为 Claude 提供自定义工具

  from typing import Any
  import httpx
  from claude_agent_sdk import tool, create_sdk_mcp_server

  # Define a tool: name, description, input schema, handler
  @tool(
      "get_temperature",
      "Get the current temperature at a location",
      {"latitude": float, "longitude": float},
  )
  async def get_temperature(args: dict[str, Any]) -> dict[str, Any]:
      async with httpx.AsyncClient() as client:
          response = await client.get(
              "https://api.open-meteo.com/v1/forecast",
              params={
                  "latitude": args["latitude"],
                  "longitude": args["longitude"],
                  "current": "temperature_2m",
                  "temperature_unit": "fahrenheit",
              },
          )
          data = response.json()

      # Return a content array - Claude sees this as the tool result
      return {
          "content": [
              {
                  "type": "text",
                  "text": f"Temperature: {data['current']['temperature_2m']}°F",
              }
          ]
      }

  # Wrap the tool in an in-process MCP server
  weather_server = create_sdk_mcp_server(
      name="weather",
      version="1.0.0",
      tools=[get_temperature],
  )

import { tool, createSdkMcpServer } from "@anthropic-ai/claude-agent-sdk";
import { z } from "zod";

// Define a tool: name, description, input schema, handler
const getTemperature = tool(
  "get_temperature",
  "Get the current temperature at a location",
  {
    latitude: z.number().describe("Latitude coordinate"), // .describe() adds a field description Claude sees
    longitude: z.number().describe("Longitude coordinate")
  },
  async (args) => {
    // args is typed from the schema: { latitude: number; longitude: number }
    const response = await fetch(
      `https://api.open-meteo.com/v1/forecast?latitude=${args.latitude}&longitude=${args.longitude}&current=temperature_2m&temperature_unit=fahrenheit`
    );
    const data: any = await response.json();

    // Return a content array - Claude sees this as the tool result
    return {
      content: [{ type: "text", text: `Temperature: ${data.current.temperature_2m}°F` }]
    };
  }
);

// Wrap the tool in an in-process MCP server
const weatherServer = createSdkMcpServer({
  name: "weather",
  version: "1.0.0",
  tools: [getTemperature]
});

  import asyncio
  from claude_agent_sdk import query, ClaudeAgentOptions, ResultMessage

  async def main():
      options = ClaudeAgentOptions(
          mcp_servers={"weather": weather_server},
          allowed_tools=["mcp__weather__get_temperature"],
      )

      async for message in query(
          prompt="What's the temperature in San Francisco?",
          options=options,
      ):
          # ResultMessage is the final message after all tool calls complete
          if isinstance(message, ResultMessage) and message.subtype == "success":
              print(message.result)

  asyncio.run(main())

import { query } from "@anthropic-ai/claude-agent-sdk";

for await (const message of query({
  prompt: "What's the temperature in San Francisco?",
  options: {
    mcpServers: { weather: weatherServer },
    allowedTools: ["mcp__weather__get_temperature"]
  }
})) {
  // "result" is the final message after all tool calls complete
  if (message.type === "result" && message.subtype === "success") {
    console.log(message.result);
  }
}

  # Define a second tool for the same server
  @tool(
      "get_precipitation_chance",
      "Get the hourly precipitation probability for a location. "
      "Optionally pass 'hours' (1-24) to control how many hours to return.",
      {"latitude": float, "longitude": float},
  )
  async def get_precipitation_chance(args: dict[str, Any]) -> dict[str, Any]:
      # 'hours' isn't in the schema - read it with .get() to make it optional
      hours = args.get("hours", 12)
      async with httpx.AsyncClient() as client:
          response = await client.get(
              "https://api.open-meteo.com/v1/forecast",
              params={
                  "latitude": args["latitude"],
                  "longitude": args["longitude"],
                  "hourly": "precipitation_probability",
                  "forecast_days": 1,
              },
          )
          data = response.json()
      chances = data["hourly"]["precipitation_probability"][:hours]

      return {
          "content": [
              {
                  "type": "text",
                  "text": f"Next {hours} hours: {'%, '.join(map(str, chances))}%",
              }
          ]
      }

