feat(api): make function call output call IDs optional

[apcha-oai]

Summary

Align function call output types with the API schema: call_id is optional in stable and beta input and response types, and input types also accept null.

Agents SDK change is expected / will need to be fixed after this PR merges.

[github-actions]

Castiron custom code

✅ No new custom-code files detected.

34 mixed files remain; 0 existing customizations changed; 1 generated baselines changed.

Compared a64dd8ffc78a → ad57609d20e9. Generated baselines verified.

File	Result	Current custom patch
src/openai/resources/realtime/realtime.py	Generated baseline changed	+65 / −32

33 existing customizations unchanged

• api.md
• scripts/castiron/README.md
• scripts/castiron/custom_code_report.py
• scripts/castiron/test_custom_code_report.py
• src/openai/init.py
• src/openai/_client.py
• src/openai/resources/audio/transcriptions.py
• src/openai/resources/audio/translations.py
• src/openai/resources/beta/beta.py
• src/openai/resources/beta/responses/responses.py
• src/openai/resources/beta/threads/runs/runs.py
• src/openai/resources/beta/threads/threads.py
• src/openai/resources/chat/completions/completions.py
• src/openai/resources/embeddings.py
• src/openai/resources/files.py
• src/openai/resources/responses/responses.py
• src/openai/resources/uploads/uploads.py
• src/openai/resources/vector_stores/file_batches.py
• src/openai/resources/vector_stores/files.py
• src/openai/resources/videos.py
• src/openai/resources/webhooks/init.py
• src/openai/resources/webhooks/webhooks.py
• src/openai/types/chat/init.py
• src/openai/types/chat/chat_completion_message_tool_call.py
• src/openai/types/fine_tuning/fine_tuning_job_integration.py
• src/openai/types/responses/init.py
• src/openai/types/responses/response.py
• src/openai/types/responses/response_function_web_search.py
• src/openai/types/responses/response_function_web_search_param.py
• src/openai/types/responses/tool.py
• src/openai/types/responses/tool_param.py
• src/openai/types/webhooks/init.py
• tests/api_resources/test_videos.py

A changed generated baseline means this report cannot reliably identify which handwritten lines changed.

Inspect the custom-code diff

Download the exact patch produced by this run (requires repository access):

gh run download 33023523404 --repo openai/openai-python \
  --name castiron-custom-code-33023523404-1 --dir /tmp/castiron-custom-code-33023523404-1
git apply --stat /tmp/castiron-custom-code-33023523404-1/custom-code.patch
cat /tmp/castiron-custom-code-33023523404-1/custom-code.patch

Or reproduce it from an SDK checkout containing the vendored reporter:

git fetch --no-tags origin a64dd8ffc78a5892ff612a48dc88c99b27478135 ad57609d20e96916092d7dae7a64acc7edc720cc
python3 scripts/castiron/custom_code_report.py report \
  --base a64dd8ffc78a5892ff612a48dc88c99b27478135 \
  --head ad57609d20e96916092d7dae7a64acc7edc720cc --fetch --require-head-hash --public \
  --out /tmp/castiron-custom-code-ad57609d20e9
cat /tmp/castiron-custom-code-ad57609d20e9/custom-code.patch

This is the current full custom patch for mixed files, not an attribution of only the handwritten lines changed by this PR.

Full report and patch

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-08-26T23:18:20.275758Z	ad57609	Draft marked ready
🔒 Security Review	✅ Completed 2026-08-26T23:19:19.983803Z	ad57609	Draft marked ready

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[openai-sdks]

OkTest Summary

✅ 237/237 SDK tests passed in 11.602s for Python SDK PR #3738.

Test results — 42 files

Test	Result	Time
tests/chat-completions-complex-body.test.ts	✅ Passed	189ms
tests/chat-completions-create.test.ts	✅ Passed	263ms
tests/chat-completions-stream.test.ts	✅ Passed	127ms
tests/files-content-binary.test.ts	✅ Passed	208ms
tests/files-create-multipart.test.ts	✅ Passed	165ms
tests/files-list-pagination.test.ts	✅ Passed	172ms
tests/initialize-config.test.ts	✅ Passed	154ms
tests/instance-isolation.test.ts	✅ Passed	205ms
tests/models-list.test.ts	✅ Passed	127ms
tests/responses-background-lifecycle.test.ts	✅ Passed	216ms
tests/responses-body-method-errors.test.ts	✅ Passed	324ms
tests/responses-cancel-timeout.test.ts	✅ Passed	194ms
tests/responses-cancel.test.ts	✅ Passed	215ms
tests/responses-compact-retries.test.ts	✅ Passed	431ms
tests/responses-compact.test.ts	✅ Passed	323ms
tests/responses-create-advanced-stream.test.ts	✅ Passed	146ms
tests/responses-create-advanced.test.ts	✅ Passed	280ms
tests/responses-create-disconnect.test.ts	✅ Passed	1.303s
tests/responses-create-errors.test.ts	✅ Passed	217ms
tests/responses-create-malformed-api-responses.test.ts	✅ Passed	273ms
tests/responses-create-retries.test.ts	✅ Passed	376ms
tests/responses-create-stream-failures.test.ts	✅ Passed	133ms
tests/responses-create-stream-timeout.test.ts	✅ Passed	208ms
tests/responses-create-stream-wire.test.ts	✅ Passed	3.956s
tests/responses-create-stream.test.ts	✅ Passed	340ms
tests/responses-create-terminal-states.test.ts	✅ Passed	246ms
tests/responses-create-timeout.test.ts	✅ Passed	199ms
tests/responses-create.test.ts	✅ Passed	263ms
tests/responses-delete.test.ts	✅ Passed	199ms
tests/responses-input-items-errors.test.ts	✅ Passed	402ms
tests/responses-input-items-list.test.ts	✅ Passed	353ms
tests/responses-input-items-options.test.ts	✅ Passed	402ms
tests/responses-input-tokens-count-timeout.test.ts	✅ Passed	242ms
tests/responses-input-tokens-count.test.ts	✅ Passed	222ms
tests/responses-malformed-inputs.test.ts	✅ Passed	3.028s
tests/responses-not-found-errors.test.ts	✅ Passed	263ms
tests/responses-parse.test.ts	✅ Passed	468ms
tests/responses-retrieve-retries.test.ts	✅ Passed	242ms
tests/responses-retrieve.test.ts	✅ Passed	239ms
tests/responses-stored-method-errors.test.ts	✅ Passed	591ms
tests/retry-behavior.test.ts	✅ Passed	3.116s
tests/sdk-error-shape.test.ts	✅ Passed	271ms

View OkTest run #33022779745

_{SDK merge (7551d7e0bc76) · head (ad57609d20e9) · base (a64dd8ffc78a) · OkTest (2b1bdfd25e98)}

[jbeckwith-oai]

The required Agents SDK integration check is failing on this exact head because the new optional call_id flows into an unchanged Chat Completions tool message that still requires a non-null string. This is a demonstrated coordinated-release regression, not an unrelated preexisting failure; update/coordinate the dependent Agents converter and restore the required check before releasing.

[jbeckwith-oai]

Approved with the explicitly documented rollout exception: the Agents SDK type-check failure is expected for this coordinated optional-call-ID release and will be fixed forward after the Python SDK ships. Generated stable/beta input and output optionality otherwise matches the canonical API contract.