## What changed
- Retain completed synchronous Guardian reviews as structured records until the async scorer builds its classification input.
- Render and bound review correlation, action, rationale, and full evidence body with the async scorer's transcript truncation marker.
- Extend the Guardian V2 integration test to verify oversized action and rationale content is truncated and the resulting review evidence remains bounded.
GitOrigin-RevId: 0000ba77b810748e34254dd00df4a69f8492e175
## What changed
- Add a `GuardianPolicy` contextual fragment that renders as a standalone
developer message with the `guardian.policy` content kind.
- Use the fragment when rebuilding Guardian context and verify that its content
kind remains attached after history compaction.
GitOrigin-RevId: f7028fb29a48ad2453437f3d3a4405fcab7a2fd7
## What changed
- Add a dedicated contextual fragment for developer instructions that emits the
`generic.developer_instructions` content kind.
- Use the fragment when adding child-specific developer instructions to a
full-history subagent fork, preserving their classification and ensuring they
reach the child exactly once without appearing in the parent request.
## Testing
- Extend full-history subagent coverage to verify the child-only instructions'
annotation, placement, and count.
GitOrigin-RevId: 82589d311535225fed76d500a19458fda72f40f2
## What changed
- Build Responses Lite base instructions through a dedicated context fragment so the developer message carries the `model.base_instructions` content kind.
- Apply provider metadata cleanup after adding the base-instructions message, preserving the existing behavior for non-OpenAI providers.
## Testing
- Extend Responses Lite request coverage to verify the annotation is present for OpenAI requests and omitted for a third-party provider.
GitOrigin-RevId: b0317f92dfb9570860688b49e3a7668da516ee8c
## What changed
- Render omitted image and audio inputs as contextual fragments tagged with
`images.unsupported` and `audio.unsupported` content kinds.
- Normalize message media through annotated content so metadata for surrounding
content remains intact when switching to a model without media support.
## Testing
- Extend history and model-switching tests to verify content-kind annotations
before and after unsupported media is replaced.
GitOrigin-RevId: 4ee6577f8b78bd5a850ee01ea9d4590c20272850
## What changed
- Represent compaction summaries and Guardian-approved actions as typed contextual fragments.
- Inject subagent notifications through the same fragment path.
- Annotate the resulting request items with `compaction.summary`, `guardian.approved_action`, and `multi_agent.subagent_notification` content kinds while preserving their existing roles and text.
## Testing
- Verify the content-kind metadata on compacted summaries, approved actions, and subagent notifications.
GitOrigin-RevId: 01c93e7f08b2dc1c1e85ba69e82bfb5f56e6cca5
## What changed
- Retain bounded evidence from completed synchronous Guardian allow and deny reviews and supply it to subsequent Guardian v2 async classifier samples as trusted developer context.
- Keep review evidence isolated from the conversation transcript, escape and truncate its fields, and ignore failed or incomplete reviews.
- Invalidate retained evidence after conversation history rewrites or new user messages, including authorization changes in a worker's root thread.
## Testing
- Cover approved, denied, malformed, and forged review inputs, plus root rollback and authorization-change scenarios.
GitOrigin-RevId: 27817e1fde9a136de727048c4220d148fcf72f42
## What changed
- Add `additional_developer_instructions` to managed requirements and expose it through `configRequirements/read` as `additionalDeveloperInstructions`, independently of ordinary developer instructions.
- Include the managed instructions in model context, emit explicit replacement or removal messages when requirements change, and preserve the current value across compaction, resume, and agent forks without duplication.
- Reject managed instructions whose rendered context exceeds 10,000 estimated tokens.
## Testing
- Cover requirements layering and API serialization, context updates and removal, size validation, repeated model requests, compaction and resume, rollout migration, and agent forks.
GitOrigin-RevId: bc0b70fb7988944c2f68176dff55f5ed61eb46c8
## Why
Developer messages can contain both inherited agent policy and unrelated context. Full-history forks need to replace the parent policy without dropping the unrelated content that shares its message.
## What changed
- Filter fork-specific developer instructions by content item instead of excluding an entire developer message.
