with `itemId`, app-server `processId`, `command`,
`cwd`, nullable `osPid`, nullable `cpuPercent`, and nullable `rssKb`.
- `thread/backgroundTerminals/terminate` terminates one running
background terminal by app-server `processId` and returns whether a
process was terminated.
- Background terminal list and terminate operations use unified-exec
process manager state as their source of truth.
## 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.
## Why
Multi-Agent V2 concurrency should count active non-root turns, not
resident or durable agent threads. The limit is intentionally best
effort: admission checks are synchronous, but concurrent successful
checks may overshoot slightly.
## What changed
- Keep one root-derived execution limit on the shared `AgentControl`.
- Count active V2 subagent turns with an RAII guard owned by
`RunningTask`.
- Check capacity before spawning or starting an idle agent, including
direct app-server `turn/start` submissions.
- Preserve queued delivery for agents that are already running.
- Exempt automatic idle continuations so `/goal` work is not dropped
when capacity is temporarily full.
- Keep root and V1 turns outside this limiter.
## Test coverage
- `execution_guards_count_active_v2_subagent_turns`
- `execution_guards_ignore_root_and_v1_turns`
- `v2_nested_spawn_checks_shared_active_execution_capacity`
## Stack
1. [#26547](https://github.com/openai/codex/pull/26547) - [1 of 2] Align
goal extension with core behavior
2. [#26548](https://github.com/openai/codex/pull/26548) - [2 of 2] Move
goal runtime to extension
## Why
This PR completes the switch of the goal behavior to the
extension-backed runtime and removes the old core goal implementation.
## What Changed
- Installs the goal extension for app-server `ThreadManager` sessions.
- Routes app-server thread goal `get`, `set`, and `clear` through
`GoalService`.
- Uses thread-idle lifecycle emission after goal resume and snapshot
ordering so the extension can decide whether to continue the goal.
- Forwards extension goal updates through a FIFO async app-server
notification path so backpressure does not drop them or reorder updates.
- Keeps review turns from enabling goal runtime behavior.
- Plans extension tools before dynamic tools so built-in goal tool names
keep their old precedence when goals are enabled.
- Removes the old core goal runtime, core goal tool handlers, and core
goal tool specs.
- Updates tests that were coupled to the core-owned goal runtime while
leaving the legacy `<goal_context>` compatibility path in core for old
threads.
- Removes the stale cargo-shear ignore now that `codex-goal-extension`
is used by the workspace.
- Keeps realtime event matching exhaustive after removing the old
goal-specific realtime text path.
## Validation
- Ran manual `/goal` runs in TUI. Validated time accounting matched
wall-clock time and goal lifecycle state transitions.
## Why
Thread settings cwd overrides are expected to be resolved before they
enter core. Keeping this boundary as a plain `PathBuf` made it easy for
core/session code to keep fallback normalization and relative-path
resolution logic in places that should only receive an already-resolved
cwd.
This is intentionally the absolute-cwd-only slice: it does not change
environment selection stickiness or cwd-to-default-environment fallback
behavior.
## What changed
- Changes `ThreadSettingsOverrides.cwd`,
`CodexThreadSettingsOverrides.cwd`, and `SessionSettingsUpdate.cwd` to
use `AbsolutePathBuf`.
- Removes core-side cwd normalization/resolution from session settings
updates.
- Updates affected core/app-server test helpers and callsites to pass
existing absolute cwd values or use `abs()` helpers.
## Validation
Opening as draft so CI can start while local validation continues.
## Why
Workspace-specific `AGENTS.md` loading needs to use the selected
environment filesystem so remote workspaces and child agents read
instructions from their actual environment instead of the host
filesystem. The app-server should report the same instruction sources
the initialized thread actually loaded, rather than independently
rescanning configuration and filesystem state.
## What changed
- Introduce `LoadedAgentsMd` to retain ordered user, project, and
internal instructions with their provenance.
- Load and canonicalize workspace `AGENTS.md` paths through the primary
`EnvironmentManager` environment, then render the loaded instructions
when constructing turn context.
