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

# MCP servers

> Let a run's agent use MCP servers, including ones that need your account

A run's agent can call MCP servers. It reaches them through Tracks, never directly: credentials never enter the sandbox.

## Servers open to anyone

Give the server's URL when you start the run. Tracks calls it without credentials, or with fixed headers you set, such as an API key. Header values never enter the sandbox and are never returned.

```bash theme={null}
tracks runs create "Summarize the docs" --harness claude-code --model claude-sonnet-5-5 \
  --mcp docs=https://example.com/mcp \
  --mcp-header 'docs=Authorization: Bearer KEY'
```

## Servers that need your account

Services such as Linear, Notion or GitHub need you to sign in. Connect each one once, then reuse the connection in every run:

**1. Connect**

```bash theme={null}
tracks connections create https://mcp.linear.app/mcp
```

Your browser opens to sign in and consent. The command prints the connection once it is `active`.

**2. Use it in a run**

```bash theme={null}
tracks runs create "Triage my open issues" --harness claude-code --model claude-sonnet-5-5 \
  --mcp linear=<connection-id>
```

The agent calls the server as you.

`tracks connections list` shows your connections and their status. Deleting a connection deletes the access it holds.

## Servers that filter callers

Requests to MCP servers come from a fixed set of addresses, listed at `https://tracks.alpic.ai/api/egress-ips`. Allow them on a server that only accepts known callers.

## In experiments

Experiments pick MCP servers from your organization's library instead: add them in the web app, under **Library** → **MCP servers**. See [Measure your MCP server or skill](https://docs.tracks.alpic.ai/guides/measure-your-mcp-server.md).


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