> ## Documentation Index
> Fetch the complete documentation index at: https://vijil-mintlify-a91c9b66.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# MCP Servers

> Wrap third-party MCP tool servers with Dome Guardrails.

<Tip>
  **TL;DR:** `DomedMCPServer` proxies a Model Context Protocol (MCP) tool server and runs Dome [Guardrails](/concepts/defense/guardrail) on every tool call. Build it with your server config and a `Dome` instance, `await` its `initialize()`, then `run()` it.
</Tip>

<Note>
  This page is about **protecting third-party MCP tool servers** your [Agent](/owner-guide/register-agents/what-is-an-agent) connects to. It is not the same as Vijil's own [Console MCP server](/developer-guide/agentic/mcp), which lets an assistant drive the Vijil Console. That server is documented separately.
</Note>

Install the MCP extra:

```bash theme={null}
pip install "vijil-dome[mcp]"
```

## Wrapping an MCP Server

`DomedMCPServer` builds a FastMCP proxy in front of your MCP server and inserts input and output Guard middleware around each tool call.

<CodeGroup>
  ```python title="Python" icon="python" theme={null}
  import asyncio
  from vijil_dome import Dome
  from vijil_dome.integrations.mcp.wrapper import DomedMCPServer

  config = {
      "mcpServers": {
          "jokes": {"command": "python", "args": ["jokes_server.py"]},
      }
  }

  dome = Dome()
  domed_server = DomedMCPServer(config, dome)

  asyncio.run(domed_server.initialize())   # required before run()
  domed_server.run(transport="http", host="0.0.0.0", port=8080)
  # or domed_server.run() for stdio
  ```
</CodeGroup>

`initialize()` builds the proxy and must be called before `run()`. Supported transports are `stdio`, `http`, `sse`, and `streamable-http`. `DomedMCPServer` accepts optional `server_name`, `tool_call_input_block_message`, `tool_call_output_block_message`, and `enforce` (default `True`).

<Note>
  Input Guards protect the wrapped server from malicious content coming *in* with a tool call. Output Guards protect the downstream Agent from malicious content coming *out* of the tool. Place prompt-injection Guards in your output Guards, since injected instructions typically arrive in tool results.
</Note>

When a tool call is flagged in `enforce` mode, the proxy returns a schema-valid placeholder result marked with `blocked_by_guardrails=True` and a `guardrail_message`, instead of the real tool output.

## Secure Proxies with Obot

<Accordion title="Advanced: place a secure gateway in front of your servers" icon="network">
  To route your servers through a secure MCP *gateway*, use `ObotClient` to generate a gateway config, then wrap it with Dome. This requires an Obot deployment.

  ```python theme={null}
  import asyncio
  from vijil_dome import Dome
  from vijil_dome.integrations.mcp import DomedMCPServer
  from vijil_dome.integrations.mcp.obot import ObotClient

  obot_client = ObotClient("<your-obot-url>", "<your-obot-token>")
  secure_config = obot_client.create_secure_mcp_config(config)

  dome = Dome()
  domed_server = DomedMCPServer(secure_config, dome)
  asyncio.run(domed_server.initialize())
  domed_server.run()
  ```

  `create_secure_mcp_config()` takes a `{"mcpServers": {...}}` config and returns a new one whose entries route through Obot connect URLs over the `streamable_http` transport.
</Accordion>

## Next Steps

<CardGroup cols={2}>
  <Card title="Configure Guardrails" icon="sliders-horizontal" href="/developer-guide/protect/configuring-guardrails">
    Choose which Guards run on tool calls
  </Card>

  <Card title="Console MCP Server" icon="server" href="/developer-guide/agentic/mcp">
    Drive the Vijil Console from an assistant
  </Card>
</CardGroup>