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

# Authentication

> Authenticate the NeetoCal MCP server with your API key.

The MCP server authenticates with the same API key as the [REST API](/getting-started/authentication) — but instead of a header you set on every request, your assistant passes it as a bearer token from its MCP config.

## Generating an API key

You need a NeetoCal API key before you can connect an assistant. [Learn how to generate your API key here.](https://help.neetocal.com/articles/api-keys)

## How MCP authenticates

NeetoCal runs a hosted MCP server at `https://connect.neetocal.com/mcp/messages`. Your assistant sends the API key on every request in an `Authorization` header:

```http theme={"system"}
Authorization: Bearer <your-api-key>
```

You set this once in your assistant's MCP config — see [Connect](/mcp/connect) for the exact file and format for each assistant. Paste your key in place of `YOUR_API_KEY`, and the assistant sends the header from then on.

Each NeetoCal surface authenticates differently:

|              | How you authenticate                                                |
| ------------ | ------------------------------------------------------------------- |
| **REST API** | `X-Api-Key` header on every request                                 |
| **CLI**      | Sign in through your browser; credentials are stored locally        |
| **MCP**      | `Authorization: Bearer <your-api-key>` from your assistant's config |

## Keep your key safe

<Tip>
  Treat your API key like a password. Generate a separate key per workspace — a key from one workspace won't work in another.
</Tip>

<Warning>
  Your API key grants access to your workspace's scheduling data. Anyone who can read your assistant's config can use it, so don't commit it to shared repositories or paste it where others can see it.
</Warning>

## When authentication fails

MCP doesn't surface a 401 the way a raw API call does. A missing or invalid key shows up instead as one of these symptoms:

* The `neetocal` tools never appear in your assistant.
* A tool call fails, and the assistant reports it couldn't reach NeetoCal.

Both usually mean the `Authorization` header is wrong — a mistyped key, a key from a different workspace, or a key that's been revoked. Verify or regenerate your key from the [API Keys article](https://help.neetocal.com/articles/api-keys), then work through [Troubleshooting](/mcp/troubleshooting).