- Remove inherited multi-agent mode instructions before applying the child agent's current mode.
- Preserve unrelated content items and discard developer messages only when filtering leaves them empty.
## Testing
Extend agent-control and subagent notification tests to cover compound compacted messages, multi-agent mode instructions, and proactive-to-explicit mode transitions.
GitOrigin-RevId: 028834e237d8636c13b17a724574bc8eb09a55ba
## What changed
- Add a dedicated developer policy for Guardian reviews of Node REPL browser and computer-use actions.
- Inject the policy once before the first eligible Node REPL approval and retain it when the reviewer session is reused.
- Include Node REPL policy eligibility in the reviewer reuse key so sessions are not reused across incompatible model settings.
- Keep the approval request itself on the generic planned-action format.
## Testing
- Cover first-action injection, reuse after a shell review, repeated Node REPL reviews, and ineligible parent models through the production approval path.
GitOrigin-RevId: bfce190ff8599788aa85e388cc6a959d27fb489c
## Why
`node_repl` screenshots are nested tool results and do not appear in the parent
conversation history, so Guardian v2 transcript image collection could miss
them.
## What changed
- Allow Guardian v2 to enable bounded, thread-scoped `node_repl` image capture
when transcript images are configured.
- Add retained `node_repl` screenshots to review requests when transcript
sources include tool outputs, while deduplicating images and keeping them out
of the parent turn input.
## Testing
- Add an integration test covering screenshot capture without the synchronous
Guardian transcript feature flags and verifying that screenshots stay out of
the parent request.
GitOrigin-RevId: 5f70c5f2e80389aa8b2a286c3b7f9b1104865486
## What changed
- Add model-catalog messages for root and subagent roles, explicit delegation, and delegation hints.
- Resolve role instructions in config, catalog, then bundled-default order, while preserving empty values as an explicit way to suppress fallback text.
- Refresh catalog-provided role and mode instructions when the model changes, and give full-history forks the selected child model's subagent role without retaining the parent's role guidance.
- Keep existing config overrides and reasoning-effort behavior, including proactive delegation for ultra reasoning effort.
## Testing
- Cover message deserialization and preservation through model overrides.
- Cover precedence, empty overrides, model switches, resumed sessions, and full-history subagent forks.
GitOrigin-RevId: 4625cf7c6a5490176adddfaa0fb99100707daea9
## What changed
- Preserve valid image content from completed `node_repl` Code Mode responses alongside text evidence for Guardian reviews.
- Enable multimodal evidence for models that require automatic `node_repl` review, or when both `guardian_enhanced_node_repl_transcripts` and `guardian_node_repl_transcript_images` are enabled.
- Bound retained and rendered evidence, deduplicate images already present in review history, and fall back to text-only evidence when the reviewer lacks image support or prompt capacity.
- Keep review evidence out of the parent turn input.
## Testing
- Cover feature gating, mixed text and image ordering, truncation and eviction, unsupported reviewers, prompt pressure, image detail normalization, and reused review sessions.
GitOrigin-RevId: a3e482402f7b3484401b231dadc662e6e3504fdf
## What changed
- Capture accepted, successful `node_repl` results from Code Mode and include them as bounded, untrusted evidence in Guardian review prompts.
- Enable the enhanced transcript through `guardian_enhanced_node_repl_transcripts` or when the selected model requires automatic Node REPL review.
- Keep this evidence out of the parent model history, exclude encrypted and failed results, and avoid resending admitted evidence when a Guardian session is reused.
- Clear retained evidence and invalidate review sessions when a thread is rolled back.
## Testing
- Add unit coverage for evidence ordering, escaping, truncation, and empty responses.
- Add an integration test covering feature-disabled, feature-enabled, and model-required behavior, including filtering and review-session reuse.
GitOrigin-RevId: edc3dca5d5b88d472a492f35531ec46889a89d72
## What changed
- Add `HostSkillsSnapshot::load_skill_prompts` so the skills extension owns reading and rendering selected host skills.
- Keep explicit invocation telemetry, unreadable-skill warnings, plugin prompt ordering, and suppression of host prompts superseded by provider prompts.
