Event flow sequence - Amazon Nova

Event flow sequence

A typical conversation follows this event sequence:

  1. Session Start - Initialize the conversation session

  2. System Prompt - Send system instructions

  3. Chat History (optional) - Provide conversation context

  4. Audio Chunks - Stream user audio input

  5. Completion Start - AI begins processing

  6. ASR Transcripts (USER) - User speech transcription

  7. Tool Use (optional) - AI requests tool execution

  8. Tool Handling (optional) - Process and return tool results

  9. Transcript (ASSISTANT) - SPECULATIVE - Preliminary AI response

  10. Audio Chunks - Stream AI audio output

  11. Transcript (ASSISTANT) - FINAL - Final AI response transcript

  12. Content End Audio - Marks the end of audio content

  13. Prompt End - Indicates the completion of the prompt processing

  14. Session End - Close the conversation