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

# W&B Weave

> Send traces to W&B Weave

[Weights & Biases Weave](https://wandb.ai/site/weave) is an observability platform for tracking and evaluating LLM applications.

## Step 1: Get your W\&B API key

In W\&B, go to your [User Settings](https://wandb.ai/settings) and copy your API key.

## Step 2: Enable Broadcast in OpenRouter

Go to [Settings > Observability](https://openrouter.ai/settings/observability) and toggle **Enable Broadcast**.

![Enable Broadcast](https://mintcdn.com/openrouter-d02e98a0/PSwwwiCqAD_BNeni/assets/guides/features/broadcast/arize/broadcast-enable.png?fit=max\&auto=format\&n=PSwwwiCqAD_BNeni\&q=85\&s=a48ecd5df85b4e6f3982c8402671f631)

## Step 3: Configure W\&B Weave

Click the edit icon next to **W\&B Weave** and enter:

* **Api Key**: Your W\&B API key
* **Entity**: Your W\&B username or team name
* **Project**: The project name where traces will be logged
* **Base Url** (optional): Default is `https://trace.wandb.ai`

![W\&B Weave Configuration](https://mintcdn.com/openrouter-d02e98a0/PSwwwiCqAD_BNeni/assets/guides/features/broadcast/weave/broadcast-weave-config.png?fit=max\&auto=format\&n=PSwwwiCqAD_BNeni\&q=85\&s=227008d3e015dd7d20c6078230a3a12a)

## Step 4: Test and save

Click **Test Connection** to verify the setup. The configuration only saves if the test passes.

![W\&B Weave Configured](https://mintcdn.com/openrouter-d02e98a0/PSwwwiCqAD_BNeni/assets/guides/features/broadcast/weave/broadcast-weave-configured.png?fit=max\&auto=format\&n=PSwwwiCqAD_BNeni\&q=85\&s=7682bbb7d3e5256aff3f3082c84be586)

## Step 5: Send a test trace

Make an API request through OpenRouter and view the trace in W\&B Weave.

![W\&B Weave Trace](https://mintcdn.com/openrouter-d02e98a0/PSwwwiCqAD_BNeni/assets/guides/features/broadcast/weave/broadcast-weave-trace.png?fit=max\&auto=format\&n=PSwwwiCqAD_BNeni\&q=85\&s=95b0964189a2d422d6b2aadd731b6a16)

## Custom Metadata

W\&B Weave supports custom attributes and structured inputs for organizing and analyzing your LLM calls.

### Supported Metadata Keys

| Key | Weave Mapping | Description |
| - | - | - |
| `trace_id` | `openrouter_trace_id` attribute | Custom trace identifier stored in attributes |
| `trace_name` | `op_name` | Custom operation name displayed in the Weave call list |
| `generation_name` | `op_name` | Name for the LLM call |

### Example

```json lines theme={null}
{
  "model": "openai/gpt-4o",
  "messages": [{ "role": "user", "content": "Write a poem about AI..." }],
  "user": "user_12345",
  "session_id": "session_abc",
  "trace": {
    "trace_name": "Creative Writing Agent",
    "prompt_template": "poem_v2",
    "experiment_name": "creative_benchmark",
    "dataset_version": "1.0.0"
  }
}
```

### Attributes and Inputs

Weave organizes trace data into:

* **Attributes**: Metadata about the call (user IDs, organization IDs, trace identifiers, custom metadata)
* **Inputs**: The actual request data including messages, model parameters (temperature, max\_tokens, etc.)
* **Summary**: Token usage, costs, and timing metrics

### Additional Context

* The `user` field maps to `user_id` in attributes
* The `session_id` field maps to `session_id` in attributes
* Custom metadata keys from `trace` are merged into the call's attributes
* Model parameters (temperature, max\_tokens, top\_p) are included in inputs for easy filtering

## Privacy Mode

When [Privacy Mode](https://openrouter.ai/docs/guides/features/broadcast#privacy-mode) is enabled for this destination, prompt and completion content and provider error text are excluded from traces. All other trace data (token usage, costs, timing, model information, and custom metadata) is still sent normally. See [Privacy Mode](https://openrouter.ai/docs/guides/features/broadcast#privacy-mode) for details.