- Remove the legacy prompt injection and fragment implementation from `codex-core-skills`.
## Testing
- Cover prompt truncation without an installed skills extension, skill/plugin ordering, selective provider supersession, unreadable skills, and contextual fragment detection.
GitOrigin-RevId: 9c8b84ad54b90d174abc287ab49cc5a231e9e1aa
## Why
Resumed sessions need the current multi-agent usage instructions when configuration changes or the saved history predates usage-hint tracking.
## What changed
- Store multi-agent usage hints in world state and refresh changed or previously untracked hints before re-emitting the active multi-agent mode.
- Present `wait_agent` polling guidance in the overridable developer instructions only when the tool is enabled, instead of embedding it in the tool schema.
## Testing
- Cover cold resumes, changes to `wait_agent` availability, custom usage hints, message ordering, and tool-schema behavior.
GitOrigin-RevId: a9c6798d5dc2dedc8dadc49e0a80ff50a757ab83
## 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
- 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
- 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
- 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
## 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
## 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 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
- 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
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
## 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
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
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
Environment context is model-visible state, but it is currently
assembled from transient turn values and diffed through
environment-specific paths. That makes initial injection, turn-to-turn
updates, and changes that happen within a turn use different baselines.
This PR introduces the smallest useful model world-state slice:
environments only, with one in-memory baseline and one renderer for full
state and diffs.
## What changed
- Add a typed `WorldState` container whose sections render fragments
relative to an optional previous value. Full rendering uses the same
diff path with no previous state.
- Replace the parallel `EnvironmentContext` representation with an
`EnvironmentsState` section keyed by environment ID and rendered in
deterministic order.
- Preserve the legacy single-environment output while supporting
multiple environments, starting environments, unavailable tombstones,
and changes to persisted turn-context values.
- Store the latest complete `WorldState` on `ContextManager` and use it
for both turn-boundary and mid-turn environment diffs.
- Build initial and post-compaction context from the same world-state
builder, then retain the rendered state as the next baseline.
- Seed the in-memory baseline from the latest `TurnContextItem` when
resuming an existing rollout; the world state itself is not serialized.
- Keep non-world settings updates on their existing path and merge
rendered world-state fragments at the session consumer.
## Known limitation
A legacy `TurnContextItem` only reconstructs the primary environment as
`local`; it cannot faithfully recover a remote-primary environment ID
after resume. Live state uses the exact environment IDs once a complete
baseline is established.
## Test plan
- `just test -p codex-core world_state`
- `just test -p codex-core record_context_updates`
- `just test -p codex-core deferred_executor_`
- `just test -p codex-core build_initial_context`
- `just test -p codex-core rollout_reconstruction`
- `just test -p codex-core
process_compacted_history_reinjects_full_initial_context`
## Why
The token-budget feature reports coarse remaining-context milestones,
but it does not give the model a configurable wrap-up prompt before
automatic compaction. A strict threshold-crossing check can also miss
resumed or reconfigured windows that are already inside the threshold.
## What changed
- Add structured `[features.token_budget]` configuration for an absolute
`reminder_threshold_tokens` and bounded `reminder_message_template`;
`{n_remaining}` is expanded when the reminder is delivered.
- Compute remaining tokens against the next effective auto-compaction
boundary, including scoped `body_after_prefix` accounting and the full
context-window limit.
- Make reminder delivery level-triggered before and after sampling, with
one-shot state owned by `AutoCompactWindow` and re-armed on compaction,
`new_context`, restore, or history replacement.
- Leave the existing initial full-window token-budget context, 25/50/75%
notices, and token-budget tools unchanged.
- Persist the resolved feature configuration in the session config lock
and regenerate the config schema.
## Validation
- `just test -p codex-core token_budget`
- `just test -p codex-core
token_budget_reminder_emits_after_crossing_compaction_threshold`
- `just test -p codex-core auto_compact_window`
- `just test -p codex-core
lock_contains_prompts_and_materializes_features`
- `just test -p codex-features`
- `just test -p codex-config`
## Why
Multi-agent v2 currently carries an explicit-request-only delegation
rule in its static usage hint. That provides a safe default, but it
prevents clients from selecting proactive delegation per turn without
changing static guidance or rewriting prior model context.
