## What changed
- Inherit paginated history mode when spawning or forking a subagent from a paginated parent.
- Load the parent's model context when forking and persist it as an inherited rollout prefix, while excluding that prefix from the child's projected turns, items, and metadata.
- Record the boundary between inherited context and child history, and reject partially initialized paginated subagent rollouts on resume.
- Resume paginated subagents from their stored model context instead of legacy rollout history.
## Testing
Added coverage for fresh and forked paginated subagents, compacted-history forks, model-context resume, inherited-prefix projection, metadata isolation, and incomplete-prefix detection.
GitOrigin-RevId: e57dc37c29aa4aaaf57b052b991be591d730e5ba
## Why
Host skills can change after a thread starts. Subsequent turns need the updated
catalog without reinjecting an unchanged catalog on every turn.
## What changed
- Register the host skill provider in app-server and project its catalog through
a dedicated World State section.
- Render host skills with the existing metadata budget and usage instructions,
including skill-root aliases when available.
- Suppress the legacy host catalog and contextual fragment when World State owns
the catalog, while preserving host skills for explicit and shadow selection.
## Testing
Added an app-server test that installs a host skill at runtime and verifies the
catalog updates once and remains stable on the following turn.
GitOrigin-RevId: 4cacc6b2258fc3cab8499fbdf9aa6ab0324ec10d
## What changed
- Replace the combined `Codex` wrapper with an `Arc<Session>` and a dedicated
`SessionIo` handle for submissions, events, status, and loop termination.
- Make `Session::spawn` return the session and I/O handle separately, and have
`CodexThread` own both.
- Update thread management, delegated sessions, guardian reviews, and agent
control to use the appropriate session or I/O interface.
GitOrigin-RevId: 8523bad7e7366e2969fd0cc3849b4247b141427a
## What changed
- Add per-sandbox-mode permission messages to `ModelMessages` and preserve them when applying model configuration overrides.
- Use the selected catalog message in permission instructions, substituting `{{ network_access }}` with the active network policy. Fall back to the existing sandbox text when no override is provided, and allow an empty override to omit only the sandbox section.
- Apply catalog permission messages when a session starts and when its model changes.
## Testing
- Cover catalog deserialization, mode selection, network substitution, fallback and empty-message behavior, remote model catalogs, and model changes.
GitOrigin-RevId: cd5ed3aee3155dca0e7b2358c0f09bae73236856
## Why
Multi-environment turns can run against different filesystems, so a single
thread-wide workspace-root list cannot accurately describe every selected
environment.
## What changed
- Add optional `runtimeWorkspaceRoots` to each app-server environment selection.
Omitted roots default to that environment's `cwd`, while an empty list selects
no roots.
- Carry environment-native roots through turn selection, model-visible context,
permission materialization, and tool sandboxing.
- Keep the top-level `runtimeWorkspaceRoots` field as a compatibility input when
constructing default environment selections; explicit selections use their
own roots.
## Testing
- Cover thread and turn API defaults, overrides, empty roots, and schema
round-tripping.
- Verify foreign roots remain model-visible and remote execution applies the
target environment's roots before sandbox selection.
GitOrigin-RevId: c6e7a62883c45c676c153055f46a55ee15a323a4
## Why
Network proxy enforcement on Windows requires the elevated sandbox backend. Silently selecting that backend for an unelevated configuration makes the effective sandbox differ from the configured mode.
## What changed
- Reject enabled network proxy configurations on Windows unless managed requirements allow only the elevated sandbox and `windows.sandbox` resolves to `"elevated"`.
- Preserve the configured sandbox backend during execution and validate proxy compatibility at config loading, sandbox setup, and process launch boundaries.
- Defer this validation during cloud-config bootstrap so authoritative managed requirements can be loaded first.
- Do not start or expose disabled Windows proxies, and render transitions to disabled networking as `<network enabled="false"></network>`.
## Testing
- Cover Windows requirement and sandbox compatibility matrices, bootstrap behavior, backend selection, disabled proxy handling, and environment-context updates.
GitOrigin-RevId: bfa1dda98594e0db61883f8e7f65bd560e3453e6
## Why
OAuth metadata discovery for an optional HTTP MCP server can stall, delaying
`thread/start` even though that server is not required.
## What changed
- Remove eager MCP authentication-status discovery from session and connection
manager startup.
- When an MCP connection reports an authentication error, inspect configured and
stored credentials locally to preserve login and reauthentication failure
reasons without making another discovery request.
- Continue using server configuration directly for startup error messages and
timeout hints.
## Testing
Add an app-server regression test with an optional HTTP MCP endpoint that accepts
a connection but never responds, and verify that `thread/start` completes without
waiting for its configured startup timeout.
GitOrigin-RevId: 56fe0188cc1ceaf746b0b65e8b7dd1fd2e13420d
## What changed
- Move the Codex Apps tool cache into a reusable `codex-connectors` runtime manager keyed by account and workspace.
- Represent cached tools as atomically published snapshots with refresh timestamps while preserving the newest accepted fetch generation.
- Harden disk persistence with bounded reads, atomic file replacement, and serialized writes so an older fetch cannot overwrite newer state.
## Testing
Add coverage for identity isolation, snapshot timestamps, oversized cache files, atomic replacement, and concurrent persistence ordering.
