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

# Errors

> Error structure and handling in the Agent Communication Protocol

The **Agent Communication Protocol (ACP)** provides a consistent error structure to make error handling easier for both clients and servers.

## Error structure

Each error contains:

* **Code**: A predefined identifier for programmatic handling
* **Message**: A human-readable description for display or logging

Use codes to drive error-handling logic and messages for user display or logging. See the [specification](https://github.com/i-am-bee/acp/blob/main/docs/spec/openapi.yaml) for the current set of error codes.

## Error handling

Servers can send errors in three ways:

* HTTP response body (failed requests)
* Within a failed run
* As events in a stream error

Clients must monitor all these locations and handle errors appropriately.

SDK clients should expose errors in a way that's natural for the programming language, typically as exceptions:

<Tabs>
  <Tab title="Python">
    ```python theme={null}
    try:
        run = await client.run_sync(...)
        run.raise_for_status()
    except ACPError as e:
        error = e.error
        # Logic that handles the error
    ```
  </Tab>
</Tabs>

### Guidance

When handling errors:

* Use the **code** for programmatic decisions
* Use the **message** for display or logging
* Tailor your response to your application type

**Example**: A chat UI should show invalid\_input error messages to users, but log server\_error messages to the console (since they may be too technical). A CLI would likely display all error messages regardless of code.