- Expose cached loaded instruction sources from initialized threads and
use them for app-server start, resume, and fork responses.
- Preserve global `CODEX_HOME` loading and separator behavior while
excluding empty project files that did not supply model-visible
instructions.
- Add integration coverage for CLI injection, selected-environment
provenance and rendering, empty environment selection, and cached
sources on loaded-thread resume.
## Validation
- `just test -p codex-core agents_md`
- `just test -p codex-core
selected_environment_sources_match_model_visible_instructions`
- `just test -p codex-exec agents_md`
- `just test -p codex-app-server instruction_sources`
- `just test -p codex-app-server --status-level fail`
## Why
- Thread initialization analytics do not identify the source thread for
forked threads.
- The session viewer needs this lineage to construct thread trees.
- Depends on openai/openai#987854. Do not release this change before
that backend schema change is deployed.
## What Changed
- Adds optional `forked_from_thread_id` to `codex_thread_initialized`.
- Populates it from the existing thread fork lineage for app-server and
in-process subagent initialization paths.
- Keeps it null for non-forked threads.
## Verification
- `just fmt`
- `just test -p codex-analytics`
- `just test -p codex-app-server
thread_fork_tracks_thread_initialized_analytics`
## Why
Goal idle continuation is extension-triggered model-visible work, so it
should follow one core-owned rule for when automatic work may start. In
particular, it should not jump ahead of queued user/client work, start
while another task is active, or inject a continuation turn while the
thread is in Plan mode.
Keeping this policy in `try_start_turn_if_idle` avoids passing
`collaboration_mode` or review-specific state through
`ThreadLifecycleContributor::on_thread_idle`. Active `/review` is
covered by the same active-task gate because Review turns are not
steerable.
## What Changed
- Teach `Session::try_start_turn_if_idle` to reject automatic idle turns
in Plan mode, both before reserving an idle turn and after building the
turn context.
- Document `CodexThread::try_start_turn_if_idle` as the extension-facing
gate for automatic idle work, including Plan-mode and active Review-task
behavior.
- Add focused coverage for Plan-mode rejection and active Review-task
rejection without queuing synthetic input.
## Testing
- `just test -p codex-core try_start_turn_if_idle`
## Why
#25450 attempts a broad `SandboxPolicy` removal across several unrelated
surfaces, which makes it hard to review and still leaves new helper code
moving legacy policies around. This PR is a narrower alternative:
migrate only the exec-side Windows sandbox plumbing so the review can
focus on one production path and one compatibility boundary.
The goal is to stop threading `SandboxPolicy` through exec code without
expanding the migration into app-server, protocol, telemetry, config, or
session behavior.
## What changed
- Removed `ExecRequest::compatibility_sandbox_policy()`.
- Changed the Windows restricted-token and elevated filesystem override
helpers to accept `PermissionProfile` plus the split filesystem/network
policies instead of a `SandboxPolicy`.
- Kept the remaining legacy projection local to the writable-root
comparison that still needs to compare split policy behavior against the
legacy Windows backend model.
- Rejected restricted split filesystem policies that still grant
full-disk writes before using the Windows restricted-token backend,
preserving the previous clear-failure behavior for profiles that project
to `ExternalSandbox`.
- Updated the Windows sandbox override tests to exercise the new call
shape and cover the full-write split-profile regression.
## Verification
- `just test -p codex-core windows_restricted_token`
- `just test -p codex-core windows_elevated`
Stack split from #25708. Original PR intentionally left open. This third
PR resolves the effective per-thread multi-agent runtime from persisted
metadata, inherited runtime, and current model selection.
## Why
The goal extension needs a way to resume an active goal after the thread
becomes idle, but the old core goal runtime should not be refactored as
part of this step. The missing piece is a small core-owned turn-start
primitive: let an extension ask for a normal model turn only when the
thread is idle, and otherwise fail without injecting into whatever is
currently active.