GitOrigin-RevId: 5ea2234469daae3abf54b030244c3251de62ca5a
## What changed
- Add a `ResponseItemId` type that generates item-specific prefixes with UUIDv7 suffixes and use it across response items.
- Keep deserialization permissive for legacy histories, but omit empty or unprefixed item IDs from HTTP and WebSocket requests.
- Export the new type in the generated TypeScript protocol schema.
## Testing
- Cover prefixed ID generation, legacy deserialization, prefix recognition, and outbound request filtering.
GitOrigin-RevId: 0209fe430c826d0ae88bc4648652c4ebf390c4a4
## What changed
- Add an optional `error` payload to `TurnCompleteEvent` and omit it when a turn completes without an error.
- Preserve the full terminal `ErrorEvent` through the turn lifecycle so the completion event includes the same error details emitted separately by `EventMsg::Error`.
## Testing
- Extend the stream-error integration test to verify that `TurnCompleteEvent` contains the emitted error and that the next turn can still proceed.
GitOrigin-RevId: 8d32942a44132763076130102d8b89ab356d59d0
## Description
This PR makes new threads with `history_mode = "paginated"` persist
`ItemCompleted(item: <turn_item>)` in their rollout JSONL file.
Legacy threads keep persisting the existing legacy events. Because the
format is selected per thread, a rollout is either legacy or paginated;
we do not need to support mixed rollouts containing both
representations.
This PR depends on [#31473](https://github.com/openai/codex/pull/31473).
## Why
Paginated thread history needs stable turn/item IDs and completed item
snapshots so the later SQLite projector can materialize appended rollout
JSONL without rebuilding the whole thread.
Keeping the legacy persistence policy unchanged avoids changing
historical rollouts or the readers that still consume them.
## What changed
- Made rollout filtering history-mode aware. Paginated threads keep
completed canonical `ItemCompleted` events and drop their redundant
legacy projections; legacy threads keep the existing event set.
- Made forks inherit the source thread history mode, so copied legacy
history is never filtered as paginated.
- Made paginated threads assign IDs to locally-created response items
even when `Feature::ItemIds` is off, and reject streamed output items
that arrive without server IDs.
- Updated legacy turn replay, rollout list/search, and SQLite metadata
extraction to understand completed canonical user-message items.
## Why
A thread resumed without an explicit reviewer could pick up the reviewer
from the current config instead of preserving the reviewer already in
use by the thread. After an app restart, this meant a thread running
with auto review could silently switch back to user review, and the next
turn could continue under the wrong reviewer.
## What changed
Persist the effective reviewer with each turn and restore the latest
persisted value when the thread resumes. If the resume request
explicitly provides a reviewer, that value still takes precedence.
## Test plan
- Added a regression test that starts a thread with auto review, records
a turn, restarts with user review in config, resumes without an
override, and verifies that auto review is preserved.
- `just test -p codex-protocol`
- `just test -p codex-state`
- `just test -p codex-rollout`
- `just test -p codex-app-server
thread_resume_preserves_persisted_approvals_reviewer`
- Clippy for the affected crates
### summary
We want to pause code-mode from yielding back to the model when a
subcommand triggers an approval prompt. This means that all of these
previously inline blocking requests should also take out a
ElicitationService registration.
This also does some plumbing refactoring to request patch approval to
make it match the other `request_*_approval` methods in that it blocks
on the approval in the function instead of returning the oneshot
channel, this affords our ability to encapsulate the ElicitationService
registration via RAII.
Adds tests to confirm the blocking behavior for code_mode both in suite
tests and that the session holds them.
## Description
This PR moves review-mode markers onto canonical `TurnItem` lifecycle:
- `TurnItem::EnteredReviewMode`
- `TurnItem::ExitedReviewMode`
Core now emits `ItemStarted` / `ItemCompleted` for both. The completed
items map back into the existing `EnteredReviewMode` /
`ExitedReviewMode` events, so raw core event consumers and legacy
rollout persistence keep seeing the old events.
This is the compatibility layer needed before paginated rollouts persist
review markers as `ItemCompleted(TurnItem)`.
## Why
Review markers were one of the remaining app-server thread items created
directly from legacy events. Giving them canonical items lets paginated
history persist stable turn/item IDs without changing legacy rollouts.
## What changed
- Added canonical review-mode `TurnItem`s and switched review flow to
emit their lifecycle.
- Added completed-item → legacy review event mappings with stable
turn/item IDs.
- Switched app-server live notifications to the generic canonical item
path and kept legacy replay compatible with old payloads.
- Updated `ThreadHistoryBuilder` to replay canonical review items even
though review turns still do not emit `TurnStarted`.
## Why
Approval guidance is currently assembled entirely by the client. Model
Messages V2 needs model catalogs to provide model-specific `on_request`
guidance for both user-reviewed and auto-reviewed approval flows while
retaining the existing generated prompt as a compatibility fallback.
