[sophia-ramsey]

Motivation & Context

Tokenless intermediate streaming updates currently overwrite an active continuation token, incorrectly indicating that the provider operation has completed. This change preserves the token while an operation remains in progress and clears it when the operation reaches a terminal state, including after responses are buffered and converted back into updates.

Description & Review Guide

• What are the major changes? This PR adds a private operation-state marker to chat and agent responses and updates. The marker distinguishes in-progress and terminal operations while leaving unspecified updates with their existing behavior for provider compatibility. _OperationState is preserved through aggregation, response-to-update conversion, workflow forwarding, and buffered middleware. OpenAI completed, incomplete, and failed events and A2A completed, failed, canceled, and rejected states are marked terminal; intermediate provider updates are marked in_progress.
• What is the impact of these changes? Streaming responses no longer lose an active continuation token when a provider omits the token from an intermediate update. Terminal operations clear the token reliably, including after buffering or response round-trips. Existing providers that do not set operation state retain their current token-handling behavior, and the private marker does not change the public serialized response shape.
• What do you want reviewers to focus on? Whether the private compatibility-preserving operation state is straightforward, whether it covers aggregation and buffering without affecting existing provider behavior, and whether the OpenAI and A2A classifications correctly represent in-progress and terminal operations.

Related Issue

Fixes #8826

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]

Copilot review overview

🟡 Changes recommended

Completed responses converted with to_updates() can still fail to clear a previously aggregated continuation token.

Review effort: Balanced
Findings: 1

Open (1)

• Mark response tail update terminal when no continuation token · New

What changed in this PR

Adds explicit terminal-state signaling so streaming aggregation preserves active continuation tokens until completion.

Changes:

• Adds and propagates is_operation_terminal.
• Marks terminal OpenAI and A2A events.
• Adds aggregation and provider regression tests.

File	Description
python/​packages/​core/​agent_framework/​_types.py	Adds terminal signaling and token aggregation logic.
python/​packages/​core/​agent_framework/​_workflows/​_agent.py	Propagates terminal state through workflows.
python/​packages/​core/​tests/​core/​test_types.py	Tests aggregation, mapping, and serialization.
python/​packages/​core/​tests/​workflow/​test_workflow_agent.py	Tests workflow metadata propagation.
python/​packages/​openai/​agent_framework_openai/​_chat_client.py	Marks terminal Responses API events.
python/​packages/​openai/​tests/​openai/​test_openai_chat_client.py	Tests OpenAI terminal handling.
python/​packages/​a2a/​agent_framework_a2a/​_agent.py	Emits A2A terminal markers.
python/​packages/​a2a/​tests/​test_a2a_agent.py	Tests A2A completion and artifact streams.

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[github-code-quality]

Code Coverage Overview

Languages: Python

Python / code-coverage/python

The overall line coverage in commit 46d13cd in the sramsey/python-conti... branch remains at 92%, unchanged from commit 91ab44f in the main branch.

Show a line coverage summary of the most impacted files.

File	main 91ab44f	sramsey/python-conti... 46d13cd	+/-
packages/a2a/ag...k_a2a/_agent.py	95%	94%	-1%
packages/openai..._chat_client.py	94%	94%	0%
packages/core/a...ework/_types.py	96%	96%	0%
packages/core/a...flows/_agent.py	91%	91%	0%

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_{Updated October 08, 2026 23:51 UTC}

[github-actions]

MAF Automated Review — Iteration 1

Result: Findings reported
Scope: full PR (2 commit(s)): d298983a1397, 2b67d6b3571d
Model: gpt-5.6-sol

Overview

The PR introduces an explicit terminal-operation signal and applies it consistently in the changed A2A, OpenAI, chat-to-agent, and workflow-update paths, with focused tests for token preservation, terminal clearing, serialization, and artifact deduplication. The remaining risk is in compatibility paths outside those direct producers: response-to-update round-trips discard the new signal, and existing custom providers do not emit it, so both paths can retain stale continuation tokens after completion.

Reviewed the supplied pull-request change set across correctness, security/reliability, architecture, and failure behavior.
2 verified findings remained after source verification (2 medium) across 1 file. Details are attached to the affected lines below.

Affected areas: python/packages/core/agent_framework/_types.py

[Eduard van Valkenburg (eavanvalkenburg)]

sophia-ramsey The response round-trip still drops terminality: ChatResponse.to_updates() / AgentResponse.to_updates() copy tail metadata but not is_operation_terminal, and aggregation has no representation that preserves it. Buffered middleware can therefore turn a terminal update into a nonterminal sequence or retain stale token state; existing providers’ final tokenless updates also default nonterminal. This needs an explicit preserved representation and compatibility coverage before the public flag shape is settled.

[Eduard van Valkenburg (eavanvalkenburg)]

Copilot the last commit broke everything, please fix

[Copilot]

Copilot the last commit broke everything, please fix

Restored the missing Generic import in aea1a64. Syntax and whitespace checks pass; I couldn't run pytest because uv and pytest are unavailable in this environment.

[Jose Alvarez (jpalvarezl)]

Found two continuation-lifecycle gaps not covered by the existing review threads; details are attached inline.

[Jose Alvarez (jpalvarezl)]

The two follow-up commits address the outstanding continuation-lifecycle findings: operation state now survives update serialization round-trips, and OpenAI streaming error/terminal-created events clear resume state and surface errors. The added regressions cover both paths, and the current CI suite is fully green.