MCP (Model Context Protocol)

Nexrall Code connects to external tools and data sources through the Model Context Protocol — an open standard for giving an agent access to servers that expose tools, resources, and prompts. An MCP server is a small program (or remote endpoint) the agent can call; wiring one in is how you let the agent read your design docs, update tickets, or query an internal API.

Transport support

Nexrall Code's MCP client speaks two transports:

Transport	Use when
SSE (sse)	The server is a remote HTTP endpoint that streams events over Server-Sent Events.
HTTP (http)	The server is a plain HTTP JSON-RPC endpoint (stateless request/response).

Both are configured the same way in .nexrall/mcp.json.

Configuring a server

Add servers to .nexrall/mcp.json (project) or ~/.nexrall/mcp.json (user-level). Each entry names the server and tells the client how to reach it:

{
  "mcpServers": {
    "github": {
      "transport": "http",
      "url": "https://mcp.example.com/github"
    },
    "local-tools": {
      "transport": "sse",
      "url": "https://mcp.example.com/sse"
    }
  }
}

The exact fields follow the server's transport (a url for remote HTTP/SSE servers). Locally-spawned servers and other transports are configured with their own fields — see your server's documentation for its required shape.

Using MCP tools

Once configured and connected, the server's tools become available to the agent alongside its built-in tools. Tools from a server are typically namespaced so they don't collide with built-ins. Whether a given MCP tool runs automatically or prompts for approval is governed by the same permission rules as everything else.

Security

MCP servers run code on your behalf, so Nexrall treats them as a trust boundary:

• Plugins that ship MCP config require explicit confirmation before install — this can't be bypassed with --yes, because an MCP server can execute arbitrary commands as part of your sessions (see Plugins).
• Configure servers you don't fully trust with ask rules so each call is reviewed before it runs.

Next steps

• Configuration — the .nexrall/ directory where mcp.json lives.
• Plugins — how MCP config is bundled and merged from installed plugins.
• Agent SDK — McpManager in the npm package, for connecting MCP servers programmatically.