AGUI103

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

Message: TEXT_MESSAGE_START messageId '{messageId}' never ended

Spec grounding

A message begins with a TextMessageStart event, followed by one or more TextMessageContent events that deliver chunks of text as they become available, and concludes with a TextMessageEnd event.

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

Example

A violating stream from the corpus (spec/fixtures/invalid/AGUI103-message-unterminated):

{"type":"RUN_STARTED","threadId":"thread_001","runId":"run_001","timestamp":1755300011000}
{"type":"TEXT_MESSAGE_START","messageId":"msg_001","role":"assistant","timestamp":1755300011100}
{"type":"TEXT_MESSAGE_CONTENT","messageId":"msg_001","delta":"never ends","timestamp":1755300011200}
{"type":"RUN_FINISHED","threadId":"thread_001","runId":"run_001","outcome":{"type":"success"},"timestamp":1755300011300}

Expected findings:

• error AGUI103 at event 3 — TEXT_MESSAGE_START messageId 'msg_001' never ended