## What changed
- add nullable `on_request` and `on_request_auto_review` catalog
messages
- select the message matching the active approvals reviewer for
`on_request` policies
- replace the complete legacy approval section when the selected catalog
value exists, including support for an empty string that suppresses the
section
- retain legacy rendering when the object or selected key is absent, and
for non-`on_request` policies
- preserve approval messages when base-instruction or personality
overrides clear instruction templates
- refresh permissions instructions when the active model changes
- pass catalog messages through initial and incremental permissions
construction
## Relationship to reviewer persistence
PR #31309 independently persists the approvals reviewer in turn context
and refreshes permissions when that reviewer changes. This PR is based
directly on `main` and does not duplicate that rollout migration; once
both land, reviewer switches will also select and append the new catalog
variant.
## Testing
- `just test -p codex-protocol`
- `just test -p codex-prompts`
- `just test -p codex-models-manager`
- `just test -p codex-core permissions_messages`
## Description
This PR adds legacy `EventMsg` mappings for the `TurnItem` types
introduced in [#30282](https://github.com/openai/codex/pull/30282):
- `CommandExecution`
- `DynamicToolCall`
- `CollabAgentToolCall`
- `SubAgentActivity`
When their producers move to canonical `ItemStarted` / `ItemCompleted`,
raw core event consumers can still receive the existing begin/end-style
events. The canonical item lifecycle remains the live source of truth.
We also record the mapped legacy events in rollout trace so the producer
migration preserves the existing tool-runtime trace entries.
## Why
This is the compatibility layer for the follow-up producer migrations.
Splitting it out first keeps each producer PR small and keeps the legacy
mapping in one place.
## What changed
- Added `TurnItem` → legacy `EventMsg` mappings in
`protocol/src/legacy_events.rs`.
- Added the command execution status conversion used by the exec
mapping.
- Added focused coverage for command execution and dynamic tool
mappings.
## Why
Codex currently omits a configured `service_tier` when the selected
model's catalog entry does not advertise support for it. That fallback
is silent, so users can unknowingly send requests at the default tier
instead. This makes cases such as #26604 difficult to diagnose.
## What changed
- Emit the shared core `Warning` event during session startup when a
configured service tier will be omitted because the initial model does
not advertise support for it.
- Do not warn on later model or service-tier changes, which keeps
warning emission stateless and avoids client-specific handling.
- Keep the existing request filtering behavior unchanged.
## Validation
- `just test -p codex-core unsupported_service_tier`
- `just test -p codex-core
unsupported_configured_service_tier_warns_at_session_start`
### Manual validation
- Launched the real TUI with the bundled catalog, where `gpt-5.5`
advertises the `priority` tier but not `flex`, and configured
`service_tier = "flex"`.
- Confirmed the unsupported-tier warning appeared exactly once during
startup.
- Submitted two turns through a local Responses API SSE stub; both
received mock replies and neither emitted another warning.
- Inspected both captured `/v1/responses` request bodies and confirmed
that neither contained a `service_tier` field.
- Repeated the two-turn TUI flow against the live Responses API; both
turns completed and the warning was not repeated.
## Why
Generic Apps guidance is emitted only while building static initial
context. If the Apps MCP is unavailable then and recovers later in the
same turn, its tools can become usable without the model receiving the
guidance for using them.
## What
- move generic Apps guidance into a persisted `apps_instructions` World
State section
- derive availability from the request's MCP runtime while preserving
the existing feature, auth, orchestrator-MCP, and config gates
- recognize legacy and retained Apps fragments so resume and compaction
do not duplicate guidance
- register Apps guidance as rollback-trimmable context
- remove the old static injection path and its now-unused connector
helper
- keep tool construction on its existing independent `list_all_tools()`
read rather than adding a request-wide cache; a reconnect between the
two reads can differ for one request and reconciles on the next request
Apps and plugin guidance now render after the remaining static
host-skills block, with Apps before Plugins.
## Testing
- `just fmt`
- `just test -p codex-core apps_instructions`
- `just test -p codex-core
apps_guidance_appears_after_background_recovery_within_a_turn`
- `just test -p codex-core
drop_last_n_user_turns_trims_context_updates_above_rolled_back_turn`
## Why
Make it easier to measure the performance of different parts of skill
loading.
## What
- Add spans for step-context capture, world-state construction, executor
catalog snapshot/root loading, and environment skill loading.
- Record the discovered environment skill count.
- Trace outbound exec-server requests with client kind and RPC method
fields.
- Update trace propagation tests to assert that requests keep the parent
trace id while creating their own child span.
## 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.
## Why
Generic plugin guidance is currently emitted only with initial context
from host plugin state. An executor-selected plugin can become available
later in the same turn, making its skills and tools usable without ever
telling the model how plugin capabilities should be used.
## What
- project every ready selected plugin package, including skill-only
plugins
- carry plugin availability with the exact MCP runtime projection while
preserving MCP manager reuse when servers and connectors are unchanged
- move generic plugin guidance from the static initial-context path into
persisted World State
- recognize legacy and retained plugin fragments so resume and
compaction do not duplicate guidance
## Testing
- `just test -p codex-mcp-extension`
- `just test -p codex-core plugins_instructions`
- `just test -p codex-core
plugin_availability_change_reuses_the_mcp_manager`
- `just test -p codex-app-server --test all selected_capabilit`
## Why
Multi-agent V2 normally derives its mode instructions from reasoning
effort: Ultra enables proactive delegation, while other efforts require
an explicit request. Some deployments need to provide one configured
delegation policy that replaces those built-ins and remains stable when
reasoning effort changes.