  # Rebuild the server with both tools in the array
  weather_server = create_sdk_mcp_server(
      name="weather",
      version="1.0.0",
      tools=[get_temperature, get_precipitation_chance],
  )

// Define a second tool for the same server
const getPrecipitationChance = tool(
  "get_precipitation_chance",
  "Get the hourly precipitation probability for a location",
  {
    latitude: z.number(),
    longitude: z.number(),
    hours: z
      .number()
      .int()
      .min(1)
      .max(24)
      .default(12) // .default() makes the parameter optional
      .describe("How many hours of forecast to return")
  },
  async (args) => {
    const response = await fetch(
      `https://api.open-meteo.com/v1/forecast?latitude=${args.latitude}&longitude=${args.longitude}&hourly=precipitation_probability&forecast_days=1`
    );
    const data: any = await response.json();
    const chances = data.hourly.precipitation_probability.slice(0, args.hours);

    return {
      content: [{ type: "text", text: `Next ${args.hours} hours: ${chances.join("%, ")}%` }]
    };
  }
);

// Rebuild the server with both tools in the array
const weatherServer = createSdkMcpServer({
  name: "weather",
  version: "1.0.0",
  tools: [getTemperature, getPrecipitationChance]
});

  from claude_agent_sdk import tool, ToolAnnotations

  @tool(
      "get_temperature",
      "Get the current temperature at a location",
      {"latitude": float, "longitude": float},
      annotations=ToolAnnotations(
          readOnlyHint=True
      ),  # Lets Claude batch this with other read-only calls
  )
  async def get_temperature(args):
      return {"content": [{"type": "text", "text": "..."}]}

tool(
  "get_temperature",
  "Get the current temperature at a location",
  { latitude: z.number(), longitude: z.number() },
  async (args) => ({ content: [{ type: "text", text: `...` }] }),
  { annotations: { readOnlyHint: true } } // Lets Claude batch this with other read-only calls
);

  import json
  import httpx
  from typing import Any

  @tool(
      "fetch_data",
      "Fetch data from an API",
      {"endpoint": str},  # Simple schema
  )
  async def fetch_data(args: dict[str, Any]) -> dict[str, Any]:
      try:
          async with httpx.AsyncClient() as client:
              response = await client.get(args["endpoint"])
              if response.status_code != 200:
                  # Return the failure as a tool result so Claude can react to it.
                  # is_error marks this as a failed call rather than odd-looking data.
                  return {
                      "content": [
                          {
                              "type": "text",
                              "text": f"API error: {response.status_code} {response.reason_phrase}",
                          }
                      ],
                      "is_error": True,
                  }

              data = response.json()
              return {"content": [{"type": "text", "text": json.dumps(data, indent=2)}]}
      except Exception as e:
          # Composes the message Claude reads. An uncaught exception would
          # reach Claude as the raw str(e) with no context.
          return {
              "content": [{"type": "text", "text": f"Failed to fetch data: {str(e)}"}],
              "is_error": True,
          }

tool(
  "fetch_data",
  "Fetch data from an API",
  {
    endpoint: z.string().url().describe("API endpoint URL")
  },
  async (args) => {
    try {
      const response = await fetch(args.endpoint);

      if (!response.ok) {
        // Return the failure as a tool result so Claude can react to it.
        // isError marks this as a failed call rather than odd-looking data.
        return {
          content: [
            {
              type: "text",
              text: `API error: ${response.status} ${response.statusText}`
            }
          ],
          isError: true
        };
      }

      const data = await response.json();
      return {
        content: [
          {
            type: "text",
            text: JSON.stringify(data, null, 2)
          }
        ]
      };
    } catch (error) {
      // Composes the message Claude reads. An uncaught throw would
      // reach Claude as the raw error message with no context.
      return {
        content: [
          {
            type: "text",
            text: `Failed to fetch data: ${error instanceof Error ? error.message : String(error)}`
          }
        ],
        isError: true
      };
    }
  }
);

