[pacocartones]

Summary

• When a Chat Completions upstream served a /v1/responses client without streaming, the response always said status: "completed", even when the upstream stopped on length or content_filter. The client had no signal that the output was cut off.
• After the conversion, the non-streaming path now applies finalizeResponsesTerminalStatus, the rule the streaming path got in fix(responses): surface truncated generations as response.incomplete, not completed #14806, so the client gets status: "incomplete" with incomplete_details.
• The change is at the call site in chatCore/nonStreamingClientTranslate.ts, because responseSanitizer.ts is at its frozen file-size ceiling.

Related Issues

• Related to fix(responses): surface truncated generations as response.incomplete, not completed #14806

Target Branch

• Base is the active release/v3.8.x branch (the highest open release/v*), not main
• New feature? From 3.8.55 on it is held with the v4-feature label for the v4 channel

Validation

• Change type: other (responses / chatCore)
• Focused tests and category gates from the golden path
• npm run lint (eslint on the changed files: clean)
• Reconciled with the current active release base; focused checks rerun afterward
• Production-code changes include a new or updated automated test in this PR

Tests Added Or Updated

• tests/unit/responses-client-incomplete-nonstreaming.test.ts (new): 3 tests through translateNonStreamingClientResponse. 2 fail on the base and all 3 pass with the fix. The one that already passes checks that a clean stop stays completed.

Coverage Notes

• open-sse/handlers/chatCore/nonStreamingClientTranslate.ts, Responses client branch.

Reviewer Notes

• A native Responses body (no choices) is not touched: it keeps the upstream's own status.
• On the previous release head (7f3cbb0) the 4 test files that import these modules passed 34/34. On the current head (e23fb0f) the new test is 3/3 with the fix and 2/3 fail without it.
  ⚠️ base-red inherited: 🔴 Release branch not green: release/v3.8.52 #15306