## What changed
- Add the disabled-by-default `image_resize_notice` feature.
- When enabled, append a developer message after resized images from user
messages or tool outputs. The notice identifies each image and reports its
original and prepared dimensions.
- Persist notices with new history while avoiding backfilled notices for images
processed when a session is resumed.
## Testing
- Cover notice placement, image numbering, failed images, user and tool image
sources, and resumed-session replay.
GitOrigin-RevId: 11dd808b3ad47eac35e9e2f4a4370f85d0122770
## What changed
- Build filesystem and permission context from the primary turn environment's permission profile, working directory, and workspace roots, falling back to the thread context when no primary environment is available.
- Build capability-discovery sandbox contexts from each environment's permission profile and treat discovery as restricted when any selected environment has restricted filesystem access.
## Testing
- Add regression tests covering environment-specific capability discovery and permission context updates.
GitOrigin-RevId: 6bbbd9b88aafa5e6583971ce4e427fc7557f2d93
## What changed
- Remove the hidden `PairProgramming` and `Execute` variants from `ModeKind`.
- Delete their unused prompt templates and simplify mode handling to cover only `Default` and `Plan`.
GitOrigin-RevId: 8d24e3f562a09e3071b2decae275d2b3871a1e9c
## What changed
- Add a `features.token_budget.mode` setting with `thread` and `name` values.
- Default context-window metadata to the thread ID while allowing configurations to retain the agent name.
- Preserve the selected identity mode when applying model token-budget defaults and replaying locked configuration.
## Testing
- Cover configuration parsing and both identity formats in token-budget context messages.
GitOrigin-RevId: f6e6d2c49e09e70c0352e803bb65784ef77e5bee
## What changed
- Replace the thread ID in `<context_window>` metadata with the session's canonical agent path.
- Default sessions without an agent path to `/root`.
- Verify that root sessions emit `/root` and subagent sessions emit their own path, such as `/root/worker`.
GitOrigin-RevId: bcf057842ed31f93d554b7de063b6c03403a2594
## What changed
- Track approved command prefixes separately from the stable permissions
instructions in world-state snapshots.
- Emit only newly approved prefixes after an exec-policy amendment instead of
appending the full permissions block again.
- Preserve prefix updates when full permissions instructions are disabled and
remain compatible with legacy world-state snapshots.
## Testing
- Cover incremental prefix additions, removals, legacy snapshots, history
rollback, and approval flows with permissions instructions enabled or disabled.
GitOrigin-RevId: e6f68c6a91be82750e70e28456f2b7c58607fbd8
## What changed
Replace the type-erased `FragmentRegistration` trait and proxy objects with a
static list of `matches_text` function pointers. Remove the registration types
and their re-exports while preserving the existing contextual fragment matchers.
GitOrigin-RevId: 4e5a296b278984c6e783a67f48fa4bb37646946b
## What changed
- Add optional `realtimeStartInstructions` and `realtimeEndInstructions` fields to `thread/realtime/start`.
- Apply the instructions when Codex enters and leaves realtime mode, while preserving the existing defaults when either field is omitted.
- Limit each field to 8,192 estimated tokens.
## Testing
- Cover custom entry and exit instructions across realtime state transitions.
- Cover token-limit validation for both fields.
GitOrigin-RevId: b9cfa1ff22e084d8a6b2ed56bd27d95ffdd6b6bd
## What changed
- Make the skills extension own the catalog prompt templates and rendering path.
- Remove the duplicate core fallback that injected available skills into initial context.
- Update core integration tests to install the skills extension explicitly when they expect model-visible skill context.
GitOrigin-RevId: bbe6b15c4e776a09c98b7f4166426fe4e58434ba
## What changed
- Add optional `default` and `plan` collaboration-mode messages to model catalog metadata.
- Prefer the active mode's catalog message, including an explicit empty value, while falling back to the existing developer instructions when the catalog variant is absent.
- Track the model in collaboration-mode world state so mode and model changes append the appropriate instructions, and clear prior instructions when no current message exists.
- Preserve catalog collaboration messages when instruction overrides remove other model instruction fields.
## Testing
- Cover catalog deserialization, variant selection, fallback and empty-message behavior, legacy snapshot migration, mode changes, and model changes.
GitOrigin-RevId: d4c6c0028423bc50b0e8175e55586f3e7bc1c3a8
## Why
The `<current_date>` in environment context could diverge from the clock used by current-time features, especially when a host provides an external clock.
## What changed
- Read the current time from the session's time provider whenever world state is built, and render its local date in environment context.
