# Reflect and Retry plugin for ADK

Supported in ADKPython v1.16.0Go v0.5.0

The Reflect and Retry plugin can help your agent recover from error responses from ADK [Tools](/tools-custom/) and automatically retry the tool request. This plugin intercepts tool failures, provides structured guidance to the AI model for reflection and correction, and retries the operation up to a configurable limit. This plugin can help you build more resilience into your agent workflows, including the following capabilities:

- **Concurrency safe**: Uses locking to safely handle parallel tool executions.
- **Configurable scope**: Tracks failures per-invocation (default) or globally.
- **Granular tracking**: Failure counts are tracked per-tool.
- **Custom error extraction**: Supports detecting errors in normal tool responses.

## Add Reflect and Retry Plugin

Add this plugin to your ADK workflow by adding it to the plugins setting of your ADK project's App object, as shown below:

```python
from google.adk.apps.app import App
from google.adk.plugins import ReflectAndRetryToolPlugin

app = App(
    name="my_app",
    root_agent=root_agent,
    plugins=[
        ReflectAndRetryToolPlugin(max_retries=3),
    ],
)
```

```go
import (
    "google.golang.org/adk/v2/plugin/retryandreflect"
    "google.golang.org/adk/v2/runner"
)

// ... create rootAgent and sessionService ...

r, err := runner.New(runner.Config{
    AppName:        "my_app",
    Agent:          rootAgent,
    SessionService: sessionService,
    PluginConfig: runner.PluginConfig{
        Plugins: []*plugin.Plugin{
            retryandreflect.MustNew(retryandreflect.WithMaxRetries(3)),
        },
    },
})
```

With this configuration, if any tool called by an agent returns an error, the request is updated and tried again, up to a maximum of 3 attempts, per tool.

## Configuration settings

The Reflect and Retry Plugin has the following configuration options:

- **`max_retries`**: (optional) Total number of additional attempts the system makes to receive a non-error response. Default value is 3.
- **`throw_exception_if_retry_exceeded`**: (optional) If set to `False`, the system does not raise an error if the final retry attempt fails. Default value is `True`.
- **`tracking_scope`**: (optional)
  - **`TrackingScope.INVOCATION`**: Track tool failures across a single invocation and user. This value is the default.
  - **`TrackingScope.GLOBAL`**: Track tool failures across all invocations and all users.

### Advanced configuration

You can further modify the behavior of this plugin by extending the `ReflectAndRetryToolPlugin` class. The following code sample demonstrates a simple extension of the behavior by selecting responses with an error status:

```python
class CustomRetryPlugin(ReflectAndRetryToolPlugin):
  async def extract_error_from_result(self, *, tool, tool_args,tool_context,
  result):
    # Detect error based on response content
    if result.get('status') == 'error':
        return result
    return None  # No error detected

# add this modified plugin to your App object:
error_handling_plugin = CustomRetryPlugin(max_retries=5)
```

## Next steps

For complete code samples using the Reflect and Retry plugin, see the following:

- [Basic](https://github.com/google/adk-python/tree/main/contributing/samples/plugin/plugin_reflect_tool_retry/basic) code sample
- [Hallucinating function name](https://github.com/google/adk-python/tree/main/contributing/samples/plugin/plugin_reflect_tool_retry/hallucinating_func_name) code sample