## What Changed
- Adds `CodexThread::try_start_turn_if_idle(...)` as the narrow
extension-facing primitive for synthetic idle work.
- Implements the session side so it refuses to start when:
- the provided input is empty,
- the session is in plan mode,
- a turn is already active, or
- trigger-turn mailbox work is pending.
- Gives trigger-turn mailbox work priority if it appears while the idle
turn is being prepared.
- Wires `GoalExtension::on_thread_idle` to read the active persisted
goal and submit the continuation prompt through this idle-only
primitive.
- Keeps the legacy core goal continuation implementation in place
instead of folding it into this PR.
## Behavior
This is intentionally best-effort. If `try_start_turn_if_idle` observes
that the thread is not idle, or that higher-priority mailbox work should
run first, it returns the input to the caller. The goal extension drops
that continuation prompt and waits for a future idle opportunity instead
of injecting stale synthetic goal text into an active turn.
## Validation
- `just test -p codex-core
try_start_turn_if_idle_rejects_active_turn_without_injecting`
- `just test -p codex-goal-extension`
## Why
This PR
https://github.com/openai/codex/pull/24161#discussion_r3325692763
revealed a subagent data modeling issue, where we overloaded
`forked_from_id` to also mean `parent_thread_id`. That's incorrect since
guardian and review subagents can be a subagent and NOT fork the main
thread's history.
The solution here is to explicitly store a new `parent_thread_id` on
`SessionMeta`, alongside `forked_from_id` which already exists. While
we're at it, also expose it in the app-server protocol on the `Thread`
object.
A thread->subagent relationship and a fork of thread history are
orthogonal concepts.
## What Changed
- Added top-level `parent_thread_id` persistence on `SessionMeta` and
runtime/session plumbing through `SessionConfiguredEvent`,
`CodexSpawnArgs`, `SessionConfiguration`, `ThreadConfigSnapshot`,
`TurnContext`, and `ModelClient`.
- Made turn metadata, request headers, analytics, and subagent-start
events read the separate runtime/top-level parent field instead of
deriving general parent lineage from `SessionSource` or
`forked_from_thread_id`.
- Passed parent lineage separately at delegated subagent, review,
guardian, agent-job, and multi-agent spawn construction sites;
copied-history fork lineage remains derived only from `InitialHistory`.
- Persisted and exposed parent lineage through rollout/thread-store
projections and app-server v2 `Thread.parentThreadId`.
- Updated app-server README text and regenerated app-server schema
fixtures for the additive `parentThreadId` response field.
## Why
This PR is stacked on #24918, which moves goal steering onto
source-labeled internal model context fragments. Active-turn goal
steering should use the same running-turn injection path as other
runtime steering, so those fragments enter the pending input queue as
`ResponseItem`s through the existing
[`Session::inject_if_running`](8d6f6cdf69/codex-rs/core/src/session/inject.rs (L12-L27))
behavior instead of through a goal-specific conversion wrapper.
## What Changed
- Exposes a narrow `CodexThread::inject_if_running` bridge for callers
that only hold a thread handle.
- Changes `ext/goal` active-turn steering to pass `ResponseItem`s
directly.
- Builds goal steering prompts as contextual internal model context
`ResponseItem`s before injecting them into the running turn.
## Testing
Not run locally; PR metadata update only.
## Summary
Adds an optional `clientId` field to app-server v2 `UserInput` and
carries it through the core `UserInput` model so clients can correlate
echoed user input items without relying on payload equality.
## Details
- Adds `client_id: Option<String>` to core `UserInput` variants.
- Exposes the v2 app-server field as `clientId` on the wire and in
generated TypeScript.
- Preserves the id when converting between app-server v2 and core
protocol types.
- Regenerates app-server schema fixtures.
## Validation
- `just fmt`
- `just write-app-server-schema`
- `cargo test -p codex-app-server-protocol`
- `cargo test -p codex-protocol`
- `just fix -p codex-app-server-protocol`
- `just fix -p codex-protocol`
- `git diff --check`
WIll make it easier to uprev when the new draft spec is supported.
