MCP 三大原语：Tools、Resources、Prompts

// 请求
{ "jsonrpc": "2.0", "id": 1, "method": "tools/list" }

// 响应
{
  "jsonrpc": "2.0", "id": 1,
  "result": {
    "tools": [{
      "name": "get_weather",
      "title": "Weather Information Provider",
      "description": "Get current weather for a location",
      "inputSchema": {
        "type": "object",
        "properties": {
          "location": { "type": "string", "description": "City name or zip code" }
        },
        "required": ["location"]
      }
    }]
  }
}

// 请求
{
  "jsonrpc": "2.0", "id": 2,
  "method": "tools/call",
  "params": { "name": "get_weather", "arguments": { "location": "Beijing" } }
}

// 响应
{
  "jsonrpc": "2.0", "id": 2,
  "result": {
    "content": [{ "type": "text", "text": "北京当前：28°C，晴，东风 3 级" }],
    "isError": false
  }
}

// 请求
{ "jsonrpc": "2.0", "id": 1, "method": "resources/list" }

// 响应
{
  "jsonrpc": "2.0", "id": 1,
  "result": {
    "resources": [{
      "uri": "file:///project/src/main.rs",
      "name": "main.rs",
      "title": "Rust Application Main File",
      "description": "Primary application entry point",
      "mimeType": "text/x-rust"
    }]
  }
}

// 请求
{
  "jsonrpc": "2.0", "id": 2,
  "method": "resources/read",
  "params": { "uri": "file:///project/src/main.rs" }
}

// 响应
{
  "jsonrpc": "2.0", "id": 2,
  "result": {
    "contents": [{
      "uri": "file:///project/src/main.rs",
      "mimeType": "text/x-rust",
      "text": "fn main() {\n    println!(\"Hello world!\");\n}"
    }]
  }
}

// 请求
{ "jsonrpc": "2.0", "id": 1, "method": "prompts/list" }

// 响应
{
  "jsonrpc": "2.0", "id": 1,
  "result": {
    "prompts": [{
      "name": "code_review",
      "title": "Request Code Review",
      "description": "Asks the LLM to analyze code quality and suggest improvements",
      "arguments": [
        { "name": "code", "description": "The code to review", "required": true }
      ]
    }]
  }
}

// 请求
{
  "jsonrpc": "2.0", "id": 2,
  "method": "prompts/get",
  "params": {
    "name": "code_review",
    "arguments": { "code": "def hello():\n    print('world')" }
  }
}

// 响应
{
  "jsonrpc": "2.0", "id": 2,
  "result": {
    "description": "Code review prompt",
    "messages": [{
      "role": "user",
      "content": {
        "type": "text",
        "text": "Please review this Python code:\ndef hello():\n    print('world')"
      }
    }]
  }
}

from mcp.server.fastmcp import FastMCP

mcp = FastMCP("project-assistant")

# ---------- Tool：执行代码格式化（有副作用） ----------
@mcp.tool()
def format_code(code: str, language: str = "python") -> str:
    """Format code using standard style guidelines"""
    # 实际实现里会调用 black / prettier 等工具
    return f"Formatted {language} code:\n{code.strip()}"

# ---------- Resource：提供项目 README（只读） ----------
@mcp.resource("file:///project/README.md")
def get_readme() -> str:
    """Project README file"""
    with open("/project/README.md") as f:
        return f.read()

# ---------- Prompt：代码评审模板（用户手动触发） ----------
@mcp.prompt()
def code_review(code: str) -> str:
    """Ask the LLM to review code quality"""
    return f"""Please review the following code for:
1. Code quality and readability
2. Potential bugs
3. Performance issues
4. Security concerns

Code:
{code}"""

if __name__ == "__main__":
    mcp.run()