> ## Documentation Index
> Fetch the complete documentation index at: https://e2b.manicule.dev/llms.txt
> Use this file to discover all available pages before exploring further.
> For every page in one file, fetch https://e2b.manicule.dev/llms-full.txt (large).
> To search and read these docs as tools, connect the MCP server at https://e2b.manicule.dev/api/mcp.
> Every agent surface: https://e2b.manicule.dev/.well-known/llms-manifest.json

# Custom servers (/docs/mcp/custom-servers)

<!-- agent-signals: reading_time_min: 1 · est_tokens: 547 · updated: 2026-07-30 -->
Related: [Available servers](/docs/mcp/available-servers.md), [Custom templates](/docs/mcp/custom-templates.md), [Examples](/docs/mcp/examples.md), [Quickstart](/docs/mcp/quickstart.md)

> Use custom MCP servers from GitHub repositories

In addition to the 200+ pre-built MCP servers from the [Docker MCP Catalog](https://hub.docker.com/mcp), you can run custom MCP servers directly from public GitHub repositories.

## How it works

When you specify a GitHub repository, E2B will:

1. Clone the repository into the sandbox
2. Run the `installCmd` (optional) to install dependencies
3. Run the `runCmd` to start the MCP server with stdio transport

The `runCmd` must start an MCP server that follows the [MCP specification](https://modelcontextprotocol.io/specification/2025-06-18) and communicates via stdio (standard input/output).

## Using a custom MCP server

<CodeGroup>
```typescript title="TypeScript"
import Sandbox from 'e2b'

const sandbox = await Sandbox.create({
    mcp: {
        'github/modelcontextprotocol/servers': {
            installCmd: 'npm install',
            runCmd: 'sudo npx -y @modelcontextprotocol/server-filesystem /root',
        },
    },
});
```

```python title="Python"
from e2b import Sandbox
import os

sbx = Sandbox.create(
    mcp={
        "github/modelcontextprotocol/servers": {
                "install_cmd": "npm install",
                "run_cmd": "sudo npx -y @modelcontextprotocol/server-filesystem /root",
        },
    }
)
```
</CodeGroup>

## Configuration

<ParamField path="installCmd" type="string">Optional command to run before starting the MCP server. Use this to install dependencies (e.g., `npm install`, `pip install -r requirements.txt`).</ParamField>

<ParamField path="runCmd" type="string" required>Command to start the MCP server. Must launch a stdio-enabled MCP server.</ParamField>

<Note>**Important for npx-based servers:** Always include `installCmd: 'npm install'` (or equivalent) when using `npx` in your `runCmd`. Without installing dependencies first, npx will try to use the local repository and fail.</Note>

## Troubleshooting

If your custom MCP server doesn't work as expected:

1. Explore the sandbox either via the [dashboard](https://e2b.dev/dashboard) or by connecting to it via `e2b connect <sandbox-id>`
2. Check the gateway log file with `sudo cat /var/log/mcp-gateway/gateway.log`.