This change makes delegation mode a session selection that can be
updated through `turn/start`, while deriving the effective model-visible
mode separately for each turn. Eligible multi-agent v2 turns remain
explicit-request-only unless proactive mode is both selected and
enabled.
## What changed
- Add the experimental `turn/start.multiAgentMode` parameter with
`explicitRequestOnly` and `proactive` values. Omission retains the
loaded session's current optional selection.
- Add the default-off `features.multi_agent_mode` feature gate. Eligible
multi-agent v2 turns use the selected mode when enabled; an unset
selection or disabled gate resolves to `explicitRequestOnly`.
- Treat mode prompting as inapplicable for multi-agent v1 and other
unsupported session configurations, producing no multi-agent mode
developer message rather than rejecting the turn.
- Move the explicit-request-only rule out of the static v2 usage hint
and into a bounded, tagged developer context fragment.
- Emit the effective mode in initial context and only when that
effective mode changes on later turns.
- Persist the effective mode in `TurnContextItem` as the durable
baseline for resume and context-update comparisons.
Historical rollout items are not rewritten. Later mode developer
messages establish the current rule incrementally.
## Not covered
- Initial selection through `thread/start` and selected-mode reporting
from thread lifecycle/settings APIs; those are isolated in the stacked
#28792.
- A TUI control or slash command for selecting the mode.
- Persisting a preferred mode to `config.toml`; selection remains
session/turn scoped.
- Changes to multi-agent concurrency limits, tool availability, or model
catalog capability declarations.
- Rewriting historical rollout prompt items. Cold resume restores the
latest persisted effective mode when available while leaving historical
developer messages intact.
## Verification
- `CARGO_INCREMENTAL=0 just test -p codex-core multi_agent_mode`
- Focused app-server coverage verifies that `turn/start.multiAgentMode`
produces proactive developer instructions for an eligible v2 turn.
## Stack
Followed by #28792, which adds `thread/start` initialization and
lifecycle/settings observability.
Stacked on #28822.
## Summary
- add a host-injectable current-time provider with a built-in system
implementation
- record UTC developer reminders in history immediately before due model
requests
- keep cadence state per session and force a refresh after compaction
This does NOT include the app server client <-> server clock logic. This
PR is only for the reminder message & system clock that will be used in
prod.
## Testing
- `just test -p codex-core varlatency_`
- `just clippy -p codex-core -p codex-app-server -p codex-mcp-server -p
codex-thread-manager-sample`
- `just fmt`
## Stack
Depends on #28746. This PR implements shared rollout-budget accounting
and model-visible reminders using the configuration defined in #28746.
# Description / Main changes to Core:
`AgentControl` will now be the area where "rollout level" features &
accounting will have to live. It is incorrectly named for this
responsibility, but I think it can hold all the necessary shared state &
features (rollout token budget, mutliple thread interruption
responsibilitym etc)
In this PR, we have one "token ledger" that each thread will subtract
from when sampling. The "charge" will occur when response.completed() is
done and the calculation will be done on the responses api usage
carrier. The calculation will weigh sampling and pre-fill tokens as
specified.
Every time the budget crosses the configured reminder threshold, a
developer message is appended before the thread's next request
This remaining budget will _always_ be restated/reminded after a
compaction event.
Expiration and fan-out interruption will be in the stacked follow-up
(and also live in Agent Control).
## Reminders
"You have weighted {session_tokens_left} tokens left in the shared
session token budget."
The first request in each thread context receives the current remainder.
Later reminders are emitted after aggregate weighted usage crosses a
configured interval. If several intervals are crossed before a thread
sends another request, Core inserts one reminder with the latest
remainder.
Compaction response usage is charged before the next context starts. The
next reminder is appended after the compaction summary, leaving the
initial context content stable.
## Tests
Integration coverage verifies:
- weighted output and non-cached input accounting
- initial and periodic reminders
- shared accounting between a root and sub-agent
- post-compaction remainder and message placement
Local checks:
- `just fmt`
- `just test -p codex-core rollout_budget`
- `git diff --check`
The full workspace test suite was not run locally.
