## What changed
Recognize `content_policy_violation` in HTTP 400 responses and streamed errors as a dedicated, non-retryable error. Preserve the provider's message and available HTTP status, use a fallback message when needed, and report `CodexErrorInfo::InvalidPrompt` to clients.
End the response stream immediately on this error and stop compaction from falling back to the current model after a content policy rejection. Add redacted diagnostic output and a dedicated sampler failure reason.
## Testing
Extend coverage for HTTP and wrapped WebSocket errors, missing or blank provider messages, terminal stream failures with retry headers, and content policy rejections during local and remote compaction on model downshift.
GitOrigin-RevId: 592170ac30c07b0b303a8d5cb15bd35c8f821b55
## Why
HTTP 403 responses with `invalid_workspace_selected` were treated as unexpected status errors, allowing retries and compaction fallback to another model after the server rejected the selected workspace.
## What changed
Recognize the code in `detail.code` or `error.code`, falling back to the `x-error-json` header when the body has no code. Classify these 403 responses as `InvalidWorkspaceSelected` and disable retries and compaction model fallback while preserving the response details and HTTP status. Other 403 responses retain their existing retry behavior.
## Testing
Add coverage for body and header error codes, code precedence, HTTP and WebSocket retry behavior, and local and remote compaction during a model downshift.
GitOrigin-RevId: f44a3bee5ef06e601909839868ab99cea6dd7d03
## Why
Incomplete responses such as `max_output_tokens` were classified as stream errors, allowing retries and compaction model fallback after the response had hit its output limit.
## What changed
Introduce `ResponseIncomplete` errors that preserve the server-provided reason and stop stream processing immediately. Make these errors non-retryable and stop compaction without falling back to the selected model. Record incomplete responses separately in sampler failure metrics.
## Testing
Add regression tests that verify incomplete responses surface a terminal error without retries over SSE and WebSocket, and that compaction stops without retrying or switching models for both local and remote compaction.
GitOrigin-RevId: 6e107d441b9bf03fa47ea47b88eeb94b71a9f729
## Why
Manual, pre-turn, and post-turn compaction previously deferred rebuilding initial context until the next turn. Their saved replacement history could omit refreshed instructions and skill catalogs.
## What changed
- Install initial context during local and remote compaction, before the last real user message or summary, keeping the compaction summary last.
- Persist matching full world-state and turn-context baselines with every replacement instead of retaining only partial extension metadata.
- Build replacement context and recompute token usage for the current model even when the previous model performs compaction. Reuse that captured context for eligible current-model retries.
- Capture manual compaction context centrally and propagate preparation errors to the task runner.
## Testing
Update assertions and snapshots for context ordering, refreshed instructions, resume and fork history, current-model checkpoint baselines, and cloud skill catalog retention across compaction and resume.
GitOrigin-RevId: 8572a76c31c6884a3c580b3bbb350d49af876bd1
## Why
After a model switch, compaction with the previous model could fail after exhausting stream retries without falling back to the selected model.
## What changed
Allow compaction to fall back to the current model for all errors except `TurnAborted`, `Interrupted`, and `SessionBudgetExceeded`.
## Testing
Add a regression test that exhausts the previous model's compaction stream retries, then verifies that fallback compaction and turn sampling use the selected model.
GitOrigin-RevId: 9c9b7ccbb206d19f1ae750a32636fc9acaacfb2b
## Why
Remote compaction already uses the normal Responses API, leaving the legacy `/responses/compact` runner unused.
## What changed
- Remove the legacy runner, endpoint client, request types, analytics variant, and obsolete test helpers and snapshots.
- Move tool-output trimming and its metadata tests into `compact_remote_history` for reuse by remote compaction v2.
- Consolidate retained-history filtering in the v2 implementation and remove redundant `RemoteCompactionV2` settings from tests.
## Testing
Extend the retained-history unit test to explicitly check that hook prompts survive compaction.
GitOrigin-RevId: 999bb1391aa22c3c281d6a96f98817d6c9e46ed9
## What changed
- Wrap `CodexErrorDetails` and an optional retry delay in `CodexErr`, allowing any mapped error to preserve server-provided retry timing.
- Generate the payload-free `CodexErrKind` classification alongside the error details and reuse it for analytics.
- Update error handling sites to inspect `CodexErr::details()` while preserving existing display, debug, protocol mapping, and retryability behavior.
## Testing
- Add coverage for legacy debug formatting, error-specific retryability, and retry-delay propagation through API error mapping.
GitOrigin-RevId: d3ab8a305f2a2ee21d0c0a8c8c388b06dda9c59a
## Why
Compacting a resumed conversation can fail when its previous model is no longer
available. Some model-specific failures, such as a model-not-found response, are
not represented as invalid requests and therefore did not trigger the existing
fallback to the currently selected model.
## What changed
- Share a retry predicate between both remote compaction implementations.
- Fall back to the current model for invalid requests, unexpected statuses,
context-window and usage-limit errors, server failures, and exhausted retries.
## Testing
Add an integration test that resumes a conversation whose previous model returns
model-not-found and verifies that compaction and the next turn use the renamed
model.
GitOrigin-RevId: c3857beae2ce79b50589deb13c2e59710ce14725
## Why
Pre-sampling compaction intentionally uses the previous turn's model
when the compaction compatibility hash changes or when switching to a
model with a smaller context window. This keeps compaction aligned with
the settings that produced the history, but it can block the next turn
when a resumed ChatGPT thread still references a model slug that has
since been retired. The Codex backend rejects that compaction request
before the user's currently selected model gets a chance to sample.
This PR lets those threads recover without changing previous-model
compaction behavior for API-key authentication or custom providers. It
is stacked on #31316, which is a behavior-preserving extraction of the
individual remote compaction attempts; this PR contains the fallback
behavior.
## What changed
- For automatic previous-model compaction, capture the selected model's
request context when using ChatGPT authentication with the OpenAI
provider and the selected model differs from the previous model.
- If the previous-model attempt returns an `InvalidRequest`, retry
compaction once with the selected model for both `/responses/compact`
and Responses Compaction V2.
- Complete history processing, lifecycle events, and token accounting
with the context of the model that successfully compacted the thread.
- If the fallback also fails, return the original previous-model error
so the retry does not change the user-visible failure.
- Record fallback attempts with reason, implementation, and outcome
telemetry.
- Leave API-key authentication, custom providers, same-model turns, and
non-`InvalidRequest` failures on their existing paths.
## Testing
- `just test -p codex-core -E 'test(pre_sampling_compact) |
test(model_unavailable_error)'` (10 tests)
- Added integration coverage for a resumed thread whose model was
renamed, a model downshift using Responses Compaction V2, and API-key
authentication with a custom provider.
Charlie Marsh