AGUI601

Severity: error · Group: Subagents · Checked in: core · Since: 0.x

Message: SUBAGENT_STARTED reuses subagentRunId '{subagentRunId}', which is already in use this run

Spec grounding

a subagent is not started twice within a run

Source: https://docs.ag-ui.com/concepts/subagents#rules-clients-enforce

Example

A violating stream from the corpus (spec/fixtures/invalid/AGUI601-duplicate-subagent-started):

{"type":"RUN_STARTED","threadId":"thread_001","runId":"run_001","timestamp":1755300019000}
{"type":"SUBAGENT_STARTED","subagentRunId":"sub_001","name":"researcher","timestamp":1755300019100}
{"type":"SUBAGENT_STARTED","subagentRunId":"sub_001","name":"researcher","timestamp":1755300019200}
{"type":"SUBAGENT_FINISHED","subagentRunId":"sub_001","timestamp":1755300019300}
{"type":"RUN_FINISHED","threadId":"thread_001","runId":"run_001","outcome":{"type":"success"},"timestamp":1755300019400}

Expected findings:

• error AGUI601 at event 2 — SUBAGENT_STARTED reuses subagentRunId 'sub_001', which is already in use this run