Summary\n- Await endpoint recommendation selection while constructing
each authenticated turn, removing the first-turn cache race.\n- Snapshot
and filter endpoint candidates once per turn, then use that same set for
the bounded contextual user fragment, tool exposure, and exact install
validation.\n- Keep recommendation selection ephemeral: do not persist
recommendation state in or gate resumed threads on prior context.\n-
Hide the legacy list tool in endpoint mode and preserve legacy discovery
unchanged when the endpoint is disabled or unavailable.\n- Keep remote
plugin and connector app identities out of model-visible context and
attach them only to Codex-owned elicitation metadata.\n\nStack\n- 3/4,
based on #28400.\n- Endpoint client and cache: #28399.\n- Generalized
suggestion presentation: #28400.\n- Install-schema follow-up:
#28403.\n\nValidation\n- \n- \n- \n- \n- Full : 2,649 passed and 88
environment-dependent tests failed because this sandbox cannot write ,
nest Seatbelt, or locate auxiliary test binaries.
## Why
Multi-agent v2 messages need a consistent, model-visible envelope that
identifies what kind of interaction occurred, who sent it, and which
agent it targets. Previously, encrypted deliveries exposed only
`encrypted_content`, while child completion used the legacy
`<subagent_notification>` shape. That meant the client could not
consistently present `NEW_TASK`, `MESSAGE`, and `FINAL_ANSWER` using the
same format.
This change adds the routing envelope as plaintext while keeping task
and message payloads encrypted. No new Responses API field is required:
an encrypted delivery is represented as an `input_text` header
immediately followed by its existing `encrypted_content` item.
Every envelope now follows this shape:
```text
Message Type: <NEW_TASK | MESSAGE | FINAL_ANSWER>
Task name: <recipient agent path>
Sender: <author agent path>
Payload:
<message payload>
```
## Message types
### `NEW_TASK`
`NEW_TASK` is used when the recipient should begin a new turn, including
an initial `spawn_agent` task and a later `followup_task`.
For a root agent spawning `/root/worker`, the request contains a
plaintext envelope followed by the encrypted task:
```json
{
"type": "agent_message",
"author": "/root",
"recipient": "/root/worker",
"content": [
{
"type": "input_text",
"text": "Message Type: NEW_TASK\nTask name: /root/worker\nSender: /root\nPayload:\n"
},
{
"type": "encrypted_content",
"encrypted_content": "<encrypted task payload>"
}
]
}
```
Conceptually, the model receives:
```text
Message Type: NEW_TASK
Task name: /root/worker
Sender: /root
Payload:
Review the authentication changes and report any regressions.
```
### `MESSAGE`
`MESSAGE` is used for a queued `send_message` delivery. It communicates
with an existing agent without starting a new turn.
For `/root/worker` reporting progress to the root agent, the request
contains:
```json
{
"type": "agent_message",
"author": "/root/worker",
"recipient": "/root",
"content": [
{
"type": "input_text",
"text": "Message Type: MESSAGE\nTask name: /root\nSender: /root/worker\nPayload:\n"
},
{
"type": "encrypted_content",
"encrypted_content": "<encrypted message payload>"
}
]
}
```
Conceptually, the model receives:
```text
Message Type: MESSAGE
Task name: /root
Sender: /root/worker
Payload:
The protocol tests pass; I am checking the resume path now.
```
### `FINAL_ANSWER`
`FINAL_ANSWER` is emitted when a child agent reaches a terminal state
and reports its result to its parent. Completion payloads are already
available locally, so the complete envelope is represented as plaintext
rather than as a plaintext header plus encrypted content.
For `/root/worker` completing work for the root agent, the request
contains:
```json
{
"type": "agent_message",
"author": "/root/worker",
"recipient": "/root",
"content": [
{
"type": "input_text",
"text": "Message Type: FINAL_ANSWER\nTask name: /root\nSender: /root/worker\nPayload:\nNo regressions found."
}
]
}
```
The model-visible form is:
```text
Message Type: FINAL_ANSWER
Task name: /root
Sender: /root/worker
Payload:
No regressions found.