## What changed
- Add `features.multi_agent_v2.multi_agent_mode_hint_text` alongside the
existing root and subagent hint settings.
- Treat any configured value, including an empty string, as
`MultiAgentMode::Custom(hint_text)`, so the configured text replaces the
built-in explicit-only and proactive policies.
- Persist the full custom variant and hint text in the turn-context
snapshot, so the durable comparison baseline detects both
reasoning-effort changes and configured policy-text changes.
- Preserve the existing explicit-only/proactive behavior when the
setting is absent.
- Replace the ambiguous `MultiAgentMode::None` variant with
`MultiAgentMode::Custom(String)` in new rollouts and API schemas. A
compatibility wire type maps legacy serialized `none` values to
`Custom("")` when resuming existing rollouts.
- Regenerate the config and app-server schemas.
## Configuration examples
The distinction is whether `multi_agent_mode_hint_text` is present. An
empty string is still a configured value and intentionally suppresses
the built-in mode instructions.
### Unset: preserve existing effort-derived behavior
```toml
[features.multi_agent_v2]
enabled = true
# multi_agent_mode_hint_text is omitted
```
- Ultra reasoning uses the built-in proactive delegation instructions.
- Other reasoning efforts use the built-in explicit-request-only
instructions.
### Empty: suppress all mode hint text
```toml
[features.multi_agent_v2]
enabled = true
multi_agent_mode_hint_text = ""
```
This selects effective mode `custom` at every reasoning effort and
injects an empty mode body, suppressing both built-in policies.
### Set: always use the configured text
```toml
[features.multi_agent_v2]
enabled = true
multi_agent_mode_hint_text = "Delegate to subagents when it will materially improve the result."
```
This selects effective mode `custom` at every reasoning effort and
injects the configured text verbatim instead of either built-in policy.
## Verification
- `just test -p codex-core multi_agent_mode`
- Covers a configured hint across High and Ultra reasoning efforts and
verifies the full custom hint is recorded for both turns.
- Covers an empty-string override suppressing both built-in instruction
bodies.
- `just test -p codex-protocol -p codex-app-server-protocol`
- Covers legacy `none` turn-context deserialization as `Custom("")` and
verifies the regenerated schemas.
## Why
[#30867](https://github.com/openai/codex/pull/30867) makes
`submit_inter_agent_communication` the common outbound sink for
multi-agent v2 communications. This follow-up uses that single point to
log every communication lifecycle without requiring new hooks as spawn,
messaging, follow-up, or result paths evolve.
For each communication, the logs need to identify its type, sender and
receiver threads, and content, while correlating the successful send
with receipt by the destination mailbox. The logging path must not query
externally supplied time providers because those calls can be expensive
for app-server clients.
## What changed
- Added structured `INFO` events on the OpenTelemetry-exported
`codex_otel.agent_communication` target for `spawn`, `message`,
`followup`, and `result` communications.
- Logged successful sends from `submit_inter_agent_communication` with
the communication kind, sender and receiver thread IDs, content, and
submission ID.
- Logged receives after the communication has been enqueued in the
receiver mailbox, using the same submission ID.
- Avoided time-provider calls and other asynchronous work in the logging
path.
- Narrowed ordinary spawn and send-input APIs to `Vec<UserInput>` so
`Op::InterAgentCommunication` cannot bypass the context-bearing
centralized path.
The refactor does not change submission IDs, capacity checks, last-task
bookkeeping, mailbox ordering, protocol types, rollout data, or
model-visible context.
## Event shape
Illustrative JSON representation of the two independently emitted
records:
```json
[
{
"event.name": "codex.agent_communication",
"communication_id": "019f20e1-40d1-7890-a123-456789abcdef",
"kind": "spawn",
"state": "send",
"sender_thread_id": "019f20df-fbe1-7890-a123-456789abcdef",
"receiver_thread_id": "019f20e1-3f79-7890-a123-456789abcdef",
"content": "inspect the repository"
},
{
"event.name": "codex.agent_communication",
"communication_id": "019f20e1-40d1-7890-a123-456789abcdef",
"state": "receive"
}
]
```
Consumers join the receive record to the send record by
`communication_id` for the immutable communication metadata.
## Testing
- Extended the existing end-to-end multi-agent v2 spawn test to verify
content, both thread IDs, and a correlated send/receive submission ID.
- Re-ran focused control and handler coverage for direct messages,
follow-up tasks, and completion results.
## Summary
- add a false-by-default `include_skills_usage_instructions` model
metadata field
- enable the field for the bundled `gpt-5.5` model metadata
- consume the metadata in both core and extension skill rendering
- remove hardcoded legacy-model matching and its marker plumbing
## 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.
## Summary
- add the `code_mode_host` feature flag and select
`ProcessOwnedCodeModeSessionProvider` in `CodeModeService` when enabled
- initialize code-mode sessions lazily so a missing host reports a tool
error without failing thread startup
- resolve `codex-code-mode-host` beside the running Codex binary by
default while preserving `CODEX_CODE_MODE_HOST_PATH` as an override
- add unit and end-to-end coverage for host resolution and graceful
missing-host behavior
## Why
This wires the process-owned session client from #30112 into the core
service behind an opt-in rollout gate. Packaged Codex installations can
place the helper in the same `bin` directory as the main executable
without relying on `PATH`, while development and custom installations
can continue to override the helper path.
