Lifecycle hooks

Set OnEvent on RunOptions or ContinueOptions to receive structured lifecycle events without coupling your application to the model transport.

result, err := agent.Run(ctx, phaseoagent.RunOptions{
  Input: prompt,
  Client: client,
  OnEvent: func(event phaseoagent.AgentEvent) {
    logger.Info("agent event",
      "type", event.Type,
      "run_id", event.RunID,
      "details", event.Details,
    )
  },
})

Useful event families include run start/completion/failure, model attempts, output text and reasoning deltas, tool start/progress/completion/failure, and human checkpoints. Keep handlers fast and non-blocking. Send events to your own queue or telemetry layer when persistence may take time, and redact sensitive tool inputs before forwarding them externally.

Last modified on July 26, 2026

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