MCP Resourcesとは？概要と使い方をわかりやすく解説

from mcp.server import Server

from mcp import types

app = Server("example-server")

@app.list_resources()

async def list_resources() -> list[types.Resource]:

    return [

        types.Resource(

            uri="file:///home/user/report.txt",

            name="Annual Report 2024",

            mimeType="text/plain"

        )

    ]

@app.read_resource()

async def read_resource(uri: str) -> str:

    if uri == "file:///home/user/report.txt":

        with open("/home/user/report.txt", "r", encoding="utf-8") as f:

            return f.read()

    raise ValueError("Unsupported resource URI")

git clone https://github.com/modelcontextprotocol/python-sdk.git

cd python-sdk

pip install .

from mcp.server.fastmcp import FastMCP

import os

mcp = FastMCP("local-file-server")

DIRECTORY = ""

# ファイルを読むリソース

@mcp.resource("file:///{filename}")

def read_file(filename: str) -> str:

    filepath = os.path.join(DIRECTORY, filename)

    if not os.path.isfile(filepath):

        raise FileNotFoundError(f"File {filename} not found.")

    with open(filepath, "r", encoding="utf-8") as f:

        return f.read()

# ファイル一覧を出すリソース

@mcp.resource("files://list")

def list_files() -> str:

    files = []

    for filename in os.listdir(DIRECTORY):

        filepath = os.path.join(DIRECTORY, filename)

        if os.path.isfile(filepath):

            files.append(filename)

    return "\n".join(files)

# サンプルテキストを返すリソース

@mcp.resource("test://sample")

def sample_text() -> str:

    return "これはサンプルテキストです。MCPが正常に動作しています。"

if __name__ == "__main__":

    print("Starting MCP server...")

    mcp.run()

import asyncio

from mcp import ClientSession, StdioServerParameters

from mcp.client.stdio import stdio_client

async def test_mcp_resources():

    server_params = StdioServerParameters(

        command="python",

        args=["mcp_Server.py"],

    )

    async with stdio_client(server_params) as (read, write):

        async with ClientSession(read, write) as session:

            await session.initialize()

            # リソース一覧を取得

            print("=== Resource List ===")

            resources_result = await session.list_resources()

            for resource in resources_result.resources:

                print(f"- {resource.name}")

            # テストリソースを読む

            print("\n=== Test Resource ===")

            response = await session.read_resource("test://sample")

            print("Response structure:")

            print(f"Type: {type(response)}")

            print(f"Value: {response}")

            if isinstance(response, tuple) and len(response) == 2:

                meta, contents = response

                print(f"\nMeta: {meta}")

                print(f"Contents type: {type(contents)}")

                if isinstance(contents, list):

                    print("\nContents list:")

                    for item in contents:

                        print(f"Item type: {type(item)}")

                        print(f"Item: {item}")

                        if hasattr(item, 'text'):

                            print(f"Text: {item.text}")

                        elif isinstance(item, dict) and 'text' in item:

                            print(f"Text: {item['text']}")

                        elif isinstance(item, str):

                            print(f"Text: {item}")

            # ファイル一覧を取得

            print("\n=== Files List ===")

            try:

                response = await session.read_resource("files://list")

                print(f"Files response: {response}")

                if isinstance(response, tuple) and len(response) == 2:

                    meta, contents = response

                    if isinstance(contents, list) and contents:

                        content_item = contents[0]

                        if hasattr(content_item, 'text'):

                            files_content = content_item.text

                        elif isinstance(content_item, dict) and 'text' in content_item:

                            files_content = content_item['text']

                        elif isinstance(content_item, str):

                            files_content = content_item

                        else:

                            files_content = str(content_item)

                        print("\nFiles in directory:")

                        for file in files_content.split('\n'):

                            print(f"- {file}")

            except Exception as e:

                print(f"Error processing files list: {type(e).__name__}: {e}")

if __name__ == "__main__":

    asyncio.run(test_mcp_resources())

=== Resource List ===

Processing request of type ListResourcesRequest

- files://list

- test://sample

=== Test Resource ===

Processing request of type ReadResourceRequest

Response structure:

Type: <class 'mcp.types.ReadResourceResult'>

Value: meta=None contents=[TextResourceContents(uri=AnyUrl('test://sample'), mimeType='text/plain', text='これはサンプルテキストです。MCPが正常に動作しています。')]

=== Files List ===

Processing request of type ReadResourceRequest

Files response: meta=None contents=[TextResourceContents(uri=AnyUrl('files://list'), mimeType='text/plain', text='.DS_Store\napp.py\ntestapp.py')]

pip install "mcp[cli]"

uv add "mcp[cli]"

[04/30/25 01:49:16] INFO     Added server 'local-file-server' to Claude config                     claude.py:129

                    INFO     Successfully installed local-file-server in Claude app