# FiddlerInstrumentationHook

Centralized instrumentation hook for Strands agents with Fiddler integration.

This hook provider automatically captures telemetry data from Strands agents and enriches OpenTelemetry spans with Fiddler-specific attributes. It handles three key events: before invocation, after tool execution, and after model calls.

The hook is automatically injected when using StrandsAgentInstrumentor, so users typically don't need to manually add it to their agents.

## Example

```python
from strands import Agent
from fiddler_strandsagents import FiddlerInstrumentationHook

# Manual usage (not needed with StrandsAgentInstrumentor)
agent = Agent(
    model=model,
    system_prompt="...",
    hooks=[FiddlerInstrumentationHook()]
)
```

## register\_hooks()

Register hook callbacks with the Strands agent registry.

This method is called by the Strands framework to register callbacks for various agent lifecycle events.

## Parameters

| Parameter  | Type           | Required | Default | Description                                 |
| ---------- | -------------- | -------- | ------- | ------------------------------------------- |
| `registry` | `HookRegistry` | ✗        | `None`  | The HookRegistry to register callbacks with |

## tool\_end()

Handle the completion of a tool invocation.

Enriches the current OpenTelemetry span with custom attributes that were set on the tool using set\_span\_attributes(). Attributes are prefixed with 'fiddler.span.user.' for namespacing.

## Parameters

| Parameter | Type                 | Required | Default | Description                                                |
| --------- | -------------------- | -------- | ------- | ---------------------------------------------------------- |
| `event`   | `AfterToolCallEvent` | ✗        | `None`  | AfterToolInvocationEvent containing tool execution details |

## model\_end()

Handle the completion of a model invocation.

Enriches the current OpenTelemetry span with custom attributes that were set on the model using set\_span\_attributes(). Attributes are prefixed with 'fiddler.span.user.' for namespacing.

## Parameters

| Parameter | Type                  | Required | Default | Description                                                  |
| --------- | --------------------- | -------- | ------- | ------------------------------------------------------------ |
| `event`   | `AfterModelCallEvent` | ✗        | `None`  | AfterModelInvocationEvent containing model execution details |

## before\_invocation()

Handle the start of an agent invocation.

Enriches the current OpenTelemetry span with conversation ID and session attributes that were set using set\_conversation\_id() and set\_session\_attributes(). This ensures trace-level context is available for all child spans.

## Parameters

| Parameter | Type                    | Required | Default | Description                                               |
| --------- | ----------------------- | -------- | ------- | --------------------------------------------------------- |
| `event`   | `BeforeInvocationEvent` | ✗        | `None`  | BeforeInvocationEvent containing agent invocation details |