mcp-development

MCP Development

MCP Server with Tools

import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
import { z } from "zod";

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

server.tool(
  "search_files",
  "Search for files matching a glob pattern in the project directory",
  {
    pattern: z.string().describe("Glob pattern (e.g., '**/*.ts')"),
    directory: z.string().optional().describe("Base directory to search from"),
  },
  async ({ pattern, directory }) => {
    const files = await glob(pattern, { cwd: directory ?? process.cwd() });
    return {
      content: [
        {
          type: "text",
          text: files.length > 0
            ? files.join("\n")
            : `No files found matching ${pattern}`,
        },
      ],
    };
  }
);

server.tool(
  "run_query",
  "Execute a read-only SQL query against the application database",
  {
    query: z.string().describe("SQL SELECT query to execute"),
    limit: z.number().default(100).describe("Maximum rows to return"),
  },
  async ({ query, limit }) => {
    if (!query.trim().toUpperCase().startsWith("SELECT")) {
      return {
        content: [{ type: "text", text: "Only SELECT queries are allowed" }],
        isError: true,
      };
    }
    const rows = await db.query(`${query} LIMIT ${limit}`);
    return {
      content: [{ type: "text", text: JSON.stringify(rows, null, 2) }],
    };
  }
);

Resources

server.resource(
  "schema",
  "db://schema",
  "Current database schema with all tables, columns, and relationships",
  async () => {
    const schema = await db.query(`
      SELECT table_name, column_name, data_type, is_nullable
      FROM information_schema.columns
      WHERE table_schema = 'public'
      ORDER BY table_name, ordinal_position
    `);
    return {
      contents: [
        {
          uri: "db://schema",
          mimeType: "application/json",
          text: JSON.stringify(schema, null, 2),
        },
      ],
    };
  }
);

server.resource(
  "config",
  "config://app",
  "Application configuration (secrets redacted)",
  async () => {
    const config = await loadConfig();
    const safe = redactSecrets(config);
    return {
      contents: [
        {
          uri: "config://app",
          mimeType: "application/json",
          text: JSON.stringify(safe, null, 2),
        },
      ],
    };
  }
);