AG-UI Strands adds subagent visibility and attribution events while fixing parallel snapshot ownership and nested closure
AG-UI released @ag-ui/aws-strands 1.0.2 and ag_ui_strands 1.0.3 on November 9. The Python adapter adds inline, attributed, and hidden subagent visibility. Attributed mode emits start, finish, and error events and carries subagentRunId on text, reasoning, and tool calls. The release also fixes nested-subagent closure, open inner tool calls at arbitrary depth, parallel snapshot ownership, and loss of completed history when a sibling is interrupted.
Why it matters
When several agents drive one interface concurrently, the frontend needs to know which subagent owns each message, reasoning segment, and tool call. It also needs one branch's interruption to leave another branch's snapshot intact. Explicit attribution and independent snapshots are foundational for understandable progress, local error presentation, recovery, and auditing.
A closer look
subagent_visibility defaults to inline, preserving prior behavior. Attributed mode adds SUBAGENT_STARTED, SUBAGENT_FINISHED, SUBAGENT_ERROR, and subagentRunId; hidden suppresses subagent events. The Python and TypeScript packages allow opting out of forced A2UI tool choice while retaining forced choice when configuration is null. The TypeScript adapter also forwards tracing baggage across SDK versions. The release declares no breaking changes for either package.
Who this is for
Frontend, agent-platform, and observability teams using AWS Strands, AG-UI, multi-agent tool calls, parallel state, or A2UI.
Original sources
Revisions & corrections (1)
— Official immutable release provides evidence-complete multi-agent UI attribution, nested closure and parallel snapshot fixes with explicit defaults and limitations.