@liche/mcp-server

MCP (Model Context Protocol) server runtime extension for @liche/core CLIs.

Adds a --mcp global flag that turns the CLI into a JSON-RPC MCP server over stdio, and a /mcp HTTP route that handles MCP requests over HTTP. Commands become MCP tools according to this adapter's policy: interactive commands are hidden by default, and callers can pass tools.include / tools.exclude for explicit visibility.

import { arg, defineCli, defineCommand, z } from '@liche/core'
import { mcpServer } from '@liche/mcp-server'

defineCli({
  name: 'shipyard',
  extensions: [mcpServer({ tools: { include: ['deploy', 'status'] } })],
  commands: [
    defineCommand({
      path: ['deploy'],
      input: {
        options: z.object({
          replicas: arg.positiveInt().default(1),
        }),
      },
      run: ({ options }) => ({ replicas: options.replicas }),
    }),
  ],
})

Tool projection

The adapter projects Core command contracts to MCP tools without executing handlers. Runtime validation still flows through Core, so command failures are returned as result.isError: true with the command error envelope serialized in content[0].text.

Validation errors preserve their MCP input source:

{
  "fieldErrors": [
    {
      "path": "$.replicas",
      "source": { "kind": "extension", "transport": "mcp", "key": "replicas" }
    }
  ]
}

arg.fromString() surface policy is enforced before calls run. A CLI-only codec is excluded from tools/list, and tools/call returns JSON-RPC -32602 with data.code: "UNSUPPORTED_SURFACE" if a caller attempts to invoke it anyway. Codecs marked surface: "all" or surface: { kind: "extension", transport: "mcp" } are visible to this adapter.

Pair with @liche/mcp-installer to register the binary as an MCP server in Claude Code / Cursor config.