View and customize trace display ↗

    import weave

    # Initialize the client
    client = weave.init("your-project-name")

    # Get a specific call by its ID
    call = client.get_call("call-uuid-here")

    print(call)
    ```
  <span class="tab-end"></span>

  <span class="tab-start" data-tab-title="TypeScript"></span>
```typescript
    import * as weave from 'weave'

    // Initialize the client
    const client = await weave.init('intro-example')

    // Get a specific call by its ID
    const call = await client.getCall('call-uuid-here')

    console.log(call)
    ```
  <span class="tab-end"></span>

  <span class="tab-start" data-tab-title="HTTP API"></span>
To view a call using the Service API, make a request to the [`/call/read`](https://docs.wandb.ai/weave/reference/service-api/calls/call-read) endpoint.

```bash
    curl -L 'https://trace.wandb.ai/call/read' \
    -H 'Content-Type: application/json' \
    -H 'Accept: application/json' \
    -d '{
        "project_id": "string",
        "id": "string",
    }'
    ```
  <span class="tab-end"></span>
<span class="tab-group-end"></span>

## Customize rendered traces with `weave.Markdown`

Use `weave.Markdown` to customize how your trace information is displayed without losing the original data. This allows you to render your inputs and outputs as readable blocks of formatted content while preserving the underlying data structure.

<span class="tab-group-start"></span>
  <span class="tab-start" data-tab-title="Python"></span>
Use `postprocess_inputs` and `postprocess_output` functions in your `@weave.op` decorator to format your trace data. The following code sample uses postprocessors to render a call in Weave with emojis and more readable formatting:

```python
    import weave

    def postprocess_inputs(query) -> weave.Markdown:
        search_box = f"""
    **Search Query:**
    ``+`
    {query}
    ``+`
    """
        return {"search_box": weave.Markdown(search_box),
                "query": query}

    def postprocess_output(docs) -> weave.Markdown:
        formatted_docs = f"""
    # {docs[0]["title"]}

    {docs[0]["content"]}

    [Read more]({docs[0]["url"]})

    ---

    # {docs[1]["title"]}

    {docs[1]["content"]}

    [Read more]({docs[1]["url"]})
    """
        return weave.Markdown(formatted_docs)

    @weave.op(
        postprocess_inputs=postprocess_inputs,
        postprocess_output=postprocess_output,
    )
    def rag_step(query):
        # example newspaper articles of the companies on the S&P 500 
        docs = [
            {
                "title": "OpenAI",
                "content": "OpenAI is a company that makes AI models.",
                "url": "https://www.openai.com",
            },
            {
                "title": "Google",
                "content": "Google is a company that makes search engines.",
                "url": "https://www.google.com",
            },
        ]
        return docs

    if __name__ == "__main__":
        weave.init('markdown_renderers')
        rag_step("Tell me about OpenAI")
    ```
  <span class="tab-end"></span>

  <span class="tab-start" data-tab-title="Typescript"></span>
```plaintext
    This feature is not available in the TypeScript SDK yet.
    ```
  <span class="tab-end"></span>
<span class="tab-group-end"></span>

In the following screenshot, you can see the unformatted and formatted outputs side by side.

<img src="https://mintcdn.com/wb-21fd5541/nH7Qx1F6mfkUr7pE/weave/guides/tracking/imgs/md-call-render.png?fit=max&auto=format&n=nH7Qx1F6mfkUr7pE&q=85&s=3ab98e6b7301a33c5ae5b5d5f11ceb37" alt="A call rendered in the Weave UI using the code sample." width="1440" height="1980" data-path="weave/guides/tracking/imgs/md-call-render.png" />