## 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`
## 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.
## Why
`ActiveTurn` already runs at most one task: starting a task requires
that no task is present, and replacement aborts existing work first.
Representing that state as an `IndexMap` leaves a multi-task shape for a
single-task invariant and makes each lifecycle lookup operate like a
collection lookup.
The slot remains optional because goal continuation uses an empty active
turn as a reservation while deciding whether to start continuation work.
## What changed
- Replace `ActiveTurn.tasks` with `task: Option<RunningTask>`.
- Update task abort/completion, session lookup and steering, input-queue
matching, goal reservation, and network-approval lookup to operate on
the singular slot.
- Mutate the singular task slot directly instead of retaining
collection-era add/remove/take helpers.
- Record token usage on the completing active task span without a
regular-task-only opt-in flag.
## Validation
- `cargo test -p codex-core --lib session::tests::steer_input`
- `cargo test -p codex-core --lib
session::tests::abort_empty_active_turn_preserves_pending_input`
- `cargo test -p codex-core --lib
session::tests::queued_response_items_for_next_turn_move_into_next_active_turn`
- `cargo test -p codex-core --lib
session::tests::active_goal_continuation_runs_again_after_no_tool_turn`
- `cargo test -p codex-core --lib
session::tests::abort_regular_task_emits_turn_aborted_only`
- `cargo test -p codex-core --lib session::input_queue::tests`
## Why
Steered input was queued as a `ResponseInputItem`, then parsed back into
a user message before recording. That path loses information that only
exists on `UserInput`, such as UI text elements.
This change keeps turn-local pending input typed as either original
`UserInput` or existing response items, so steered user input reaches
user-message recording without being reconstructed from a response item.
## What changed
- Add `TurnInput` for active-turn pending input.
- Queue `Session::steer_input` as `TurnInput::UserInput`.
- Run pending-input hook inspection only for `TurnInput::UserInput`.
- Process drained pending input item by item: accepted items are
recorded, blocked items append hook context and are skipped.
- Remove the pending-input prepend/requeue path.
## Validation
- `just fmt`
- `just fix -p codex-core`
- `RUST_MIN_STACK=16777216 cargo test -p codex-core --lib
session::tests::task_finish_emits_turn_item_lifecycle_for_leftover_pending_user_input
-- --nocapture`
- `RUST_MIN_STACK=16777216 cargo test -p codex-core --lib steer_input`
- `RUST_MIN_STACK=16777216 cargo test -p codex-core --lib pending_input`
- `RUST_MIN_STACK=16777216 cargo test -p codex-core --test all
pending_input`
- `RUST_MIN_STACK=16777216 cargo test -p codex-core` (unit tests passed:
1835 passed, 0 failed, 4 ignored; integration `all` target failed due
missing helper binaries such as `codex`/`test_stdio_server` plus
unrelated MCP/search/code-mode expectations)
## 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.
Alexi Christakis