knife4j-mcp

MCP server for Knife4j OpenAPI documentation.

This project provides a Model Context Protocol (MCP) server that converts OpenAPI documentation to Markdown format with built-in tolerant parsing, making it easily accessible to LLMs for batch operations and comprehensive API exploration.

Features

• Built-in Tolerant Parsing: Uses openapi2markdown with automatic error recovery

• Batch Query Support: Query multiple modules and APIs in single requests

• Thread-Safe Architecture: Concurrent request handling with lazy initialization

• Multiple Documentation Sources: Support for comma-separated OpenAPI URLs

• Unified Output Format: Consistent response structure with partial success handling

• Type-Safe Implementation: Full TypeScript support with proper interfaces

• Fuzzy One-shot Search: query_api powered by Fuse.js for fast discovery

Related MCP server: openapi-mcp-proxy

Usage

JSON config

{
  "mcpServers": {
    "knife4j": {
      "command": "npx",
      "args": ["-y", "knife4j-mcp"],
      "env": {
        "DOCS_URL": "http://<your-knife4j-host>/v3/api-docs,http://<your-knife4j-host>/v2/api-docs"
      }
    }
  }
}

Server Modes

Default (stdio mode): For MCP client integration

npx knife4j-mcp

SSE Mode: For HTTP-based access

npx knife4j-mcp --sse

Server runs on port 3000 (or PORT env var) with endpoints:

• /sse - Server-Sent Events transport

• /messages - POST message handling

Tools & When To Use

Choose the smallest tool that fits the job. All responses use stable markers for easy parsing.

1) query_api — one-shot fuzzy search

• Use when: you're unsure of exact names and want search + optional full view.

• Matches: Module::API, GET /path, or fuzzy keywords.

• Modes: auto (default, show full when exactly one match), summary (always list), full (always show first match details).

• Params: { q: string, mode?: 'auto'|'summary'|'full', limit?: number }

Examples:

// Fuzzy search, summary list
query_api({ q: "user list", limit: 5 })

// Exact match by method+path, return full details
query_api({ q: "GET /users/{id}", mode: "full" })

// Module::API direct lookup
query_api({ q: "UserService::ListUsers" })

2) list_modules — overview first

• Use when: you need a top-level map before drilling down.

• Params: none

• Output markers: [docs list start] ... [docs list end]

3) list_apis — enumerate APIs in known modules

• Use when: module names are known and you need candidates.

• Params: { module_names: string[] }

Examples:

list_apis({ module_names: ["UserModule"] })
list_apis({ module_names: ["UserModule", "ProductModule", "OrderModule"] })

• Output markers: [multi-module apis start] ... [multi-module apis end] (including [not found modules])

4) show_api — render full Markdown for known APIs

• Use when: you already know exact module+API names.

• Params: { api_queries: { module_name, api_name }[] }

Examples:

show_api({
  api_queries: [{ module_name: "UserModule", api_name: "Create User" }],
})
show_api({
  api_queries: [
    { module_name: "UserModule", api_name: "Create User" },
    { module_name: "ProductModule", api_name: "Get Product" },
  ],
})

• Output markers: [multi-api details start] ... [multi-api details end] (including [not found apis])

Batch Query Benefits

• Reduced Network Overhead: Query multiple resources in single request

• Partial Success Handling: Returns found results even if some items are missing

• Consistent Interface: All tools follow the same array-based input pattern

• Better Performance: Eliminates need for multiple sequential MCP calls

Development

# Install dependencies
bun install

# Build the project
bun run build

# Type checking
npx tsc --noEmit

# Run the server directly
bun run index.ts

# Run in SSE mode for testing
bun run index.ts --sse

Architecture

• Single-file MCP Server: Complete implementation in index.ts

• DocsManager Class: Thread-safe document state management with batch query methods

• Simplified Parsing: Relies on openapi2markdown built-in tolerant parsing

• Utility Functions: Unified section parsing and error handling

• Environment Configuration: DOCS_URL for OpenAPI source URLs

Migration from Single Query

If you were using the previous single-query format, update your calls:

// Old format (no longer supported)
list_apis({ module_name: "UserModule" })
show_api({ module_name: "UserModule", api_name: "Create User" })

// New format (array-based)
list_apis({ module_names: ["UserModule"] })
show_api({
  api_queries: [{ module_name: "UserModule", api_name: "Create User" }],
})

License

MIT