[cunninghamcard-bit]

Summary

Before: an OpenAI or Azure Responses stream that never received response.created finished with providerMetadata.<key>.responseId: "".

After: as in @ai-sdk/openai 4.0.83, it finishes with responseId: null. The generate path already wrote null for a missing id.

Found while porting the upstream Azure tests (case responses › doStream › should handle file_citation annotations without optional fields in streaming). Part of the #276 list.

How it works today

OpenAIResponsesLanguageModel::do_stream
└─ ResponsesStreamTransformer
   ├─ "response.created" → response_id = response.id                 aimux-providers/src/openai/responses/responses_convert.rs:740
   └─ flush → Finish { provider_metadata: { <key>: { responseId: response_id.unwrap_or_default() } } }   :1517
                                                ← upstream: let responseId: string | null = null   (openai-responses-language-model.ts:1587)
                                                   flush → providerMetadata.responseId: responseId → null   (:2932)
convert_responses_generate → { responseId: data.id or null }        responses_convert.rs:328   (already null)

What this PR changes

let mut pm = json!({ "responseId": self.response_id });   responses_convert.rs:1517   (None → null)

Tests (tests/openai_upstream_e2e_test.rs): a_stream_without_response_created_finishes_with_a_null_response_id streams only response.completed; on master it fails with left: String(""), right: Null. The upstream case is ported in the Azure test PR.

Docs: CHANGELOG Fixed.

Type of change

• Bug fix (non-breaking)
• New feature (non-breaking)
• Breaking change
• New provider
• New / updated binding
• Docs / RFC

Checklist

• cargo +1.99 fmt -p aimux-providers -- --check passes
• cargo +1.99 clippy -p aimux-providers --lib --tests -- -D warnings passes
• cargo +1.99 test -p aimux-providers --test openai_upstream_e2e_test passes (23)
• scripts/check_provider_boundaries.sh passes
• Updated relevant docs (CHANGELOG)
• Commit messages follow Conventional Commits

Notes for reviewers

Second of three OpenAI fixes (#321 file search integer ← this PR ← reasoning delta item id ← the Azure test PR). Nothing in the workspace reads responseId back from the finish metadata.

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Generated by Claude Code

[cunninghamcard-bit]

Folded into #323 together with the other OpenAI fixes, so each vendor has one fix PR. This change is commit 595eedc2 there. Closing this one; the branch stays as it is.

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Generated by Claude Code