- Retain `supported_reasoning_levels` as an empty array instead of deleting the key when no reasoning levels are supported or compatible.
- Continue deleting `default_reasoning_level` when reasoning levels are empty.
- Add `gpt-6-astra` model specifications and capabilities to registry models.
- Update Codex client models configuration and instructions for `gpt-6-astra`.
- Bump default Codex client version and user-agent to `0.153.3` in model fetcher tool.
- Responses API: only hoist developer/system messages before conversation starts to systemInstruction, keeping token 0 cache prefix immutable. Demote mid-session developer messages to user role and merge consecutive user turns via MergeAdjacentGeminiUserContents without crossing functionResponse boundaries.
- Tool Call Buffer: buffer mid-session developer messages during pending function calls and emit after functionResponse, preserving valid tool pairing and reason replay.
- Chat Completions API: apply the same leading/mid-session distinction for system/developer messages and guard against empty parts.
- Claude Messages API: align role: "developer" in messages with role: "system", demoting to <system-reminder> user turns and avoiding upstream 400s.
- Validation: update ValidateGeminiFunctionCallPairing to allow intervening user turns before functionResponse, matching upstream Antigravity tolerance.
- Role Normalization: ensure functionResponse turns in Antigravity are always normalized to role: "user".
- Require exactly one non-reminder text block matching quota/test/probe/./Hi for probe request matching.
- Identify title helper requests via expanded session title patterns.
- Implement post-payload bidirectional probe reclassification: strip CPA diagnostics and billing tags on probes, while restoring continuity if declassified.
- Preserve caller-owned and payload-supplied diagnostics on probe requests.
- Gate late sensitive-word obfuscation strictly on cloaked requests in Execute and ExecuteStream.
- Add comprehensive end-to-end tests for probe classification, diagnostics isolation, and late cloaking.
- Inject '# Reporting outcomes' system block for Fable 5.1 / Mythos 5.1 models matching Claude Code 2.1.258 tengu_dapper_lagoon behavior.
- Support both string-format and block-array system prompts for Fable reporting injection.
- Add reconcileClaudeCodeFableModelAfterPayload to reconcile model additions when payload rules override model or thinking.
- Reliably re-add reporting block if omitted after payload rules modify system blocks.
- Drop injected thinking.display on Fable models when payload changes thinking type from adaptive to disabled.
- Enhance payload rule path tracking with ancestor target matching in ApplyPayloadConfigWithTrackedPaths.
- Introduce 2.1.258 dynamic betas: thinking-display-updates-2026-08-18, server-side-fallback-2026-06-01, and fallback-credit-2026-03-24.
- Prune effort-2025-11-24 on Haiku models, probes, and when thinking is disabled.
- Prune thinking-display-updates on disabled thinking and probe/helper turns.
- Identify Fable 5.1 / Mythos 5.1 models with boundary checks and inject default fallbacks and adaptive thinking display.
- Strictly pair 1h cache control with extended-cache-ttl-2025-04-11, stripping TTL on probes and subagents.
- Assemble x-anthropic-billing-header strictly following official 2.1.258 binary sequence: cc_version -> cc_entrypoint -> cch -> cc_workload -> cc_is_subagent -> cc_prev_req -> cc_prompt_id.
- Track upstream request-id in thread-safe bounded session continuity state and inject into subsequent turns as cc_prev_req.
- Generate and enforce RFC 4122 UUIDv4 cc_prompt_id per user prompt turn, preserving it across tool continuations while suppressing it on probes and title helpers.
- Detect subagents via agent headers and session metadata to emit cc_is_subagent=true.
- Harmonize diagnostics and continuity lifecycles to prevent uncommitted or truncated streams from corrupting state.
- Exclude x-anthropic-billing-header system blocks from sensitive-word zero-width space injection.
Enforce strict monotonic offset ordering (replacement.start <= last) when
splicing degraded tool provenance IDs to reject unknown zero offsets and
prevent overwriting the payload prefix.
- Implement three-way merge for refreshed and prepared auth updates against base and current runtime state.
- Retain user modifications to metadata, attributes, proxy URL, and error/cooldown status across background refresh operations.
- Guard against stale registration epochs and enforce per-auth generation ordering during persistence.
Closes: #5465
- Recursively inspect JSON schema properties to detect optional fields not listed in the `required` array.
- Downgrade `strict` to false when schemas contain optional properties to prevent backend HTTP 400 rejections.
Closes: #5463
- Prefix colliding tool names (`read_file`, `write_file`, `execute_code`) with `external_` when sending requests upstream to Antigravity models.
