fix: bubble up subagent HITL approval to parent agent#1478
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jsonmp-k8 wants to merge 1 commit intokagent-dev:mainfrom
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fix: bubble up subagent HITL approval to parent agent#1478jsonmp-k8 wants to merge 1 commit intokagent-dev:mainfrom
jsonmp-k8 wants to merge 1 commit intokagent-dev:mainfrom
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Pull request overview
This PR addresses subagent “human-in-the-loop” (HITL) deadlocks by detecting when a RemoteA2aAgent subagent enters input-required, surfacing that approval request to the top-level task, and forwarding the user’s decision back to the subagent on resume.
Changes:
- Detect subagent
input-requiredvia ADK eventcustom_metadata["a2a:response"]and persist subagent HITL context in session state. - On HITL resume, route the decision to the subagent over its A2A client, then re-run the parent agent to continue.
- Add unit tests for the new helper methods used for subagent HITL detection/message extraction.
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 8 comments.
| File | Description |
|---|---|
python/packages/kagent-adk/src/kagent/adk/_agent_executor.py |
Adds subagent HITL detection, session-state persistence, and resume forwarding logic for RemoteA2aAgent. |
python/packages/kagent-adk/tests/unittests/test_hitl.py |
Adds unit tests for subagent HITL helper methods. |
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When subagents with HITL-enabled tools enter input_required state, the parent agent now detects this from the A2A response metadata and propagates the approval request to the top-level chat. On resume, the decision is forwarded directly to the subagent via its A2A client, and the parent agent re-runs to process the result. Key implementation details: - Detect subagent input_required via ADK event custom_metadata - Persist subagent HITL context in session state for resume - Forward decisions to subagents with 5-minute timeout - Clear HITL state after successful forwarding - Use SubagentForwardResult NamedTuple for type-safe return values - Extract shared helpers to avoid code duplication - Prefer public APIs with private API fallbacks for forward compat - Emit terminal failure events for all error paths - Add comprehensive unit tests for all helper methods Fixes kagent-dev#1475 Signed-off-by: Jaison Paul <paul.jaison@gmail.com>
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When subagents with HITL-enabled tools enter input_required state, the parent agent now detects this from the A2A response metadata and propagates the approval request to the top-level chat. On resume, the decision is forwarded directly to the subagent via its A2A client, and the parent agent re-runs to process the result.
Key implementation details:
Fixes #1475