## Stack
- Depends on #30112
- Base branch: `cconger/process-owned-session-runtime-4-client`
## Validation
Build `codex` and `codex-code-mode-host`
`CODEX_CODE_MODE_HOST_PATH="$PWD/target/debug/codex-code-mode-host"
./target/debug/codex --enable code_mode_host`
## 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.
## Summary
- track user-like input and tool-output boundaries in current-time
reminder state
- gate reminder injection when delivery_mode is
after_user_or_tool_output
- preserve interval debounce and forced reminders after context-window
changes
## Why
Training can request reminders only after user or tool-output items
while keeping the existing canonical pre-inference history-injection
path.
## Validation
- just test -p codex-core
current_time_reminders_can_follow_only_user_or_tool_outputs
- just test -p codex-core
current_time_reminders_follow_time_interval_and_persist_in_history
- just test -p codex-core
current_time_reminder_is_refreshed_after_compaction
- just fix -p codex-core
## Why
Helper threads such as task title generation can request a model ID that
is valid for the default OpenAI provider but unavailable from the active
provider. With Amazon Bedrock, `gpt-5.4-mini` is rejected while the
provider static catalog exposes Bedrock model IDs such as
`openai.gpt-5.5` and `openai.gpt-5.4`. This causes repeated background
404s and can surface a misleading turn error even when the main turn
succeeds.
Clients need an explicit way to ask app-server to resolve an unavailable
helper model to the active provider default. That fallback must remain
limited to providers with an authoritative static catalog so custom or
dynamically discovered model IDs are not rewritten based on an
incomplete catalog.
Fixes#28741.
## What changed
- Add the experimental `allowProviderModelFallback` option to
`thread/start`, defaulting to `false` to preserve existing behavior.
- Thread the option through thread creation and model selection.
- When enabled for a static model manager, preserve requested models
present in the catalog and replace unavailable models with the provider
default.
- Continue preserving explicit model IDs for dynamic model managers
without fetching a catalog solely to validate them.
- Document the new `thread/start` behavior in the app-server API
overview.
## Test
Temporary test-client harness:
```
ThreadStartParams {
model: Some("gpt-5.4-mini".to_string()),
allow_provider_model_fallback: true,
..Default::default()
}
```
Command:
```
CODEX_HOME=/tmp/codex-bedrock-thread-start-home \
CODEX_E2E_BEDROCK_THREAD_START_ONLY=1 \
./target/debug/codex-app-server-test-client \
--codex-bin ./target/debug/codex \
-c 'model_provider="amazon-bedrock"' \
send-message-v2 --experimental-api ignored
```
Relevant output:
```
> "method": "thread/start",
> "params": {
> "model": "gpt-5.4-mini",
> "modelProvider": null,
> "allowProviderModelFallback": true,
> ...
> }
< "result": {
< "model": "openai.gpt-5.5",
< "modelProvider": "amazon-bedrock",
< ...
< }
```
## Why
`selectedCapabilityRoots` is durable thread intent: “use this capability
root from environment `worker`.”
The important product assumption is:
> One environment ID always names the same logical executor and stable
contents.
`worker` does not silently change from executor A to an unrelated
executor B. The process-local connection handle for `worker` can still
be replaced while Codex is running, though, for example when
`environment/add` registers a fresh handle for the same logical
environment.
The thread should persist only the stable selection. Each model step
should pair that selection with the exact ready handle captured for that
step.
## The boundary
```text
persisted thread intent
plugin@1 -> environment "worker"
|
| capture the current step
v
model-step view
unavailable, or
plugin@1 + worker's exact captured ready handle
```
The environment ID is the stable identity and cache key. The
`Arc<Environment>` is only a process-local handle retained so consumers
of one model step use the same captured environment. It is never
persisted and it does not imply different environment contents.
## What changes
### Persist the stable selection
Selected roots are written into `SessionMeta` and restored with the
thread. Forked subagents inherit the same selections, including
bounded-history forks.
Only stable data is persisted: root ID, environment ID, and root path.
### Capture readiness together with the exact handle
The environment snapshot records:
```rust
environment_id -> Some(Arc<Environment>) // ready in this step
environment_id -> None // still starting in this step
```
This prevents readiness and execution from coming from different
registry snapshots.
For example:
```text
step snapshot: worker -> handle A, ready
environment/add: worker -> fresh handle B for the same logical environment
current step: plugin@1 still uses captured handle A
```
Without carrying handle A in the snapshot, the resolver could combine “A
was ready” with handle B and treat B as ready before it had finished
starting.
This does not change cache invalidation. Stable capability metadata
remains identified by environment ID and capability root. Replacing a
process-local handle under the same stable environment ID does not
invalidate or rediscover that metadata.
### Resolve availability per model step
- A ready captured environment produces resolved roots using its
captured handle.
- A starting, missing, or failed environment is omitted from that step.
- A selected lazy environment that is outside the turn's captured
environment set is asked to start, and a later step can observe it as
ready.
- No capability files are scanned here.
Transient transport disconnects remain the remote client's reconnect
concern. This PR models initial attachment/readiness; it does not add
live socket-connectivity state.