Also updates reqwest where needed for compatibility but doesn't update
it everywhere since this is already a large diff.
The new version of rmcp handles certain kinds of authentication failures
differently, this patch includes support for identifying the failing scope
in a WWW-Authenticate header.
## 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.
**Stack position:** [5 of 7]
## Summary
This PR adds `Op::ThreadSettings`, a queued settings-only update
mechanism for changing stored thread settings without starting a new
turn. It also removes the legacy `Op::OverrideTurnContext` in the same
layer, so reviewers can see the replacement and deletion together.
## Changes
- Add `Op::ThreadSettings` for settings-only queued updates.
- Emit `ThreadSettingsApplied` with the effective thread settings
snapshot after core applies an update.
- Route settings-only updates through the same submission queue as user
input.
- Migrate remaining `OverrideTurnContext` tests and callers to the
queued `Op::ThreadSettings` path.
- Delete `Op::OverrideTurnContext` from the core protocol and submission
loop.
This stack addresses #20656 and #22090.
## Stack
1. [1 of 7] [Add thread settings to
UserInput](https://github.com/openai/codex/pull/23080)
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) (this PR)
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)
**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)
## Why
Pending model input was split across `Session`, `TurnState`, and the
agent mailbox. That made it easy for new paths to manage queued user
input or mailbox delivery outside the intended ownership boundary.
This PR consolidates the model-facing input lifecycle behind the session
input queue so turn-local pending input, next-turn queued items, and
mailbox delivery coordination are owned in one place.
## What Changed
- Added `session/input_queue.rs` to own pending input queues and mailbox
delivery coordination.
- Removed the standalone `agent/mailbox.rs` channel wrapper and store
mailbox items directly in the input queue.
- Moved pending-input mutations off `TurnState`; `TurnState` now exposes
the queue-owned storage directly for now.
- Routed abort cleanup, mailbox delivery phase changes, next-turn queued
items, and active-turn pending input through `InputQueue`.
- Boxed stack-heavy agent resume/fork startup futures that the refactor
pushed over the default test stack.
- Updated session, task, goal, stream-event, and multi-agent call sites
and tests to use the new queue ownership.
## Verification
- `cargo test -p codex-core --lib agent::control::tests`
- `cargo test -p codex-core --lib
agent::control::tests::resume_closed_child_reopens_open_descendants --
--exact`
- `cargo test -p codex-core --lib
agent::control::tests::spawn_agent_fork_last_n_turns_keeps_only_recent_turns
-- --exact`
- `cargo test -p codex-core --lib
agent::control::tests::resume_thread_subagent_restores_stored_nickname_and_role
-- --exact`
- `cargo test -p codex-core` was also run; it completed with 1814
passed, 4 ignored, and one timeout in
`agent::control::tests::resume_thread_subagent_restores_stored_nickname_and_role`,
which passed when rerun in isolation.
## Why
Extension lifecycle hooks sit on the host/extension boundary, but the
current trait surface only allows synchronous callbacks. That forces
extensions that need to seed, rehydrate, observe, or flush
extension-owned state during thread and turn transitions to either block
inside the callback or move async work into separate host plumbing.
This PR makes those lifecycle callbacks awaitable so extension
implementations can perform async work directly at the lifecycle point
where the host already has the relevant session, thread, or turn stores
available.
## What changed
- Makes `ThreadLifecycleContributor` and `TurnLifecycleContributor`
async in `codex-extension-api`.
- Awaits thread start/resume/stop and turn start/stop/abort lifecycle
callbacks from `codex-core`.
- Updates the guardian and memories extensions to implement the async
lifecycle trait surface.
- Updates the existing lifecycle tests to use async contributor
implementations.
- Adds `async-trait` to the crates that now expose or implement these
async object-safe lifecycle traits.
## Testing
- Existing `codex-core` lifecycle tests were updated to cover async
implementations for thread stop and turn abort ordering.
