> ## Documentation Index
> Fetch the complete documentation index at: https://phaseo.app/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Errors and troubleshooting

> Handle model, tool, validation, cancellation, and continuation failures in Go agents.

Agent failures normally come from the model request, a local tool, schema validation, cancellation, or an incomplete human decision. Keep these paths visible in logs and return safe errors to callers.

## Recover from tool errors

Set `OnError: "return-to-model"` on a tool when the model can reasonably recover from the failure. The SDK converts the error into a tool result and allows the next turn to choose another action. Leave the default fail-run behavior for unsafe or unrecoverable failures.

## Respect cancellation

Pass the request context to `Run`, `Continue`, or `Stream`. Cancelling it stops model streaming and prevents new tool work from starting.

```go theme={null}
ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
defer cancel()

result, err := agent.Run(ctx, options)
if errors.Is(err, context.DeadlineExceeded) {
  // Persist enough application state to retry or report the timeout.
}
```

## Diagnose continuation errors

When a run is waiting for a person, every pending call needs an approval, rejection, or externally supplied result keyed by its tool-call ID. Persist the entire returned run record; a human message alone is not a substitute for those decisions.

## Capture useful context

Record the run ID, step index, request ID, provider, model, finish reason, tool-call ID, and stop reason. Lifecycle hooks and DevTools expose these fields without requiring transport-level logging.