```
Errored, shut down, and missing agents also use `FINAL_ANSWER`, with a
terminal-status description in the payload.
## What changed
- Render `NEW_TASK` or `MESSAGE` in
`InterAgentCommunication::to_model_input_item`, based on whether the
encrypted delivery starts a turn.
- Replace the multi-agent v2 `<subagent_notification>` completion
payload with a model-visible `FINAL_ANSWER` envelope.
- Document `Task name`, `Sender`, and `Payload` consistently in the
multi-agent developer instructions.
- Prevent local-only history projections from treating an encrypted
message's plaintext header as the complete assistant message.
- Preserve rollout-trace interaction edges when an agent message
contains both plaintext and encrypted content.
Legacy multi-agent behavior remains unchanged.
## Verification
- `just test -p codex-protocol`
- `just test -p codex-rollout-trace`
- `just test -p codex-web-search-extension`
- `just test -p codex-core
encrypted_multi_agent_v2_spawn_sends_agent_message_to_child`
- `just test -p codex-core
plaintext_multi_agent_v2_completion_sends_agent_message`
- `just test -p codex-core
multi_agent_v2_followup_task_completion_notifies_parent_on_every_turn`
- `just test -p codex-core
multi_agent_v2_completion_queues_message_for_direct_parent`
## Why
#27198 made the extension-owned `codex_apps` MCP connection the hosted
plugin runtime, but its `mcp/skill` resources still bypassed the skills
extension. App-server could list and read those resources through
generic MCP APIs, but a thread with no selected environment did not
expose them in the model's skills catalog or load their `SKILL.md`
through `$skill`.
Hosted skills should stay remote while using the same typed catalog,
source authority, deduplication, bounded contextual catalog, and
selected-skill prompt injection as host and executor skills. They should
not be downloaded or exposed as ambient filesystem paths.
## What changed
- Add a session-scoped `McpResourceClient` over the replaceable MCP
connection manager so resource list/read calls follow startup and
refresh replacements.
- Add a `BackendSkillProvider` that pages `codex_apps` resources,
accepts bounded and validated `mcp/skill` entries, and reads a selected
skill's `SKILL.md` through the same MCP connection.
- Register the remote provider in app-server and include it in the
skills catalog even when a thread has no selected capability roots or
executor.
- Contribute hosted skill metadata through the bounded
`AvailableSkillsInstructions` developer-context path, exclude remote
entries from per-turn catalog injection, and classify `<skills>`
messages as contextual developer content so rollback can trim and
rebuild them correctly.
## Testing
- Extend the app-server MCP resource integration test with
`environments: []` to exercise two-page discovery, filter a
non-`mcp/skill` resource, verify the escaped developer catalog entry and
user-role `<skill>` fragment containing the fetched `SKILL.md`, and
preserve generic MCP resource reads.
- Add core event-mapping coverage that classifies `<skills>` developer
messages as contextual history.
## Why
The model should be able to see bounded context-window budget metadata
when the `token_budget` feature is enabled. The full-window message is
only injected with full context, while normal turns get a smaller
follow-up only when reported usage first crosses a budget threshold.
## What changed
- Added the `TokenBudget` feature flag.
- Added `<token_budget>` developer fragments for full context-window
metadata and current-window remaining tokens.
- Inserted the threshold message during normal turn handling by
comparing token usage before and after sampling, avoiding persistent
threshold bookkeeping.
- Added core integration coverage for full-context-only metadata and
25/50/75 percent threshold messages.
## Verification
- `just test -p codex-core token_budget`
- `git diff --check`
## Why
Standalone image generation returns image bytes to the model, but the
model also needs the host artifact path to reference the generated file
in follow-up work.
## What changed
- Append the default saved-image path hint alongside the generated image
tool output.
- Reuse the existing core image-generation hint text.
- Pass the thread ID and Codex home directory needed to compute the
artifact path.
- Add app-server and extension coverage for the model-visible hint.
