Agent Skills vs MCP (Model Context Protocol) 比較

# Agent Skillのディレクトリ構造とSKILL.mdの例
# 出典: anthropics/skillsリポジトリのskill形式(SKILL.md + frontmatter)

pr-checklist/
├── SKILL.md
├── reference.md
└── scripts/
    └── validate.py
---
# SKILL.mdの内容
---
name: pr-checklist
description: Use when opening a pull request in this repo, to apply the team's commit format, required checklist items, and reviewer assignment rules.
---

# Pull Request Checklist

When opening a PR:

1. Commit messages follow Conventional Commits (`feat:`, `fix:`, `refactor:`).
2. Run `scripts/validate.py` before pushing to check the checklist file.
3. Assign at least one reviewer from the CODEOWNERS file.
4. Link the related issue in the PR description.

See `reference.md` for the full checklist template and edge cases.
---
# scripts/validate.py — 必要な時にのみ実行される
import sys

def validate_checklist(pr_body: str) -> list[str]:
    required = ["## Summary", "## Test plan"]
    missing = [item for item in required if item not in pr_body]
    return missing

if __name__ == "__main__":
    body = sys.stdin.read()
    missing = validate_checklist(body)
    if missing:
        print(f"Missing sections: {missing}")
        sys.exit(1)
    print("Checklist OK")

// MCPサーバー — TypeScript SDKによる最小限の"get_order_status"ツール
// 出典: modelcontextprotocol/typescript-sdk README(v2 serverパッケージ)

import { McpServer } from "@modelcontextprotocol/server";
import { StdioServerTransport } from "@modelcontextprotocol/server/stdio";
import * as z from "zod/v4";

const server = new McpServer({
  name: "orders-server",
  version: "1.0.0",
});

server.registerTool(
  "get_order_status",
  {
    title: "Get Order Status",
    description: "Fetch the current status of a customer order from the live database",
    inputSchema: z.object({
      orderId: z.string().describe("The order ID to look up"),
    }),
  },
  async ({ orderId }) => {
    // db: プロジェクト独自のデータベースクライアント(例: Prisma client)
    const order = await db.orders.findUnique({ where: { id: orderId } });
    if (!order) {
      return {
        content: [{ type: "text", text: `Order ${orderId} not found` }],
        isError: true,
      };
    }
    return {
      content: [
        {
          type: "text",
          text: `Order ${orderId}: status=${order.status}, updatedAt=${order.updatedAt.toISOString()}`,
        },
      ],
    };
  }
);

const transport = new StdioServerTransport();
await server.connect(transport);