## Example
```text
thread selection: plugin@1 -> environment "worker"
step 1: worker is starting -> plugin@1 unavailable
step 2: worker is ready -> plugin@1 resolves through worker's captured handle
step 3: fresh local handle -> current step remains pinned; a later step captures its own view
```
Temporary unavailability does not discard the durable selection. Later
PRs can retain stable metadata caches while projecting only currently
available capabilities into model-visible World State.
## Compatibility
The app-server request shape does not change. Older rollouts without
`selected_capability_roots` deserialize to an empty list.
## Stack
1. **This PR:** persist stable selected roots and resolve them through
an exact model-step handle.
2. #29960: cache stable skill metadata and project available skills into
World State.
3. #29946: cache stable plugin declarations and manage the separate live
MCP runtime.
## 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
Persisting `WorldState` snapshots and patches is only useful if resume
and fork restore that exact comparison baseline. Rebuilding it from
`TurnContextItem` loses section state and can either repeat or suppress
model-visible updates.
This is the third PR in the WorldState persistence stack, built on
#29835.
## What
- Replay full WorldState snapshots and RFC 7386 patches through the
existing rollout reconstruction segments.
- Discard state from rolled-back turns and treat compaction as a
baseline reset.
- Hydrate `ContextManager` from the reconstructed snapshot on resume and
fork.
- Remove the synthetic `TurnContextItem` to WorldState conversion path.
- Leave legacy or malformed rollouts without a baseline so the next
update safely emits a full snapshot.
## Testing
- `just test -p codex-core world_state`
- `just test -p codex-core rollout_reconstruction_tests`
- `just fix -p codex-core`
- `just test -p codex-core` *(the changed tests passed; the full run
also hit unrelated existing/test-environment failures, primarily a
missing `test_stdio_server` binary)*
## 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
`WorldState` currently remembers its model-visible diff baseline only in
memory. That leaves no durable source for restoring the exact baseline
after resume, fork, rollback, or compaction.
This is the second PR in the WorldState persistence stack, built on
#29833 and following #29249. It records durable state transitions; the
next PR will replay them during rollout reconstruction.
## What
- Add a `world_state` rollout item containing either a full snapshot or
an RFC 7386 JSON Merge Patch.
- Persist a full snapshot after initial context and after compaction
establishes a new context window.
- Persist non-empty patches when later sampling steps or turns advance
the WorldState baseline.
- Write model-visible history before its matching WorldState record, so
an interrupted write can only cause a safe repeated update on replay.
- Preserve WorldState records for full-history forks while excluding
them from thread previews, metadata, and app-server history
materialization.
Older binaries read rollout lines independently, so they skip the
unknown `world_state` records while retaining the rest of the thread.
## Testing
- `just test -p codex-core
snapshot_merge_patch_changes_and_removes_nested_values`
- `just test -p codex-core
world_state_baseline_deduplicates_until_history_is_replaced`
- `just test -p codex-core
deferred_executor_compaction_preserves_then_updates_environment_once`
- `just test -p codex-protocol`
- `just test -p codex-rollout`
- `just test -p codex-state`
- `just test -p codex-thread-store`
- `just test -p codex-app-server-protocol`
## Why
`WorldState` currently keeps its diff baseline as live Rust objects
keyed by process-local `TypeId`. That baseline cannot be written to a
rollout or restored after resume, so Codex reconstructs an approximation
from `TurnContextItem`.
This is the first change in the WorldState persistence stack. It gives
every section a stable persisted identity and a compact serializable
comparison snapshot without changing rollout behavior yet.
## What changed
- Require each `WorldStateSection` to define a stable ID and
serializable snapshot type.
- Reject duplicate section IDs when constructing `WorldState`.
- Persist a dedicated environment comparison snapshot using
model-visible strings instead of runtime path types.
- Store only `WorldStateSnapshot` in `ContextManager`, removing the
parallel live-object baseline.
- Render diffs by restoring each section's typed snapshot; invalid
snapshots fall back to a full section render.
- Omit null object fields for future RFC 7386 patches while preserving
null values inside arrays.
Follow-up PRs will record full snapshots and merge patches, then restore
the baseline during resume, fork, and rollback.
## Test plan
- WorldState snapshot tests cover stable IDs, duplicate rejection, null
omission, and array preservation.
- Environment tests cover persistence-safe snapshot values and existing
diff rendering.
- ContextManager baseline deduplication and session context-update
persistence tests.
Related: #29249
## Why
This PR adds a configurable `<context_window_guidance>` developer
section immediately after `<context_window>`. Harness integrations need
this section to give the model deployment-specific instructions for
preparing for context-window transitions.
## What changed
- Add an optional `features.token_budget.guidance_message` config with a
1,000-byte runtime cap and generated schema support.
- Render configured guidance as a developer `ContextualUserFragment`
wrapped in `<context_window_guidance>` immediately after
`<context_window>`.
- Omit the section when guidance is unset, empty, or whitespace-only.
- Preserve the resolved value in config locks and classify persisted
guidance as contextual developer content.
- Add integration coverage for rendered content and ordering.
## Why
Core and tools need to request MCP elicitation without constructing
app-server wire payloads. The request should remain a neutral protocol
concept until app-server serializes it for a client.
## What changed
- Switched core and tools to
`codex_protocol::approvals::ElicitationRequest`.
- Derived turn and server context inside core instead of carrying
app-server request types through lower layers.