## Validation
- `just fmt`
- `just bazel-lock-check`
- `just test -p codex-app-server
standalone_image_generation_returns_saved_path_hint_to_model`
## Why
`codex-core` currently owns the generic contextual-fragment trait and
several reusable fragment implementations. That makes it harder for
other crates to share the same host-owned model-input abstraction
without depending on all of `codex-core`.
This change extracts the reusable fragment machinery into a small
`codex-context-fragments` crate so future extension and skills work can
depend on the fragment abstraction directly.
## What Changed
- Added the `codex-context-fragments` crate with:
- `ContextualUserFragment`
- `FragmentRegistration` / `FragmentRegistrationProxy`
- additional-context fragment types
- Moved `SkillInstructions` into `codex-core-skills`, since
skill-specific rendering belongs with skills rather than generic core
context machinery.
- Kept `codex-core` re-exporting the fragment types it still uses
internally, so existing call sites keep the same shape.
- Updated Cargo and Bazel workspace metadata for the new crate.
## Verification
- `cargo metadata --locked --format-version 1 --no-deps`
- `just bazel-lock-update`
- `just bazel-lock-check`
## Why
Goal steering is one form of runtime-owned model context, but the old
`<goal_context>` wrapper made the contextual-fragment hiding path
goal-specific. Using a source-labeled internal context fragment gives
core and extensions a shared shape for hidden model steering while
keeping those prompts out of visible turn history.
The change also keeps legacy `<goal_context>` messages recognized as
hidden contextual input so existing stored history does not start
rendering old goal-steering prompts as user-visible turn items.
## What Changed
- Replaces `GoalContext` with `InternalModelContextFragment` plus a
validated `InternalContextSource`.
- Renders goal steering as `<codex_internal_context
source="goal">...</codex_internal_context>`.
- Updates core goal steering and `ext/goal` steering to inject the new
internal-context fragment.
- Updates contextual-fragment, event-mapping, goal, and session tests
for the new wrapper.
## Test Coverage
- Adds coverage for detecting the new internal model context fragment.
- Preserves coverage for hiding legacy `<goal_context>` fragments.
- Verifies invalid internal context sources are rejected and arbitrary
context tags are not hidden.
- Updates goal steering/session assertions to expect the new
`source="goal"` wrapper.
## Summary
Adds experimental `additionalContext` support to `turn/start` and
`turn/steer` so clients can provide ephemeral external context, such as
browser or automation state, without turning that plumbing into a
visible user prompt or triggering user-prompt lifecycle behavior.
## API Shape
The parameter shape is:
```ts
additionalContext?: Record<string, {
value: string
kind: "untrusted" | "application"
}> | null
```
Example:
```json
{
"additionalContext": {
"browser_info": {
"value": "Active tab is CI failures.",
"kind": "untrusted"
},
"automation_info": {
"value": "CI rerun is in progress.",
"kind": "application"
}
}
}
```
The keys are opaque and caller-defined.
## Context Injection
When provided, accepted entries are inserted into model context as
hidden contextual message items, not as visible thread user-message
items.
`kind: "untrusted"` entries are inserted with role `user`:
```text
<external_${key}>${value}</external_${key}>
```
`kind: "application"` entries are inserted with role `developer`:
```text
<${key}>${value}</${key}>
```
Values are not escaped. Each value is truncated to 1k approximate tokens
before wrapping.
For `turn/start`, accepted additional context is inserted before normal
user input. For `turn/steer`, additional context is merged only when the
steer includes non-empty user input; context-only steers still reject as
empty input.
## Dedupe Strategy
`AdditionalContextStore` lives on session state and stores the latest
complete additional-context map.
Each `turn/start` or non-empty `turn/steer` treats its
`additionalContext` as the current complete set of values. Entries are
injected only when the key is new or the exact entry for that key
changed, including `value` or `kind`. After merging, the store is
replaced with the provided map, so omitted keys are removed from the
retained set and can be injected again later if reintroduced.
Omitting `additionalContext`, passing `null`, or passing an empty object
resets the store to empty and injects nothing.
## What Changed
- Threads experimental v2 `additionalContext` through app-server into
core turn start and steer handling.
- Adds separate contextual fragment types for untrusted user-role
context and application developer-role context.
- Uses pending response input items so additional context can be
combined with normal user input without treating it as prompt text.
