Tools: Model Context Protocol (mcp)

Lectic can act as a client for servers that implement the Model Context Protocol (MCP). This allows you to connect your LLM to a vast and growing ecosystem of pre-built tools and services.

You can find lists of available servers here: - Official MCP Server List - Awesome MCP Servers

Configuration

Note: The snippets below show only the tool definition. They assume you have an interlocutor with a valid prompt and model configuration. See Getting Started for a full header example.

You can connect to an MCP server in three ways: by running a local server as a command, or by connecting to a remote server over WebSockets or SSE.

Local MCP Server (mcp_command)

This is the most common way to run an MCP server. You provide the command to start the server, and Lectic manages its lifecycle.

tools:
  - name: brave
    mcp_command: npx
    args:
      - "-y"
      - "@modelcontextprotocol/server-brave-search"
    env:
      BRAVE_API_KEY: "your_key_here"
    roots:
      - /home/user/research-docs/

Local MCP servers are started on demand for the active interlocutor and managed by Lectic for the duration of the session.

Remote MCP Servers

You can also connect to running MCP servers.

• mcp_ws: The URL for a remote server using a WebSocket connection.
• mcp_sse: The URL for a remote server using Server-Sent Events.
• mcp_shttp: The URL for a remote server using Streamable HTTP.

For example:

tools:
  - name: documentation_search 
    mcp_shttp: https://mcp.context7.com/mcp

Server Resources and Content References

If you give an MCP tool a name (e.g., name: brave), you can access any resources it provides using a special content reference syntax. The scheme is the server’s name plus the resource type.

For example, to access a repo resource from a server named github: [README](github+repo://gleachkr/Lectic/contents/README.md)

The LLM is also given a tool to list the available resources from the server.

Excluding server tools

You can hide specific tools that a server exposes by listing their names under exclude.

tools:
  - name: github
    mcp_ws: wss://example.org/mcp
    exclude:
      - dangerous_tool
      - low_value_tool

Safety and trust

Warning

While powerful, the MCP protocol carries significant security risks. Treat MCP integration as a high-trust capability. Never connect to untrusted servers; a malicious server could exfiltrate data or perform unwanted actions. Lectic’s safety mechanisms reduce mistakes from a well‑behaved LLM, not attacks from a hostile server.

Confirmation via hooks

Just like with the exec tool, you can use the tool_use_pre hook to implement confirmation dialogs or logic. See Hooks for examples.

Sandboxing (sandbox)

For local mcp_command tools, you can specify a sandbox script. This script will be used to launch the MCP server process in a controlled and isolated environment, limiting its access to your system.

See the documentation for the Exec Tool for more details on how sandboxing scripts work.