- Kept the app-server payload unchanged through an explicit boundary
conversion.
- Removed the remaining production app-server-protocol dependency from
tools.
## Stack
This is PR 5 of 6, stacked on [PR
#29723](https://github.com/openai/codex/pull/29723). Review only the
delta from `codex/split-connector-metadata-types`. Next: [PR
#29725](https://github.com/openai/codex/pull/29725).
## Validation
- `codex-core` MCP coverage passed: 87 tests.
- Tools elicitation and app-server round-trip coverage passed.
## Why
Inter-agent messages are recorded in live history as
`ResponseItem::AgentMessage`, but rollouts stored
`InterAgentCommunication` and rebuilt the response item during resume.
This made the rollout differ from the actual Responses history.
## What changed
- store the prepared `agent_message` response item directly
- keep `trigger_turn` in a small local metadata record for fork
truncation
- keep reading older `inter_agent_communication` rollout items
## Why
Fork-specific response items, including the subagent usage hint, are
appended directly to `InitialHistory::Forked`. This bypasses the normal
history insertion path that assigns missing response item IDs when
`Feature::ItemIds` is enabled, so the child could reconstruct and
persist those items without IDs.
## What changed
- When `Feature::ItemIds` is enabled, assign missing IDs to top-level
`ResponseItem`s while materializing `InitialHistory::Forked`, before
both reconstruction and persistence.
- Preserve existing IDs and use the same owned rollout items for live
history and persistence.
- Extract the existing single-item ID allocation logic for reuse by the
fork path.
- Add coverage that verifies a fork-only developer message receives the
same ID in live and persisted history with the feature enabled.
Normal history recording, compacted-history replacement, and fork
handling all continue to honor `Feature::ItemIds`. External-agent
imports, normal resume, and nested legacy compaction checkpoints are
unchanged.
## Testing
- `just test -p codex-core
record_initial_history_reconstructs_forked_transcript`
- `just test -p codex-core
record_initial_history_assigns_and_persists_id_for_forked_response_item`
## Why
`start_new_context_window` independently replaced in-memory history and
persisted a compacted checkpoint instead of using the shared
compacted-history path. That bypassed the centralized missing-item-ID
assignment when `item_ids` is enabled, so fresh context messages could
enter the new context window and its persisted replacement history
without IDs.
This follows up on the token-budget compaction reset flow introduced in
[#29743](https://github.com/openai/codex/pull/29743).
## What changed
- Delegate new context-window installation to
`replace_compacted_history`.
- Reuse its ID assignment, in-memory replacement, world-state baseline,
checkpoint persistence, turn-context persistence, and session-start
bookkeeping.
- Add focused coverage that verifies generated IDs are present in live
history and preserved in the persisted replacement history.
## Testing
- `just test -p codex-core
start_new_context_window_assigns_and_persists_item_ids`
- `just test -p codex-core
new_context_tool_starts_new_window_before_follow_up`
## Why
The `ItemIds` path fills in missing IDs before response items are
persisted and emitted as raw item events. `ResponseItem::AgentMessage`
is part of that same response-item stream, but it was skipped by the
missing-ID repair path, leaving agent messages without stable item IDs
while messages and tool items received generated IDs.
Agent messages recorded through `InterAgentCommunication` also need the
generated ID to survive rollout persistence and resume. Otherwise
clients can observe an `amsg_` ID for the live raw response item, then
see that same persisted agent message lose its item ID after restart.
## What changed
- Assign missing `ResponseItem::AgentMessage` IDs with the `amsg_`
prefix.
- Persist the generated item ID on `InterAgentCommunication` and replay
it back into the reconstructed `ResponseItem::AgentMessage` on resume.
- Keep the persisted ID out of the model-visible inter-agent message
envelope.
- Keep `CompactionTrigger` and `Other` skipped because they do not get
generated item IDs.
- Update session/protocol tests for agent-message ID assignment and
resume preservation.
## Manual Testing
Run the local dev build using `just c --enable item_ids` to ensure this
code is exercised:
https://github.com/openai/codex/blob/322e33512b2d38d38d705e2ef692a8aca50decac/codex-rs/core/src/session/mod.rs#L2713-L2715
In the `.jsonl` file, I saw entries like:
```json
{
"timestamp": "2026-06-24T00:44:03.098Z",
"type": "inter_agent_communication",
"payload": {
"id": "amsg_019ef715-849a-7a50-becc-ce63c6a9c994",
```
## Test plan
- `just test -p codex-core
record_inter_agent_communication_preserves_item_id_in_rollout_and_resume`
- `just test -p codex-core
record_inter_agent_communication_sets_turn_id_in_rollout_and_resume`
- `just test -p codex-protocol
inter_agent_communication_response_input_item_preserves_commentary_phase`
## 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`
## Why
When `Feature::TokenBudget` is enabled, compaction should behave like
`new_context`: start a fresh context window with the standard injected
context, without asking the server to summarize old history and without
carrying prior user or assistant messages into the next model request.
This is still a compaction operation from the client lifecycle
perspective. Manual `/compact` and auto-compaction should keep the same
observable side effects that clients and hooks expect, including compact
hooks and `TurnItem::ContextCompaction`.