- Adds integration coverage for start/steer flow, role routing,
dedupe/reset behavior, deletion/re-add behavior, hook-blocked input
behavior, empty context-only steer rejection, external-fragment marker
matching, and truncation.
## What
- Add a small extension capability for injecting model-visible response
items into the active turn
- Have the goal extension inject hidden goal-context steering when
tool-finish accounting reaches `BudgetLimited`
- Cover the extension backend path with an assertion on the injected
steering item
## Why
PR #23696 persists and emits the budget-limited goal update from
tool-finish accounting, but it leaves the model unaware of that
transition. The existing core runtime steers the model to wrap up in
this case; the extension path should do the same through an explicit
host capability.
## Testing
- `just fmt`
- `cargo test -p codex-goal-extension`
- `cargo test -p codex-extension-api`
## Why
Older sessions can contain model-warning records persisted as `user`
messages, including the unified exec process-limit warning, the
`apply_patch`-via-`exec_command` warning, and the model-mismatch
high-risk cyber fallback warning. Those warnings are no longer produced
as conversation history items, but when old sessions compact they should
still be recognized as injected context rather than preserved as real
user turns.
## What changed
- Removed `record_model_warning` and the production paths that emitted
these warning messages into conversation history.
- Added `LegacyUnifiedExecProcessLimitWarning`,
`LegacyApplyPatchExecCommandWarning`, and `LegacyModelMismatchWarning`
contextual fragments that are used only for matching old persisted
messages.
- Registered the legacy fragments with contextual user message detection
so compaction filters them through the existing fragment path.
- Added focused compaction coverage for old warning messages being
dropped during compacted-history processing.
## Testing
- `cargo test -p codex-core warning`
- `just fix -p codex-core`
## Summary
This PR updates the goal continuation prompt to address feedback from
early adopters. There are two primary changes:
1. Goal continuation and budget-limit steering prompts now use hidden
user-context messages instead of hidden developer messages.
2. The goal continuation prompt is refined to improve the model's
ability to fully complete the active goal rather than stop at a smaller
or merely passing subset.
The user-message transition is important for two reasons. First, it
eliminates an issue where older steering messages could be responded to
again after a new turn. Second, it works better with compaction because
user messages are treated differently from developer messages during
compaction.
The prompt refinements make persistence explicit, ground work in current
evidence, encourage `update_plan` for multi-step progress visibility,
and require stronger completion audits before calling `update_goal`. It
also removes the elapsed-time reporting in the prompt; I saw evidence
that this was causing the model to shortcut work as it became nervous
about time.
These changes were tested with evals. Chriss4123 has also been running
independent evals in
[#19910](https://github.com/openai/codex/issues/19910), and many of the
improvements in this PR were suggested by him.
## Verification
- Tested with evals.
- Added and updated focused `codex-core` coverage for hidden goal user
context, continuation and budget-limit request shape, prompt rendering,
and objective delimiter escaping.
Keep extracting memories out of core and moving the write trigger in the
app-server
This is temporary and it should move at the client level as a follow-up
This makes core fully independant from `codex-memories-write`
---------
Co-authored-by: Codex <noreply@openai.com>
## Why
MultiAgentV2 children should not receive an extra model-visible
developer fragment just because they were spawned. The parent/configured
developer instructions should carry through normally, but the dedicated
`<spawned_agent_context>` block is no longer desired.
## What changed
- Removed the `SpawnAgentInstructions` context fragment and its
`<spawned_agent_context>` wrapper.
- Stopped appending spawned-agent instructions in
`codex-rs/core/src/tools/handlers/multi_agents_v2/spawn.rs`.
- Updated subagent notification coverage to assert inherited parent
developer instructions without expecting the spawned-agent wrapper.
## Verification
- `cargo test -p codex-core --test all
spawned_multi_agent_v2_child_inherits_parent_developer_context --
--nocapture`
- `cargo test -p codex-core --test all
skills_toggle_skips_instructions_for_parent_and_spawned_child --
--nocapture`
- `cargo test -p codex-core --test all subagent_notifications --
--nocapture`
felixxia-oai