Distillation

Date: Sep 16, 2026

• 🟡 (20:21) Inspection of packages/gateway/src/pipeline.ts lines 8385–9203 showed strict Responses-stream lifecycle validation: events after response.output_item.done are rejected; duplicate identities and duplicate reasoning-summary completions are detected; function-call argument completion must match streamed arguments; response.output_item.done cannot change content type or finalized values; and terminal events cannot change response identity.
• 🟡 (20:21) The Responses stream handler tracks function-call identity using callId and name, validates output-item/content indexes and statuses, and compares completed content against previously accumulated streamed state.
• 🟡 (20:21) Terminal-event handling normalizes raw events, rejects processing after lifecycle.terminal, checks that non-in_progress response status is lifecycle-consistent, and throws "Responses terminal event changed response identity" when the terminal response differs from the accumulated response identity.