## What changed
- Added `compact_token_budget` to run token-budget manual and inline
auto-compaction through a shared compaction lifecycle.
- Split pending `new_context` requests from forced context-window
startup: `take_new_context_window_request()` consumes pending requests,
and `start_new_context_window()` installs a fresh context window.
- Routed token-budget manual `/compact` and inline auto-compaction to
install a fresh context window locally instead of calling server/local
summarization.
- Preserved compact lifecycle side effects for token-budget compaction
by running pre/post compact hooks and emitting `ContextCompaction` item
start/completion events.
- Updated token-budget tests to assert fresh window IDs, absence of
server-side compaction calls, dropped prior transcript messages/tool
output after reset, and compact hook/item lifecycle behavior.
## Testing
- `just test -p codex-core
token_budget_context_uses_new_window_after_compaction`
- `just test -p codex-core token_budget_compaction_runs_compact_hooks`
- `just test -p codex-core
token_budget_mid_turn_auto_compaction_resets_before_active_follow_up`
---------
Co-authored-by: pakrym-oai <pakrym@openai.com>
## Why
This PR keeps the mechanical helper extraction separate from the
behavior change in #29665. The follow-up needs the token-window
accounting from `turn.rs` in another call path, but reviewing that is
much easier when the helper extraction is separate from the semantic
change.
## What
- Adds `session/context_window.rs` with `ContextWindowTokenStatus`.
- Moves the existing auto-compaction token-status calculation out of
`session/turn.rs`.
- Replaces the duplicated inline remaining-token calculation in
`turn.rs` with `tokens_until_compaction()`.
This PR is intended to be behavior-preserving. The
`get_context_remaining` behavior change is stacked separately in #29665.
## Testing
- `just test -p codex-core auto_compact_body_after_prefix`
---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/openai/codex/pull/29664).
* #29665
* __->__ #29664
## Why
With deferred executors, an environment can become ready between two
sampling requests in the same turn. The model-visible environment
update, advertised tools, and eventual tool execution must all describe
the same request-time view.
Otherwise, a request built while only environment B is ready can
advertise a tool without an `environment_id`; if higher-priority
environment A becomes ready before execution, that call could silently
run in A instead.
This PR is stacked on #29527.
## Design
`run_turn` captures one `Arc<StepContext>` at each sampling-request
boundary. That step owns the request's `TurnContext` and environment
snapshot.
- World-state environment updates and tool planning borrow that same
step.
- `ToolCallRuntime` retains the `Arc` while asynchronous tool calls
execute.
- `ToolInvocation` carries the step to handlers; its temporary `turn`
compatibility field is derived from the same object.
- `ToolRouter` does not retain `StepContext`; it only uses it while
constructing the request's tool set.
- With `DeferredExecutor` disabled, step capture keeps using the
environments frozen at turn start.
Simply: every sampling request gets one consistent picture of its
environments, from what the model sees through where its tool calls run.
## What changed
- Build environment-dependent tool specs from the current request's
`StepContext`.
- Use that same step for unified exec, legacy shell, `apply_patch`,
`view_image`, and `request_permissions` execution.
- Hide environment-backed tools, including `request_permissions`, while
no environment is attached.
- Resolve legacy shell paths and metadata from the selected step
environment instead of the stale turn-start environment.
- Capture explicit steps at non-turn-loop boundaries such as compaction,
prompt debug, and startup prewarm.
- Reconcile prompt-debug history from the same step used to build its
tools.
## Follow-up
- Bind yielded code-mode cells to the tool runtime that created them, so
nested calls made after yielding continue to use the originating
request's `StepContext`.
## Test plan
- `just test -p codex-core
deferred_executor_updates_context_and_tools_after_startup`
- `just test -p codex-core
environment_count_controls_environment_backed_tools`
- `just test -p codex-core
build_prompt_input_includes_context_and_user_message`
## Why
Follow-up to #29249 and its [compaction review
thread](https://github.com/openai/codex/pull/29249#discussion_r3455055101).
During a turn, environment readiness can change between sampling
requests. Inline compaction must render the same model-visible
`WorldState` used by the request it follows. Rebuilding that state
during compaction can observe a newer environment, make replacement
history disagree with what the model saw, and suppress the next
environment update.
## What changed
- Make `run_turn` own the current `Arc<WorldState>` and replace it only
between sampling requests.
- Build each state from an explicitly chosen environment snapshot, diff
deferred-executor steps against the turn-owned state, and retain the
latest state in `ContextManager` only for cross-turn and resume
tracking.
- Pass the exact turn-owned state into inline compaction and explicit
new-context-window replacement.
- Carry that state with
`InitialContextInjection::BeforeLastUserMessage`, so replacement context
and its stored baseline cannot come from different snapshots.
- Remove obsolete state-recapture helpers and ambiguous TurnContext-only
WorldState builders.
- Add an integration test that moves an environment from starting to
ready during a paused turn, triggers compaction, and verifies the next
request receives the readiness update exactly once.
## Test plan
- `just test -p codex-core
deferred_executor_compaction_preserves_then_updates_environment_once`
- `just test -p codex-core process_compacted_history`
- `just test -p codex-core mid_turn_continuation_compaction`
- `just test -p codex-core build_initial_context`
- `just test -p codex-core
ignores_session_prefix_messages_when_truncating`
Owen Lin