- Strip the `external_` prefix from Antigravity responses so clients receive the original tool names.
- Apply the name mapping across tool definitions, tool calls, tool results, and tool choice in both Chat Completions and Responses translators.
Closes: #5462
- Bump plugin schema version to 5 and introduce `SchemaVersionStreamChunkOmitHistory`.
- Omit `HistoryChunks` on payload stream chunks for schema version 5+ to avoid per-chunk cloning and serialization overhead.
- Conditionally accumulate and clone history chunks only when legacy plugins with schema version < 5 are active.
Closes: #5451
- Map Claude `max_tokens` stop reason to `response.incomplete` with `max_output_tokens` incomplete details.
- Propagate `incomplete` status to trailing output items across streaming and non-streaming responses.
- Defer and track output item finalization to ensure correct status and arguments when turns are truncated.
Closes: #5439
- Cache token usage metrics from streaming chunks instead of prematurely finalizing content blocks.
- Defer `message_delta` and `message_stop` emissions until encountering a finish reason, a trailing usage chunk, or stream completion.
Closes: #5419
- Add `writePing` to responses websocket writer to emit Ping control frames.
- Send periodic keep-alive Ping frames based on streaming configuration during response forwarding.
- Reset keep-alive interval upon receiving data chunks and abort session if ping write fails.
Closes: #5413
- Add `codex.orphan-delegation-compatibility` configuration option and mirror it to SDK configuration.
- Convert orphan Codex delegation outputs into standard user messages for requests with `X-Openai-Subagent: collab_spawn`.
- Integrate orphan delegation rewriting into OpenAI responses request handling pipeline.
Closes: #5401
- Add routing.session-affinity-subagents (defaulting to true) to RoutingConfig.
- Unify subagent parent credential inheritance across all providers by removing hardcoded provider/model blacklists.
- When session-affinity-subagents is false, isolate subagents and distribute them via the fallback selector.
- Ensure changing session-affinity-subagents is a no-op when session-affinity is false.
- Preserve alias isolation and failure isolation invariants.
Closes: #5417
- Bump default Claude Code version baseline from 2.1.220 to 2.1.258 to resolve upstream 400 version gate error
- Update Stainless SDK package version to 0.112.1 and runtime version to v26.3.0
- Refresh default device profile, billing header build hashes, and cloaking signatures
- Decouple unconfirmed client OS/Arch test assertions from host runner platform
- Update config.example.yaml and test suites across executor and helps packages
- Enforce a 10-second minimum cooldown floor for quota errors to prevent retry storms from sub-second `Retry-After` values.
- Track attempted authentication credentials per round across execution flows.
- Ensure credentials attempted during a failed 429 round respect the cooldown floor instead of triggering zero-wait retries.
Closes: #5265
- Map `user_credits_insufficient` to `402 Payment Required` in `decodeHomeDispatchError`.
- Map `user_period_limit_exceeded` to `429 Too Many Requests` in `decodeHomeDispatchError`.
- Add unit test coverage for billing and period limit error mappings.
Closes: #5170
- Parse and prioritize JWT `exp` claims when determining access token expiration.
- Retain active credentials and schedule backoff retries on refresh failures if the access token remains unexpired.
- Demote and block auth credentials with expired access tokens during model scheduling and candidate selection.
- Reduce Codex token refresh lead duration to 24 hours.
Closes: #5095
- Add `claude-fable-5-1` model definition with thinking configuration and multimodal capabilities.
- Add `gemini-3.8-flash` and `gemini-3.8-flash-high` model definitions across Google and Antigravity registries.
- Bypass short cooldown checks and recording in execution flows when cooling is disabled globally or per auth.
- Skip marking credits permanently disabled and refreshing credit hints when cooling is disabled.
- Export quota cooldown status helper functions for auth and configuration evaluations.
Closes: #4793
- Use `context.AfterFunc` and buffered delivery in websocket relay sessions to avoid per-request goroutine leaks.
- Synchronize in-flight puts and drain queued connections upon mux listener close.
- Ensure home streaming log writer goroutines terminate cleanly when the log client is unhealthy.
- Prevent integer arithmetic overflow in token breakdown validations and calculations.
- Clone request headers in logging middleware to prevent concurrent mutation issues.
- Implement standard `io.WriterTo` return signature for file body sources.
Closes: #4709
- Retry model fetch requests up to twice per endpoint before falling back to subsequent base URLs.
- Prioritize the daily base URL ahead of production in the default endpoint list.
- Allow injecting custom base URLs and HTTP clients to support testing and configurable fetch execution.
Closes: #4495