  import base64
  import httpx

  # Define a tool that fetches an image from a URL and returns it to Claude
  @tool("fetch_image", "Fetch an image from a URL and return it to Claude", {"url": str})
  async def fetch_image(args):
      async with httpx.AsyncClient() as client:  # Fetch the image bytes
          response = await client.get(args["url"])

      return {
          "content": [
              {
                  "type": "image",
                  "data": base64.b64encode(response.content).decode(
                      "ascii"
                  ),  # Base64-encode the raw bytes
                  "mimeType": response.headers.get(
                      "content-type", "image/png"
                  ),  # Read MIME type from the response
              }
          ]
      }

tool(
  "fetch_image",
  "Fetch an image from a URL and return it to Claude",
  {
    url: z.string().url()
  },
  async (args) => {
    const response = await fetch(args.url); // Fetch the image bytes
    const buffer = Buffer.from(await response.arrayBuffer()); // Read into a Buffer for base64 encoding
    const mimeType = response.headers.get("content-type") ?? "image/png";

    return {
      content: [
        {
          type: "image",
          data: buffer.toString("base64"), // Base64-encode the raw bytes
          mimeType
        }
      ]
    };
  }
);

  return {
    content: [
      {
        type: "resource",
        resource: {
          uri: "file:///tmp/report.md", // Label for Claude to reference, not a path the SDK reads
          mimeType: "text/markdown",
          text: "# Report\n..." // The actual content, inline
        }
      }
    ]
  };

return {
    "content": [
        {
            "type": "resource",
            "resource": {
                "uri": "file:///tmp/report.md",  # Label for Claude to reference, not a path the SDK reads
                "mimeType": "text/markdown",
                "text": "# Report\n...",  # The actual content, inline
            },
        }
    ]
}

  from typing import Any
  from claude_agent_sdk import tool, create_sdk_mcp_server

  # z.enum() in TypeScript becomes an "enum" constraint in JSON Schema.
  # The dict schema has no equivalent, so full JSON Schema is required.
  @tool(
      "convert_units",
      "Convert a value from one unit to another",
      {
          "type": "object",
          "properties": {
              "unit_type": {
                  "type": "string",
                  "enum": ["length", "temperature", "weight"],
                  "description": "Category of unit",
              },
              "from_unit": {
                  "type": "string",
                  "description": "Unit to convert from, e.g. kilometers, fahrenheit, pounds",
              },
              "to_unit": {"type": "string", "description": "Unit to convert to"},
              "value": {"type": "number", "description": "Value to convert"},
          },
          "required": ["unit_type", "from_unit", "to_unit", "value"],
      },
  )
  async def convert_units(args: dict[str, Any]) -> dict[str, Any]:
      conversions = {
          "length": {
              "kilometers_to_miles": lambda v: v * 0.621371,
              "miles_to_kilometers": lambda v: v * 1.60934,
              "meters_to_feet": lambda v: v * 3.28084,
              "feet_to_meters": lambda v: v * 0.3048,
          },
          "temperature": {
              "celsius_to_fahrenheit": lambda v: (v * 9) / 5 + 32,
              "fahrenheit_to_celsius": lambda v: (v - 32) * 5 / 9,
              "celsius_to_kelvin": lambda v: v + 273.15,
              "kelvin_to_celsius": lambda v: v - 273.15,
          },
          "weight": {
              "kilograms_to_pounds": lambda v: v * 2.20462,
              "pounds_to_kilograms": lambda v: v * 0.453592,
              "grams_to_ounces": lambda v: v * 0.035274,
              "ounces_to_grams": lambda v: v * 28.3495,
          },
      }

      key = f"{args['from_unit']}_to_{args['to_unit']}"
      fn = conversions.get(args["unit_type"], {}).get(key)

      if not fn:
          return {
              "content": [
                  {
                      "type": "text",
                      "text": f"Unsupported conversion: {args['from_unit']} to {args['to_unit']}",
                  }
              ],
              "is_error": True,
          }

      result = fn(args["value"])
      return {
          "content": [
              {
                  "type": "text",
                  "text": f"{args['value']} {args['from_unit']} = {result:.4f} {args['to_unit']}",
              }
          ]
      }

