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

# Changes in v0.5.3

> November 14th, 2025

As Squirrels maintainers, we are dedicated in maintaining backward compatibility across all patch versions in the same minor version. We are also committed to avoid breaking changes across minor versions as much as possible. However, if absolutely necessary, we will provide a smooth upgrade path for users.

The following are fixes and new features for [v0.5.3].

## Fixes

* The `x-api-key` header was not being respected for MCP requests. This has been fixed.

## New features

**MCP resource for data catalog**

* A new MCP resource was added for the data catalog, which returns the same thing as the `get_data_catalog` tool
* Supporting MCP clients can use this resource to automatically add the data catalog to the system prompt when starting a new conversation, without needing the AI agent to call the `get_data_catalog` tool
* The resource has the following properties:
  * uri: `sqrl://data-catalog`
  * name: `data_catalog_from_[project_name]`
  * title: `Data Catalog (Project: [project_label])`
  * description: `Details of all datasets and parameters you can access in the Squirrels project '[project_name]'`

**API headers documentation**

* The API documentation was updated to include the `x-api-key` header.
* The configurable headers were intentionally left out of the documentation given that they are meant for internal use only.

**New welcome banner in terminal for API server**

* The welcome banner in the terminal after running `sqrl run` now looks something like this:

```
══════════════════════════════════════════════════
                            👋  WELCOME TO SQUIRRELS!
══════════════════════════════════════════════════

 🖥️ Application UI
  └─ Squirrels Studio: http://127.0.0.1:8000/project/expenses/v1/studio
     └─ (The following URL also redirects to studio: http://127.0.0.1:8000)

 🔌 MCP Server URLs
  ├─ Option 1:         http://127.0.0.1:8000/project/expenses/v1/mcp
  └─ Option 2:         http://127.0.0.1:8000/mcp

 📖 API Documentation
  ├─ Swagger UI:       http://127.0.0.1:8000/project/expenses/v1/docs
  ├─ ReDoc UI:         http://127.0.0.1:8000/project/expenses/v1/redoc
  └─ OpenAPI Spec:     http://127.0.0.1:8000/project/expenses/v1/openapi.json

──────────────────────────────────────────────────
                   ✨ Server is running! Press CTRL+C to stop.
──────────────────────────────────────────────────
```

## More info

For more details, see the [GitHub release notes for v0.5.3][v0.5.3].

[v0.5.3]: https://github.com/squirrels-analytics/squirrels/releases/tag/v0.5.3