Installation

The LexBuild MCP server runs locally via npx and connects to the LexBuild Data API over the network. No local database or build step is required.

Hosted Endpoint

For clients that support HTTP transport, you can connect to the hosted server with no installation:

https://mcp.lexbuild.dev/mcp

No API key is required for basic usage. The hosted endpoint is subject to the same rate limits as anonymous access. See the client-specific sections below for how to configure HTTP transport where supported.

Global Install

If you prefer a persistent installation over npx, install globally:

npm install -g @lexbuild/mcp

Then use lexbuild-mcp as the command in any client configuration below instead of npx.

Claude Desktop

Add to your Claude Desktop config file:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json

{
  "mcpServers": {
    "lexbuild": {
      "command": "npx",
      "args": ["-y", "@lexbuild/mcp"]
    }
  }
}

Restart Claude Desktop after saving. You should see “lexbuild” listed in the MCP servers panel.

Claude Code

Add to your project’s .mcp.json or global MCP config:

{
  "mcpServers": {
    "lexbuild": {
      "command": "npx",
      "args": ["-y", "@lexbuild/mcp"]
    }
  }
}

Codex CLI

Add to ~/.codex/config.toml (global) or .codex/config.toml (project):

[mcp_servers.lexbuild]
command = "npx"
args = ["-y", "@lexbuild/mcp"]

Or use the hosted endpoint:

[mcp_servers.lexbuild]
url = "https://mcp.lexbuild.dev/mcp"

[!NOTE] Codex CLI uses TOML, not JSON. For API key auth, use env = { "LEXBUILD_API_KEY" = "lxb_your_key_here" }.

Copilot CLI

Add to ~/.copilot/mcp-config.json:

{
  "mcpServers": {
    "lexbuild": {
      "type": "local",
      "command": "npx",
      "args": ["-y", "@lexbuild/mcp"]
    }
  }
}

Or use the hosted endpoint:

{
  "mcpServers": {
    "lexbuild": {
      "type": "http",
      "url": "https://mcp.lexbuild.dev/mcp"
    }
  }
}

[!NOTE] Copilot CLI requires the type field: "local" for stdio servers, "http" for remote.

Cursor

Add to your Cursor MCP settings (Settings > MCP Servers):

{
  "mcpServers": {
    "lexbuild": {
      "command": "npx",
      "args": ["-y", "@lexbuild/mcp"]
    }
  }
}

Gemini CLI

Add to ~/.gemini/settings.json (global) or .gemini/settings.json (project):

{
  "mcpServers": {
    "lexbuild": {
      "command": "npx",
      "args": ["-y", "@lexbuild/mcp"]
    }
  }
}

Or use the hosted endpoint:

{
  "mcpServers": {
    "lexbuild": {
      "httpUrl": "https://mcp.lexbuild.dev/mcp"
    }
  }
}

[!NOTE] Gemini CLI uses httpUrl (not url) for remote servers.

VS Code

Add to .vscode/mcp.json in your workspace:

{
  "servers": {
    "lexbuild": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "@lexbuild/mcp"]
    }
  }
}

[!NOTE] VS Code uses servers (not mcpServers) and requires the type field.

Warp

Open Warp Settings > AI > MCP Servers and add:

{
  "mcpServers": {
    "lexbuild": {
      "command": "npx",
      "args": ["-y", "@lexbuild/mcp"]
    }
  }
}

Warp can also auto-detect MCP servers configured for other clients (Claude Desktop, Codex, Gemini CLI) via the “File-based MCP Servers” toggle in settings.

Zed

Add to your Zed settings file (~/.config/zed/settings.json on macOS/Linux):

{
  "context_servers": {
    "lexbuild": {
      "source": "custom",
      "command": "npx",
      "args": ["-y", "@lexbuild/mcp"]
    }
  }
}

Or use the hosted endpoint:

{
  "context_servers": {
    "lexbuild": {
      "url": "https://mcp.lexbuild.dev/mcp"
    }
  }
}

[!WARNING] The "source": "custom" field is required for stdio servers in Zed. Without it, Zed silently ignores the entry. The key is context_servers, not mcpServers.

With an API Key

An API key is optional. Without one, requests use the anonymous rate limit (60 requests per minute). With a key, you get higher rate limits for sustained usage.

Add the key as an environment variable in your client config. For JSON-based clients:

{
  "env": {
    "LEXBUILD_API_KEY": "lxb_your_key_here"
  }
}

For Codex CLI (TOML):

env = { "LEXBUILD_API_KEY" = "lxb_your_key_here" }

Environment Variables

All configuration is optional. The defaults work for most setups.

These additional variables are only relevant if you are self-hosting the HTTP transport:

Verifying the Installation

After configuring your client, ask your AI assistant something like:

“Search U.S. law for the Freedom of Information Act”

If the MCP server is connected, the assistant will use the search_laws tool and return results from the U.S. Code.