- Use each session's own thread ID for clock reads, including guardian sessions.
- Propagate clock-read failures through turn error events and stop before model inference.
## Testing
- Cover date updates across turns and app-server requests.
- Verify guardian clock reads use the corresponding root or guardian thread ID and do not run during prewarm.
- Verify clock failures emit an error without sending an inference request.
GitOrigin-RevId: bb7f32ccc0229b7bc6f14d7356db00bcce78066d
## Why
When a turn uses multiple environments, the environment context lists each one but did not identify which environment is primary.
## What changed
- Add a `primary` attribute to each environment in multi-environment model context.
- Persist primary selection in world-state snapshots and emit updates when the primary environment changes.
- Restate environments when transitioning between single- and multi-environment context, while preserving the existing single-environment format.
## Testing
- Cover primary-environment changes, single/multi-environment transitions, legacy snapshot compatibility, and deferred-executor promotion after environment startup.
GitOrigin-RevId: 73a1d794a227edef6e9b7844e7f947b7f598dc80
## What changed
- Preserve `encrypted_function_args` on function calls so an empty list can mark plaintext collaboration arguments across request replay.
- Deliver `spawn_agent`, `send_message`, and `followup_task` payloads as structured plaintext agent messages when that marker is present; retain encrypted delivery otherwise.
- Redact plaintext collaboration arguments from tool and communication logs, and omit the metadata when sending requests to non-OpenAI providers.
## Testing
- Cover serialization of empty encrypted-argument metadata and plaintext versus encrypted subagent message delivery.
- Verify plaintext tool arguments are redacted and provider-specific metadata is removed from non-OpenAI requests.
GitOrigin-RevId: 64db98ff0b61a3af2f04ed609292363f2e2362a8
## What changed
- Insert the `host_skills` world-state section before the permissions section
when permissions are present.
- Verify that skill metadata appears before `<permissions instructions>` in the
rendered developer message.
GitOrigin-RevId: e9fc62f498c384e841fc34ef679850557645f989
## What changed
- Add token-budget settings to model catalog messages and apply them when the
feature is enabled without explicit token-budget configuration.
- Keep explicit user settings authoritative, reject invalid catalog defaults,
and preserve resolved defaults in exported config locks.
- Manage context-window guidance through world state so it updates once when
the active model changes while retaining prior conversation history.
## Testing
- Cover catalog defaults, explicit overrides, disabled features, invalid
values, config-lock replay, and model switching.
GitOrigin-RevId: 54544fefaa14b09f5ef5bad9967a13c52b87b0fe
## What changed
- Add model and personality sections to the persisted world-state snapshot.
- Generate model-switch and personality instructions through world-state diffs, including when prior state must be inferred during replay.
- Keep those instruction fragments in standalone developer messages instead of merging them with adjacent context updates.
## Testing
- Cover initial, unchanged, and changed model and personality states.
- Verify that model changes are recorded in rollout world-state items.
GitOrigin-RevId: 497e29cf38cac08e992e546df900f6f8b01120f9
## What changed
- Add the disabled-by-default `deferred_tool_world_state` feature, which exposes deferred tool namespaces and their descriptions to the model in a `<tools>` world-state section.
- Emit added and removed namespace updates as tool availability changes, bound the rendered context size, and persist nonempty state across thread resumes.
- Omit empty tool state while retaining deferred tool discovery through `tool_search`.
## Testing
- Cover initial, unchanged, removed, recovered, empty, and resumed namespace state, along with description truncation and rendered-size limits.
GitOrigin-RevId: 867e599666dc3569eb0789ba78aaa40254253a6f
## Why
Multi-agent mode instructions are durable model context and need to survive
history changes without re-emitting unrelated setup hints.
## What changed
- Add a `multi_agent_mode` world-state section that diffs, retains, and restores
the effective mode instructions.
- Persist mode changes in world-state snapshots while keeping the legacy
`TurnContextItem.multi_agent_mode` field for reading older rollouts.
- Keep initial mode instructions after the root-agent usage hint so the active
mode takes precedence, and bound custom mode text before snapshotting it.
## Testing
- Add snapshot coverage for mode transitions, retained history, and custom-text
truncation.
- Verify live mode changes preserve instruction ordering, avoid duplicating the
usage hint, and record both modes in world state.
GitOrigin-RevId: 96b9964d6e5299b07a011c559b68e3d948a49226
## Why
Default read-only protections for project metadata should apply when paths such
as `.git`, `.agents`, and `.codex` exist, without causing sandbox setup to
materialize missing paths as ACL targets.