## 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
## Summary
- add a scoped level_id to ExtensionData and expose it through
level_id()
- remove thread_id/turn_id parameters from extension contributor inputs
where the scoped ExtensionData already carries that identity
- move turn-scoped extension data onto TurnContext so token usage and
lifecycle contributors can share the same turn store
## Testing
- cargo check -p codex-extension-api -p codex-core --tests
- cargo test -p codex-extension-api
- cargo test -p codex-guardian
- cargo test -p codex-core --lib
record_token_usage_info_notifies_extension_contributors
- cargo test -p codex-core --lib
submission_loop_channel_close_emits_thread_stop_lifecycle
- cargo test -p codex-core --lib
submission_loop_channel_close_aborts_active_turn_before_thread_stop_lifecycle
- just fix -p codex-extension-api
- just fix -p codex-guardian
- just fix -p codex-core
- just fmt
## Note
- Attempted cargo test -p codex-core; it aborted in
agent::control::tests::spawn_agent_fork_last_n_turns_keeps_only_recent_turns
with the existing stack overflow before the full suite completed.
## Why
Extensions that need thread-scoped state currently only get a start-time
callback. That is enough for seeding stores, but it leaves the host
without a shared extension seam for later thread rehydrate and flush
work as thread ownership evolves. This PR turns that start-only seam
into a host-owned thread lifecycle contributor contract so
extension-private state can stay behind the extension API instead of
leaking extra orchestration through core.
## What changed
- Replaced `ThreadStartContributor` with `ThreadLifecycleContributor`
and added typed lifecycle inputs for thread start, resume, and stop. The
contract lives in
[`contributors/thread_lifecycle.rs`](d0e9211f70/codex-rs/ext/extension-api/src/contributors/thread_lifecycle.rs (L1-L64)).
- Kept the existing start-time behavior intact by routing session
construction through `on_thread_start`.
- Invoked `on_thread_stop` during session shutdown before thread-scoped
extension state is dropped, while isolating contributor failures behind
warning logs.
- Migrated `git-attribution` and `guardian` onto the lifecycle
registration path.
- Renamed the extension registry plumbing from start-specific
contributors to lifecycle-specific contributors.
## Notes
`on_thread_resume` is introduced at the API boundary here so extensions
can target the final lifecycle shape; host resume dispatch can be wired
where that runtime path is finalized.
## Why
While investigating `codex exec hi` startup latency, the useful
questions were not "is startup slow?" but "which durable bucket is slow
in production?"
The path we observed has a few distinct stages:
1. `thread/start` creates the session
2. startup prewarm builds the turn context, tools, and prompt
3. startup prewarm warms the websocket
4. the first real turn resolves the prewarm
5. the model produces the first token
Before this PR, production telemetry had some of the raw measurements
already:
- aggregate startup-prewarm duration / age-at-first-turn metrics
- TTFT as a metric
- websocket request telemetry
But there was no coherent production event stream for the startup
breakdown itself, and TTFT was metric-only. That made it hard to answer
the same latency questions from OpenTelemetry-backed logs without adding
one-off local instrumentation.
## What changed
Add durable production telemetry on the existing `SessionTelemetry`
path:
- new `codex.startup_phase` OTel log/trace events plus
`codex.startup.phase.duration_ms`
- new `codex.turn_ttft` OTel log/trace events while preserving the
existing TTFT metric
The startup phase event is emitted for the coarse buckets we actually
observed while running `exec hi`:
- `thread_start_create_thread`
- `startup_prewarm_total`
- `startup_prewarm_create_turn_context`
- `startup_prewarm_build_tools`
- `startup_prewarm_build_prompt`
- `startup_prewarm_websocket_warmup`
- `startup_prewarm_resolve`
These phases are intentionally low-cardinality so they remain safe as
production telemetry tags.
## Why this shape
This keeps the instrumentation on the same production path as the rest
of the session telemetry instead of adding a local debug-only trace
mode. It also avoids changing startup behavior:
- prewarm still runs
- no control flow changes
- no extra remote calls
- no user-visible behavior changes
One boundary is intentional: very early process bootstrap that happens
before a session exists is not included here, because this PR uses
session-scoped production telemetry. The expensive buckets we were
trying to understand after `thread/start` are now covered durably.
