## Why
Guardian reviews need the original user instructions even when compaction or
transcript selection removes them from the active conversation window.
## What changed
- Capture complete user messages in host-owned retained context and include them
as ordered authorization evidence alongside verified answers.
- Omit oversized instructions atomically and emit an explicit incomplete-evidence
notice instead of exposing a potentially misleading partial permission.
- Mark user messages inherited by forked agents so they remain model-visible
without becoming child-local authorization.
## Testing
- Cover retained instructions across compaction, resume, rollback, and agent
forks, including oversized evidence and legacy context behavior.
GitOrigin-RevId: 97122509d818c90d2f87c6a1b29c99c05ad0316e
## Why
Guardian can reuse an opaque parent compaction only when the checkpoint's
recorded producer hash matches the scoring model. Missing or incompatible
provenance must not allow an asynchronous score or cached approval to omit
compacted context.
## What changed
- Record the producing model's compatibility hash on compaction history items
and expose the latest checkpoint hash through conversation snapshots.
- In thread-owned context mode, fail closed and require synchronous review when
checkpoint reuse is enabled but the latest checkpoint is incompatible or has
unknown provenance.
- Reject incompatible checkpoints in the sampler while preserving the legacy
context behavior.
## Testing
Add coverage for local, remote, resumed, compacted, and rolled-back histories,
including matching, mismatched, missing, and empty compatibility hashes.
GitOrigin-RevId: 1ce959cb276edc602fd7dfa442133c7fe5e53857
## Why
Compaction replaces the model history window, but host-verified user answers may
still be needed for the rest of the owning thread.
## What changed
- Add bounded, model-invisible retained context for verified
`request_user_input` answers.
- Persist retained context in rollout events and compaction checkpoints, and
restore it when a thread resumes.
- Remove answers when their source turns are rolled back, and prevent
parent-local answers from being inherited by child forks.
## Testing
Add lifecycle coverage for deduplication and size limits, compaction and resume,
rollback, rollout migration, and child forks.
GitOrigin-RevId: c32900d3e8120a9899b71f0576683acd67a4b898
## Why
Context compaction can replace original conversation items that Guardian still needs to review approval-sensitive actions.
## What changed
- Retain a bounded, chronological review history independently of the model's compacted history.
- Keep separate limits for user messages and other transcript items so tool traffic cannot evict user instructions.
- Use the retained evidence for synchronous and asynchronous Guardian transcripts, while resetting it after rollback or history reconstruction.
## Testing
- Cover retention through compaction and eviction, reset behavior after rollback, independent size limits, and asynchronous transcript construction.
GitOrigin-RevId: c5851e992820504fc18de8cfec7f6f9f1b69f316
## Why
Compaction and host-injected context can rewrite the model-visible conversation
without changing what the user authorized. Treating those updates as authorization
changes prevents Guardian from reusing an otherwise valid review.
## What changed
- Track a host-owned user-message revision separately from the conversation history
generation.
- Advance the revision for genuine user messages and history resets, while preserving
it across compaction and internal context injection.
- Use message content-kind metadata to distinguish host context from user input,
conservatively treating unknown or incomplete metadata as user authorization.
## Testing
Added coverage that cached Guardian authorization survives compaction and internal
context, but is invalidated by user input and rollback.
GitOrigin-RevId: c7960fa182d1686042c23764d2abc58acbc4b882
## 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 an extension API for spawning host-owned internal sessions and a
`ThreadReadyInput` lifecycle callback that runs after thread registration.
- Add Guardian reviewer session scaffolding that records the parent thread and
effective model, plus the under-development `guardian_ext` feature flag.
- Start internal sessions with fresh history while preserving parent lineage,
shared session controls, and internal-thread visibility rules.
- Scope internal-session prompt cache keys to their source and parent thread,
and expose `guardian` as an internal session source.
## Testing
- Cover internal-session spawning, parent metadata, history isolation, prompt
cache keys, and extension spawner argument forwarding.
GitOrigin-RevId: 682dae80397d62bb36247796b447042e760ca364
## What changed
- Pass metrics bound to the active turn's model to approval-review contributors.
- Add counter support to `ExtensionMetrics` while preserving host session attribution.
- Record Guardian v2 tool-call score lag and count stale-score fallbacks with the `score_lag` reason.
## Testing
- Cover counter forwarding and session metadata tags.
- Verify Guardian v2 metric samples for current and stale scores.
GitOrigin-RevId: 0ec34736d29d2e37ed217a27e773b4f6230ae38a
## What changed
- Add a shared, read-only `ConversationHistorySnapshot` capability to the extension API.
- Include the snapshot in `ToolStartInput`, preserving conversation order while excluding contextual user messages.
- Avoid acquiring a history snapshot when no tool lifecycle contributors are registered.
## Testing
- Verify snapshots share existing response items, remain stable as history changes, and filter contextual user messages.
- Verify tool-start callbacks receive the history available for successive tool calls.
GitOrigin-RevId: 822cae33781dd876ea628f104be08d8a449a4900
## What changed
- Add an optional `ExtensionMetrics` capability to thread, turn-input, and world-state contributors, backed by session telemetry in the host.
- Record skill counts, omissions, and truncated description characters for extension-rendered catalogs, tagged by the catalog surface.
- Preserve host session attribution on extension metrics, including the effective model for each turn, and prevent extension tags from overriding host metadata.
- Avoid duplicate host-catalog samples by recording world-state metrics only when the section is published or changes.
## Testing
- Cover metric values and surface tags, session metadata preservation, turn-level model changes, and host world-state publication behavior.
GitOrigin-RevId: 9059e521943a8f81df25a38b03692eddbc1d990d
## Why
Extension warnings need a stable thread target even when they are emitted outside an active turn.
## What changed
- Add `ExtensionWarning` and a dedicated `ExtensionEventSink::emit_warning` path with an explicit thread ID and optional turn ID.
- Deliver extension warnings as thread-scoped app-server `warning` notifications, preserving listener ordering and waiting briefly for a subscriber when no listener is active.
- Move skills warnings to the new path, limiting provider catalog warnings to four messages of 256 bytes each.
## Testing
- Cover warning routing, ordering, UTF-8-safe truncation, subscriber fallback, and invalid thread IDs.
- Verify skills warning bounds and app-server delivery of executor catalog budget warnings.
GitOrigin-RevId: 4dcb1ba7f17c0edb1a9d548f9568e0c734bffc15
## 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
Extensions can already expose typed contributions and receive host
capabilities such as `AgentSpawner`, but they do not have a typed way to
send protocol events back through the host. Extensions that need to
surface progress or status should not have to own persistence, ordering,
transport fanout, or logging decisions themselves.
## What
- Add `ExtensionEventSink`, a host-provided fire-and-forget sink for
`codex_protocol::protocol::Event`.
- Add `NoopExtensionEventSink` so hosts that do not expose extension
event emission keep the existing empty-registry behavior.
- Store the sink on `ExtensionRegistryBuilder` / `ExtensionRegistry`,
with `with_event_sink(...)` and `event_sink()` accessors, and re-export
the new capability from `codex-extension-api`.
## Testing
- Not run locally; PR metadata/body update only.
Part 1 of guardian as extension. This bind all the logic to spawn
another agent from an extension and it adds `ThreadId` in the start
thread collaborator
felixxia-oai