## What changed
- Add an optional `missing_path_behavior` to filesystem sandbox entries and
mark default project-metadata protections with `skip`.
- Preserve the behavior through permission transforms and exec/MCP protocol
serialization while keeping existing path wire variants stable.
- Ignore skip-missing entries when projecting configuration or Windows sandbox
overrides, while retaining explicit metadata carveouts.
## Testing
- Cover protocol round trips for path and special-path entries.
- Verify default metadata protections and Windows explicit carveout handling.
GitOrigin-RevId: 6df13dadacdd131c44aab9f15a967c81051355c1
## What changed
- Add model-catalog approval message variants for `never` and `unless_trusted`.
- Select the catalog message that matches the active approval policy, while retaining the existing built-in text when that variant is absent.
- Treat an explicitly empty variant as an instruction to suppress the built-in approval text, consistent with `on_request` messages.
## Testing
- Cover variant selection, fallback and empty-message behavior, catalog deserialization, and the initial permissions message sent to the model.
GitOrigin-RevId: a0f8d41a08645f39b80093be53f200eeee18ca25
## What changed
- Tell the model that generated images are already displayed to the user and should not be repeated as Markdown images or file links.
- Keep generated-image artifact paths and output hints owned by the image generation extension.
- Centralize the availability check for the image generation tool across feature, provider, namespace-tool, model modality, and authentication requirements.
## Testing
- Verify artifact paths sanitize session and call identifiers.
- Verify the model-facing output hint reports that the generated image is already displayed.
GitOrigin-RevId: 6c865b6a96d6a71bb2c33246d1518a00e7c8b840
## What changed
- Model permission instructions as a world-state section keyed by a stable hash of their rendered developer message.
- Re-emit permission context when its model-visible contents change or the retained fragment is missing, while avoiding duplicates when matching instructions already exist in history, including bundled developer messages.
- Normalize CRLF line endings when hashing world-state fragments so equivalent content produces the same snapshot.
## Testing
- Add snapshot coverage for unchanged, changed, absent, and unknown permission state.
- Cover bundled retained permissions and restored world-state baselines during rollout reconstruction.
GitOrigin-RevId: 7d8d212460c1690ca617859f66dcd825987f1e23
## What changed
- Represent whether realtime is active as a persisted world-state section.
- Emit start and end instructions from world-state transitions, including when
reconstructing context after resume.
- Retain existing realtime start fragments and avoid emitting another start when
custom instructions change while realtime remains active.
## Testing
- Add snapshot coverage for absent, unknown, active, and inactive realtime state
transitions.
- Cover realtime start and end updates plus resuming with changed custom start
instructions.
GitOrigin-RevId: ec670b8132b0f1c9317738bfdeb272069927d91d
## What changed
- Model collaboration mode as a world-state section whose persisted snapshot is
the active mode.
- Emit collaboration instructions when the mode changes, while ignoring
instruction text changes within the same mode.
- Restore persisted collaboration instructions when they are missing from
retained history, including after a fork.
## Testing
- Add snapshot coverage for initial, unchanged, changed, and unknown mode state.
- Cover retained-history restoration and same-mode instruction changes.
GitOrigin-RevId: ffd1683499f09acef6516b0bfcb5bcb4d3f28df4
## What changed
- Treat an empty custom `multi_agent_mode_hint_text` as having no instructions to emit.
- Avoid adding an empty multi-agent mode message both on the initial turn and when the configured hint changes after resuming a session.
## Testing
- Update the empty-hint integration test to assert that no mode message is sent.
- Add resume coverage that verifies changing a custom hint to an empty string emits no update.
GitOrigin-RevId: 8033292115936fac2cf22f85141278595804ee61
## What changed
- Add `<source>transcript_tail_flush</source>` to realtime delegation payloads
emitted when a session flushes its remaining transcript tail.
- Keep explicit realtime handoff payloads unchanged.
- Render both delegation variants through a shared contextual user fragment.
## Testing
- Update realtime conversation tests to cover tagged transcript-tail flushes and
preserve the existing handoff format and XML escaping behavior.
GitOrigin-RevId: 33f70d16cf45b3af8068565c4cf2b1785be3f1d9
## Why
With deferred execution enabled, rebuilding a step context from the latest
thread environment snapshot could apply a settings update to a turn that was
already in progress.
## What changed
- Preserve each turn's captured environment selections when creating later
step contexts.
