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

# Resources

> Expose read-only data to AI agents via MCP

Resources expose **read-only data** to MCP clients. Unlike tools (which perform actions), resources provide context:database schemas, config files, documentation, or any data the LLM needs to make better decisions.

## Defining Resources

```python theme={null}
from concierge import Concierge

app = Concierge("my-server")

@app.resource("resource://app/settings")
def get_settings() -> str:
    """Current application settings."""
    return json.dumps({
        "max_cart_items": 50,
        "supported_currencies": ["USD", "EUR", "GBP"],
        "free_shipping_threshold": 100,
    })
```

The resource URI (`resource://app/settings`) is how clients reference this resource. For ChatGPT widget apps, use the `ui://` scheme (e.g. `ui://widget/my-widget`).

## Resource Templates

Use URI templates for dynamic resources:

```python theme={null}
@app.resource("resource://products/{product_id}")
def get_product_docs(product_id: str) -> str:
    """Product documentation and specifications."""
    # Replace with your own data source
    return f"# Product {product_id}\n\nA great product.\n\nPrice: $99"
```

## When to Use Resources vs Tools

| Use Case             | Resource | Tool |
| -------------------- | -------- | ---- |
| Read-only data       | Yes      | No   |
| Database schema      | Yes      | No   |
| Configuration        | Yes      | No   |
| Search/query         | No       | Yes  |
| Create/update/delete | No       | Yes  |
| Side effects         | No       | Yes  |

<Tip>
  Resources are fetched **once** at the start of a conversation and cached. Use them for stable context that doesn't change per-request.
</Tip>

## Resources with Stages

Resources can be scoped to stages, just like tools. This means the LLM only sees resources relevant to the current workflow step.