Claude にカスタムツールを提供する

from typing import Annotated, 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": Annotated[float, "Latitude coordinate"],
        "longitude": Annotated[float, "Longitude coordinate"],
    },
)
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",
    {
        "type": "object",
        "properties": {
            "latitude": {"type": "number"},
            "longitude": {"type": "number"},
            "hours": {
                "type": "integer",
                "minimum": 1,
                "maximum": 24,
                "description": "How many hours of forecast to return",
            },
        },
        # 'hours' is left out of required, so Claude can omit it
        "required": ["latitude", "longitude"],
    },
)
async def get_precipitation_chance(args: dict[str, Any]) -> dict[str, Any]:
    # 'hours' isn't in required - read it with .get() to fall back to a default
    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)
      .optional() // .optional() lets Claude omit the parameter
      .describe("How many hours of forecast to return")
  },
  async (args) => {
    const hours = args.hours ?? 12; // Apply the default in the handler
    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, hours);

    return {
      content: [{ type: "text", text: `Next ${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": "..."}]}

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

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
from claude_agent_sdk import tool


@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,
        }

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

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
from claude_agent_sdk import tool


# 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
            }
        ]
    }

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

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",  # 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:
        try:
            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")
        except Exception as error:
            # A single-shot query() raises after yielding an error result. Only success
            # results are printed above, so handle the failure here and continue with
            # the next prompt.
            print(f"Call failed: {error}")


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) {
  try {
    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`);
      }
    }
  } catch (error) {
    // A single-shot query() throws after yielding an error result. Only success
    // results are logged above, so handle the failure here and continue with
    // the next prompt.
    console.error(`Call failed: ${error}`);
  }
}