- Refresh only the readiness of environments that were already starting, while
retaining their original selection order.
- Apply updated environment selections to the next turn.
## Testing
Add coverage for changing the selected workspace while a turn is paused,
verifying that the active turn keeps its original working directory and the
next turn uses the new one.
GitOrigin-RevId: c6f4388c843384ef045b7abdbc303dcfca11d230
## Why
An execution environment marked `starting` is not yet usable, but unrelated work can continue while it becomes ready.
## What changed
- Add developer guidance that explains execution-environment isolation and the resources that become available after startup.
- Tell the model to wait only when the current task needs the starting environment.
- Retain the guidance across world-state updates without duplicating it in request history.
## Testing
- Cover world-state transitions, history retention, rollback handling, and deferred-environment request deduplication.
GitOrigin-RevId: f12f9204d4cbddce50a70eb0998beb6b66cd2fa9
## What changed
- Represent built-in filesystem policy entries with the same `Path` and
`Special` variants used by other entries.
- Remove generated-default filtering from Windows sandbox policy resolution and
simplify elevated deny-write handling to rely on direct-runtime enforcement
and the legacy policy projection.
- Update protocol conversions, policy transforms, and profile expectations for
the reduced filesystem path model.
GitOrigin-RevId: a65793e6855a03d52a575e82cb3d4b9b2e32db5c
## Why
Windows firewall enforcement is tied to the logon-user sandbox identities. Proxy-enforced commands therefore need the elevated backend even when the configured sandbox mode is the default restricted-token mode.
## What changed
- Select the elevated Windows sandbox backend whenever a command uses the managed network proxy.
- Remove configuration and startup checks that required users or managed requirements to select the elevated sandbox explicitly.
- Start and expose managed network proxy state consistently on Windows.
## Testing
- Verify that proxy enforcement selects the elevated backend for the restricted-token sandbox mode.
GitOrigin-RevId: e01ac052587721c468a8fbcf4e2c7c5a185a3e05
## Why
Elevated Windows sandbox setup could turn the built-in read-only protections
for workspace metadata into deny-write paths, creating metadata directories
that did not already exist.
## What changed
- Track whether filesystem permission entries come from a built-in profile or
were explicitly configured.
- Exclude generated metadata defaults from direct Windows deny-write overrides
while continuing to enforce explicit read-only carveouts for the same paths.
- Preserve the distinction while materializing and normalizing permission
paths, without exposing generated defaults as user configuration.
## Testing
Added Windows coverage confirming that elevated sandbox setup leaves missing
workspace metadata absent and still produces overrides for explicit metadata
carveouts.
GitOrigin-RevId: 701bcb229f631b18ab5ced22f3edf6f303d932f3
## What changed
- Add a shared test helper that renders before-and-after section states alongside the resulting role and content.
- Convert the agents, environment, apps, and plugins world-state tests to snapshot tables covering absent, unknown, unchanged, changed, and removed states.
GitOrigin-RevId: 03372a5f925d2019f37bf5a5a2f060261899026c
## Why
Token-budget sessions need a final opportunity to preserve important state before the current context is compacted.
## What changed
- When `auto_compact_fallback_prompt` is configured, reserve `auto_compact_fallback_buffer_tokens` beyond the base auto-compaction limit.
- At the base limit, inject the fallback prompt once as a developer message while keeping the normal tool surface available. Continue reporting zero base-window tokens during this reserve.
- Roll over when the reserve or full model context is exhausted, and skip the fallback when a new context was already requested.
## Testing
Added coverage for using the fallback reserve, rolling over after it is exhausted, and bypassing the fallback for an explicit `new_context` request.
GitOrigin-RevId: 32983ecadc5cb4927e15ecd7b1e896cb52a9ad3b
## Why
Special filesystem subpaths can contain relative or foreign-platform path
spellings. Treating this wire text as a host-native path can reinterpret it.
## What changed
- Store special filesystem subpaths as strings in the core permissions model.
- Represent app-server subpaths as `LegacyAppPathString` and convert them at
the protocol boundary without changing their spelling.
- Add `LegacyAppPathString::from_string` for callers that already own legacy
app-server path text.
GitOrigin-RevId: 2214f03aa997fd0e6eb2ab60d425304bb4bd6132
## 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
## What changed
- Limit `request_plugin_install` guidance to explicitly requested plugins after tool search has been exhausted.
- Exclude adjacent capabilities, broad recommendations, and plugins that only seem potentially useful.
- Clarify that `plugin_id` is the parenthesized ID from `<recommended_plugins>` and prohibit parallel tool calls.
