feat: surface team member activity in AG-UI via ACTIVITY_SNAPSHOT

[ProgrammerPlus1998]

Summary

Team runs streamed through AG-UI previously folded every member's output into a single assistant message (with a "Team member: " prefix), so clients could not tell which member produced which content — see #9243.

This change surfaces each team member's live progress through AG-UI's native Activity channel instead of flattening:

• Member chunks emit ACTIVITY_SNAPSHOT events (activity_type: "agno.team_member"), keyed by a stable per-member message_id.
• Each snapshot carries agentId, agentName, runId, parentRunId, a status lifecycle (running → tool_calling → completed), currentTool, and the member's accumulated text.
• The leader's own output continues to stream as TEXT_MESSAGE_*; member text is no longer folded into the leader's message.
• No new config: member activity is emitted whenever member events are present (stream_member_events=True). Hiding member output is still controlled upstream via stream_member_events=False.

Fixes #9243

Why Activity instead of separate text messages

AG-UI's ACTIVITY_* events are the protocol-native mechanism for "what each agent is doing" as a side-channel, decoupled from the main chat bubbles. Each member gets an addressable message_id, so interleaved/parallel member execution (nested teams) can't corrupt a single shared message — the failure mode a "one text message per member" approach has on frontends that assume a single active text bubble.

Implementation

• StreamState: per-member message_id + mutable snapshot content tracking (get_or_create_member).
• handlers: _is_member_chunk() discriminator (agent-level event with non-None parent_run_id, set by team delegation); member run_content / tool_call_started / tool_call_completed / run_content_completed → ACTIVITY_SNAPSHOT; leader path unchanged.
• Removed the member_responses folding and the "Team member: " prefix from _extract_team_response_chunk_content.

Type of change

• New feature

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Checklist

• Code complies with style guidelines
• Ran format/validation scripts (./scripts/format.sh and ./scripts/validate.sh)
• Self-review completed
• Documentation updated (comments, docstrings)
• Examples and guides: Relevant cookbook examples have been included or updated (research_team.py + TEST_LOG.md)
• Tested in clean environment
• Tests added/updated (test_agui_member_activity.py — 7 tests)

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Additional Notes

Validation performed:

• 7 new unit tests + full existing AG-UI suite (70 tests) pass.
• End-to-end through the real pipeline (run_entity → event translation): member chunks produce per-member ACTIVITY_SNAPSHOTs reaching status="completed"; member text never appears in leader TEXT_MESSAGE_CONTENT; leader final summary appears only in the leader message. Confirmed with both a mocked model and a real model, including a member that calls a tool (observed tool_calling snapshots).

[lucabecchetti]

any news to merge this?

[ProgrammerPlus1998]

Hi @kausmeows @ysolanky — rebased onto v3.0.0. The bundled ag-ui-protocol already supports ACTIVITY_SNAPSHOT, and the os/interfaces suite passes (92 tests, including the new member-activity coverage).

Ready for review, thanks!

[lucabecchetti]

any news for a timeline?

[lucabecchetti]

Hi, I saw that 3.0.1 has been released, but #9253 is not included. Is there anything still blocking the merge, or is the fix planned for a future release?

Just trying to understand the expected timeline. Thanks!

[ProgrammerPlus1998]

I suspect the developers still have some P0 issues caused by major version changes to fix, and haven't had time to address these functional problems yet. You can ask the developers for help.

[lucabecchetti]

Hi @kausmeows @ysolanky, just following up on #9253.

Since 3.0.2, 3.0.3, 3.04 and 3.0.5 have now been released and #9253 is still not included, is there any specific blocker preventing the review/merge?

The fix is still relevant for us because we need to preserve the Team member identity in the AG-UI stream.

Thanks!