SQL Server MCP

Instructions

Implementation Reference

• src/tools/query.ts:20-24 (handler)

  The handler function for the "query" MCP tool. It executes the provided SQL query using the database helper, handles empty results, and formats the output using toResult.

  async query({ query }: { query: string }) {
      const results = await database.query(query);
      if (!results.length) return this.toResult("No results found for the query.");
      return this.toResult(JSON.stringify(results));
  }

• src/tools/query.ts:13-13 (schema)

  Input schema definition for the "query" tool using Zod, specifying a string parameter for the SQL query.

  { query: z.string().describe("The SQL query to execute") },

• src/tools/query.ts:10-15 (registration)

  Registration of the "query" tool on the MCP server, including name, description, input schema, and binding to the handler method.

  server.tool(
      "query",
      "Query the database with a SQL statement",
      { query: z.string().describe("The SQL query to execute") },
      tools.query.bind(tools)
  );

• src/utils/database.ts:57-70 (helper)

  Database query helper function called by the tool handler to execute SQL queries against the MSSQL database.

  export async function query(query: string, interpolations: any = null): Promise<mssql.IRecordSet<any>> {
  	let connection = null;
  	try {
  		connection = await connect();
  		const request = connection.request();
  		if (interpolations) {
  			Object.entries(interpolations).forEach(([key, value]) => request.input(key, value));
  		}
  		const { recordset } = await request.query(query);
  		return recordset;
  	} finally {
  		await connection?.close();
  	}
  }

• src/tools/base.ts:9-11 (helper)

  Helper method from BaseTools used by the handler to format tool results as MCP CallToolResult.

  protected toResult(content: string): CallToolResult {
      return { content: [{ type: "text", text: content }] };
  }