## Verification
- `cargo test -p codex-otel`
- `cargo test -p codex-core turn_timing`
- `cargo test -p codex-core
regular_turn_emits_turn_started_without_waiting_for_startup_prewarm`
- `cargo test -p codex-core
interrupting_regular_turn_waiting_on_startup_prewarm_emits_turn_aborted`
- `cargo test -p codex-app-server thread_start`
- `just fix -p codex-otel -p codex-core -p codex-app-server`
I also ran `cargo test -p codex-core`; it built successfully and then
hit an existing unrelated stack overflow in
`tools::handlers::multi_agents::tests::tool_handlers_cascade_close_and_resume_and_keep_explicitly_closed_subtrees_closed`.
## Why
PR #21460 reverted the earlier move of skills change watching from
`codex-core` into app-server. This reapplies that boundary change so
app-server owns client-facing `skills/changed` notifications and core no
longer carries the watcher.
## What
- Restore the app-server `SkillsWatcher` and register it from thread
listener setup.
- Remove the core-owned skills watcher and its core live-reload
integration surface.
- Restore app-server coverage for `skills/changed` notifications after a
watched skill file changes.
## Validation
- `cargo test -p codex-app-server --test all
suite::v2::skills_list::skills_changed_notification_is_emitted_after_skill_change
-- --exact --nocapture`
- `cargo test -p codex-core --lib --no-run`
## Why
App-server config writes were leaving existing threads partially stale.
After a config mutation, the app-server told each live thread to run
`Op::ReloadUserConfig`, but that path only re-read the user
`config.toml` layer. Settings that came from the app-server's
materialized config snapshot did not propagate to existing threads until
restart.
This change prevent a FS access from `core` for CCA.
## What changed
- add `CodexThread::refresh_runtime_config()` and
`Session::refresh_runtime_config()` so the app-server can push a freshly
rebuilt config snapshot into a live thread
- rebuild the latest config with each thread's `cwd` after config
mutations, then refresh the thread from that snapshot instead of asking
it to reload only `config.toml`
- keep session-static settings unchanged during refresh, while updating
runtime-refreshable state such as the config layer stack,
`tool_suggest`, and derived hook/plugin/skill state
- keep `reload_user_config_layer()` as the file-backed fallback for
legacy local reload flows, but route the shared refresh logic through
the new runtime refresh path
## Testing
- add a session test that verifies `refresh_runtime_config()` rebuilds
hooks from refreshed config
- add a session test that verifies runtime-refreshable fields update
while session-static settings like `model` and `notify` stay unchanged
---------
Co-authored-by: Codex <noreply@openai.com>
## Why
Skills update notifications are app-server API behavior, but the watcher
lived in `codex-core` and surfaced through
`EventMsg::SkillsUpdateAvailable`. Moving the watcher out keeps core
focused on thread execution and lets app-server own both cache
invalidation and the `skills/changed` notification.
## What changed
- Added an app-server-owned skills watcher that watches local skill
roots, clears the shared skills cache, and emits `skills/changed`
directly.
- Registers skill watches from the common app-server thread listener
attach path, including direct starts, resumes, and app-server-observed
child or forked threads.
- Stores the `WatchRegistration` on `ThreadState`, so listener
replacement, thread teardown, idle unload, and app-server shutdown
deregister by dropping the RAII guard.
- Removed `EventMsg::SkillsUpdateAvailable`, the core watcher, and the
old core live-reload test.
- Extended the app-server skills change test to verify a cached skills
list is refreshed after a filesystem change without forcing reload.
## Validation
- `cargo check -p codex-core -p codex-app-server -p codex-mcp-server -p
codex-rollout -p codex-rollout-trace`
- `cargo test -p codex-app-server
skills_changed_notification_is_emitted_after_skill_change`
## 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>
