[Samecho]

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Link to Issue or Description of Change

• Related: RemoteA2aAgent never follows an interrupted peer task (A2A spec 7.6.2): a peer resumed out-of-band leaves the caller stuck #7811

Problem:

A task-mode peer can finish after receiving a confirmation directly. When the caller later resumes, it still sends a message to the completed task and returns a terminal-state error instead of the result.

Solution:

Read the recorded peer task before continuing the paused delegation. If it completed with a successful finish_task response, recover the matching call's arguments from the task snapshot or its agent history and complete the delegation with the existing output-schema handling. Keep the caller context from the before-request hooks, and persist only the lookup status rather than the peer's private history.

The check uses the latest paused task in the current delegation and context. A peer still waiting for input follows the existing send path. Custom inbound converters and after-request hooks retain their existing routing behavior.

Testing Plan

Unit Tests:

• I have added or updated unit tests for my change.
• All unit tests pass locally. See the baseline failures below.

All eight main regression cases fail against unchanged production code at 392feb2. They cover both converter paths, wrapped and primitive output, and completion calls stored in the task snapshot or history. Additional cases cover mismatched tasks, user-authored history, lookup errors, private-input persistence and caller context. Existing continuation tests also check that stale or unrelated tasks are not queried.

Local A2A suites: 977 passed with SDK 1.2.3; 1005 passed with SDK 0.3.26. The local type comparison introduced no new errors, and applicable pre-commit checks passed.

The Linux fork run passed pre-commit, the full-project type comparison on Python 3.11–3.13, and the A2A 0.3, A2A 1.2.3 and MCP v2 suites on Python 3.11–3.14. Both installed-wheel E2E checks passed.

Full unit-suite results:

Python	Passed	Failed	Skipped
3.11	22,034	14	96
3.12	22,025	14	97
3.13	22,025	14	97
3.14	22,027	14	95

Each run has the same 14 baseline failures: the custom-factory test with A2A SDK 1.3 (_httpx_client, tracked in #7777) and 13 telemetry schema comparisons. I reran those tests against unchanged 392feb2 in the same resolved environment; the failing test IDs and error messages match exactly. The full-suite jobs remain red, and no tests were excluded to hide these failures. Each version also reports 12 expected failures and 2 unexpected passes.

Manual End-to-End (E2E) Tests:

Adapted the reporter's in-process setup to serve the peer as an ADK task-mode agent. Before the fix, resuming the caller sends another message to the completed task and returns an error. With the fix, both executor versions retrieve the result with GetTask, the coordinator completes, and the tool executes once. No live model or cloud credentials are needed.

The fork also checks this flow from an installed wheel. Validation run.

Checklist

• I have read the CONTRIBUTING.md document.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have added tests that prove my fix is effective or that my feature works.
• New and existing unit tests pass locally. See the full-suite results.
• I have manually tested my changes end-to-end.
• Any dependent changes have been merged and published in downstream modules. No dependent changes are required.

Additional context

This addresses the next-turn reconciliation step in #7811 for ADK task-mode peers. Background subscription, polling and automatic caller wake-up remain separate work. Completion without a finish_task marker is covered by #7251; this change keeps that path unchanged.

Prepared with Codex.