Python: Preserve approval decisions under OpenAI continuation

[eavanvalkenburg]

Motivation & Context

OpenAI service-side continuation already stores the approval request, but the current serializer drops the new
approval response as well. The service therefore never receives the user's approved or rejected decision.

Description & Review Guide

• What are the major changes?
  • Continue omitting the already stored function_approval_request.
  • Always serialize the current function_approval_response as mcp_approval_response.
  • Cover approved and rejected decisions with and without service-side storage.
• What is the impact of these changes?
  • Approval-paused OpenAI Responses runs can resume under previous_response_id or conversation continuation.
  • Stored server-issued request items are still not duplicated.
  • Stateless behavior remains unchanged.
• What do you want reviewers to focus on?
  • The request-versus-response storage boundary.
  • Approved/rejected payload parity.

Related Issue

Fixes #7125

Contribution Checklist

• The code builds clean without any errors or warnings
• All unit tests pass, and I have added new tests where possible
• The PR follows the Contribution Guidelines
• This PR is linked to an issue and there is no other open PR for this issue (see Related Issue above).
• This is not a breaking change. If it is a breaking change, add the breaking change label (or add "[BREAKING]" to the title prefix, before or after any language prefix) — a workflow keeps the label and title prefix in sync automatically.

[Copilot]

Pull request overview

This PR fixes OpenAI Responses API continuation under service-side storage by ensuring the user’s tool-approval decision is not dropped during serialization, so approval-paused runs can reliably resume with previous_response_id / conversation_id.

Changes:

• Update the OpenAI chat client serializer to skip only stored function_approval_request items under service-side storage, while still serializing function_approval_response as mcp_approval_response.
• Expand unit test coverage to validate both approved and rejected decisions under storage-on vs storage-off behavior.
• Document the request/response storage boundary and update the function-calling loop spec to reflect the covered scenario.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
python/packages/openai/agent_framework_openai/_chat_client.py	Stops stripping function_approval_response under service-side storage, preserving approval decisions for continuation.
python/packages/openai/tests/openai/test_openai_chat_client.py	Adds parameterized test coverage ensuring approval responses are kept (approved/rejected) while requests are omitted under storage.
python/packages/openai/AGENTS.md	Documents how approval request vs response behave under service-side continuation and warns about manual history replay.
docs/specs/004-python-function-calling-loop.md	Updates required invariants/coverage lists to include service-side approval decision behavior and its regression test.

[github-actions]

Python Test Coverage Report •

File	Stmts	Miss	Cover	Missing
packages/openai/agent_framework_openai
_chat_client.py	1370	117	91%	312, 325, 675–679, 687–690, 696–700, 750–757, 759–761, 768–770, 828, 836, 859, 1076, 1135, 1137, 1139, 1141, 1207, 1221, 1301, 1311, 1316, 1359, 1471–1472, 1487, 1760, 1867, 1872–1873, 1956, 1966, 1993, 1999, 2009, 2015, 2020, 2026, 2031–2032, 2112, 2156, 2159–2162, 2176, 2186–2187, 2199, 2241, 2306, 2323, 2326, 2353–2355, 2394, 2411, 2414, 2476, 2483, 2520–2521, 2556, 2594–2595, 2613–2614, 2786–2787, 2805, 2891–2899, 3077, 3092, 3142, 3152–3154, 3181–3183, 3193–3194, 3200, 3215, 3348–3349
TOTAL	45842	4474	90%

Python Unit Test Overview

Tests	Skipped	Failures	Errors	Time
9460	34 💤	0 ❌	0 🔥	1m 58s ⏱️

[TaoChenOSU]

nit: this is a bit confusing since OpenAI never issues function approval requests. It only has one approval request type for mcp.