AGUI104

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

Message: messageId '{messageId}' was already used by a completed message

Spec grounding

It establishes a unique messageId that will be referenced by subsequent content chunks and the end event.

Source: https://docs.ag-ui.com/concepts/events#textmessagestart

Example

A violating stream from the corpus (spec/fixtures/invalid/AGUI104-duplicate-message-id):

{"type":"RUN_STARTED","threadId":"thread_001","runId":"run_001","timestamp":1755300011400}
{"type":"TEXT_MESSAGE_START","messageId":"msg_001","role":"assistant","timestamp":1755300011500}
{"type":"TEXT_MESSAGE_CONTENT","messageId":"msg_001","delta":"first use","timestamp":1755300011600}
{"type":"TEXT_MESSAGE_END","messageId":"msg_001","timestamp":1755300011700}
{"type":"TEXT_MESSAGE_START","messageId":"msg_001","role":"assistant","timestamp":1755300011800}
{"type":"RUN_FINISHED","threadId":"thread_001","runId":"run_001","outcome":{"type":"success"},"timestamp":1755300011900}

Expected findings:

• error AGUI104 at event 4 — messageId 'msg_001' was already used by a completed message