- Keep the recommendation context focused on listing available plugins while the tool specification owns the installation criteria.
## Testing
- Update tool specification tests to verify the stricter eligibility and serialization guidance.
GitOrigin-RevId: 6ebfdd864a76316ab59a0624dc4d7d3abda39a98
## 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
After switching from proactive delegation to explicit-request-only mode, an
earlier proactive instruction can remain in the conversation context. The new
mode must clearly supersede that instruction.
## What changed
Update the explicit-request-only developer message to cancel earlier proactive
delegation instructions before requiring delegation to be explicitly requested
by the user, `AGENTS.md`, or a skill.
## Testing
Update the multi-agent mode integration test expectation for the explicit-mode
instruction emitted after a cold resume.
GitOrigin-RevId: 0a6d18f38ef82d29cf4f3bfcfd4ac84738a39598
## 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
## 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`
## 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
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.
## 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
## Why
World State restores its structured snapshot on resume so unchanged
sections do not have to be rendered again. That is safe only when the
model-visible fragment represented by the snapshot is still present in
retained history.
For selected executor skills, the failing selected-capability scenario
exposed this state:
```text
persisted World State: selected skill catalog is known
retained model history: selected skill catalog message is missing
next diff: unchanged, so emit nothing
```
The model resumes without being told about the selected skill catalog.
## What changed
World State contributions may now optionally describe the concrete
model-visible fragment that must remain in retained history.
When a persisted snapshot is present:
```text
matching retained fragment exists -> trust snapshot, emit nothing
matching retained fragment missing -> treat section as absent, render current state once
```
The skills extension uses this for non-empty selected-environment
catalogs by matching its exact rendered catalog body. Empty or hidden
catalogs do not require a fragment.
## Scope
This does not clear or rebuild the whole World State baseline. It does
not change skill discovery, cache invalidation, environment
availability, or MCP runtime behavior. It only keeps a persisted section
snapshot and its retained model context consistent across resume/history
reconstruction.
## Coverage
A focused World State regression test verifies both sides:
- a missing retained fragment is rendered again
- a matching retained fragment avoids duplicate injection
## Why
#29856 already owns the durable thread intent and exact environment
binding. This PR adds only the small missing extension boundary: an
extension can contribute one named World State section, while core still
owns persistence, diffing, and model-visible fragment types.
This lets skills stay in the skills extension instead of moving their
runtime into core.
## Shape
```text
extension-owned state
|
| contribute section id + JSON snapshot + renderer
v
core World State
|
| compare with the previous snapshot
v
no message, or one incremental model-visible update
```
The extension API is deliberately small:
```rust
fn contribute_world_state(...) -> Vec<WorldStateSectionContribution>
```
Core adapts the rendered result to `ContextualUserFragment`, records the
snapshot, and keeps the existing compaction/resume behavior.
## What changes
- Adds extension-owned World State section contributions.
- Calls those contributors from the existing per-step World State
builder.
- Restores durable selected capability roots into extension thread state
on resume.
- Keeps the actual model-context fragment and rollout machinery in core.
## What does not change
- No skill or MCP implementation moves out of its extension.
- No new file watcher, generation, or RPC.
- No generic migration of existing World State sections.
- No change to the stable environment-ID assumption from #29856.
## Example
```text
step 1 snapshot: skills = []
step 2 snapshot: skills = [executor-demo:deploy]
core asks the skills extension to render only that change.
```
## Stack
1. **This PR:** let extensions contribute World State sections.
2. Project executor skills through the skills extension.
3. 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
Older rollouts can retain model-visible context for a WorldState section
without having a persisted snapshot for that section. Treating the
missing snapshot as definitely absent can duplicate old context or fail
to tell the model that it was replaced or removed.
This provides a generic migration path for sections moving into
WorldState, beginning with AGENTS.md.
Builds on #29810.
## What changed
- distinguish section state that is absent, known from a persisted
snapshot, or unknown because matching legacy context remains in history
- let WorldState sections identify their own legacy fragments while
`ContextManager` owns history reconciliation and baseline persistence
- make AGENTS.md emit one conservative replacement or removal update for
legacy history, then deduplicate from the newly persisted baseline
- preserve existing environment rendering when persisted section data is
missing or malformed
## Testing
- `just test -p codex-core world_state`
- `just test -p codex-core
cold_resume_invalidates_deleted_legacy_agents_md_once -- --exact`
## 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.
Curtis 'Fjord' Hawthorne