  converter_server = create_sdk_mcp_server(
      name="converter",
      version="1.0.0",
      tools=[convert_units],
  )

import { tool, createSdkMcpServer } from "@anthropic-ai/claude-agent-sdk";
import { z } from "zod";

const convert = tool(
  "convert_units",
  "Convert a value from one unit to another",
  {
    unit_type: z.enum(["length", "temperature", "weight"]).describe("Category of unit"),
    from_unit: z
      .string()
      .describe("Unit to convert from, e.g. kilometers, fahrenheit, pounds"),
    to_unit: z.string().describe("Unit to convert to"),
    value: z.number().describe("Value to convert")
  },
  async (args) => {
    type Conversions = Record<string, Record<string, (v: number) => number>>;

    const conversions: Conversions = {
      length: {
        kilometers_to_miles: (v) => v * 0.621371,
        miles_to_kilometers: (v) => v * 1.60934,
        meters_to_feet: (v) => v * 3.28084,
        feet_to_meters: (v) => v * 0.3048
      },
      temperature: {
        celsius_to_fahrenheit: (v) => (v * 9) / 5 + 32,
        fahrenheit_to_celsius: (v) => ((v - 32) * 5) / 9,
        celsius_to_kelvin: (v) => v + 273.15,
        kelvin_to_celsius: (v) => v - 273.15
      },
      weight: {
        kilograms_to_pounds: (v) => v * 2.20462,
        pounds_to_kilograms: (v) => v * 0.453592,
        grams_to_ounces: (v) => v * 0.035274,
        ounces_to_grams: (v) => v * 28.3495
      }
    };

    const key = `${args.from_unit}_to_${args.to_unit}`;
    const fn = conversions[args.unit_type]?.[key];

    if (!fn) {
      return {
        content: [
          {
            type: "text",
            text: `Unsupported conversion: ${args.from_unit} to ${args.to_unit}`
          }
        ],
        isError: true
      };
    }

    const result = fn(args.value);
    return {
      content: [
        {
          type: "text",
          text: `${args.value} ${args.from_unit} = ${result.toFixed(4)} ${args.to_unit}`
        }
      ]
    };
  }
);

const converterServer = createSdkMcpServer({
  name: "converter",
  version: "1.0.0",
  tools: [convert]
});

  import asyncio
  from claude_agent_sdk import (
      query,
      ClaudeAgentOptions,
      ResultMessage,
      AssistantMessage,
      ToolUseBlock,
  )

  async def main():
      options = ClaudeAgentOptions(
          mcp_servers={"converter": converter_server},
          allowed_tools=["mcp__converter__convert_units"],
      )

      prompts = [
          "Convert 100 kilometers to miles.",
          "What is 72°F in Celsius?",
          "How many pounds is 5 kilograms?",
      ]

      for prompt in prompts:
          async for message in query(prompt=prompt, options=options):
              if isinstance(message, AssistantMessage):
                  for block in message.content:
                      if isinstance(block, ToolUseBlock):
                          print(f"[tool call] {block.name}({block.input})")
              elif isinstance(message, ResultMessage) and message.subtype == "success":
                  print(f"Q: {prompt}\nA: {message.result}\n")

  asyncio.run(main())

import { query } from "@anthropic-ai/claude-agent-sdk";

const prompts = [
  "Convert 100 kilometers to miles.",
  "What is 72°F in Celsius?",
  "How many pounds is 5 kilograms?"
];

for (const prompt of prompts) {
  for await (const message of query({
    prompt,
    options: {
      mcpServers: { converter: converterServer },
      allowedTools: ["mcp__converter__convert_units"]
    }
  })) {
    if (message.type === "assistant") {
      for (const block of message.message.content) {
        if (block.type === "tool_use") {
          console.log(`[tool call] ${block.name}`, block.input);
        }
      }
    } else if (message.type === "result" && message.subtype === "success") {
      console.log(`Q: ${prompt}\nA: ${message.result}\n`);
    }
  }
}