MSSQL MCP Server

Instructions

Implementation Reference

• src/tools/CreateTableTool.ts:28-49 (handler)

  The main execution logic for the create_table tool: validates input, builds SQL CREATE TABLE query from columns, executes it via mssql, returns success/error response.

    async run(params: any) {
      try {
        const { tableName, columns } = params;
        if (!Array.isArray(columns) || columns.length === 0) {
          throw new Error("'columns' must be a non-empty array");
        }
        const columnDefs = columns.map((col: any) => `[${col.name}] ${col.type}`).join(", ");
        const query = `CREATE TABLE [${tableName}] (${columnDefs})`;
        await new sql.Request().query(query);
        return {
          success: true,
          message: `Table '${tableName}' created successfully.`
        };
      } catch (error) {
        console.error("Error creating table:", error);
        return {
          success: false,
          message: `Failed to create table: ${error}`
        };
      }
    }
  }

• src/tools/CreateTableTool.ts:8-26 (schema)

  JSON schema defining input parameters: tableName (string) and columns (array of {name, type} objects).

  inputSchema = {
    type: "object",
    properties: {
      tableName: { type: "string", description: "Name of the table to create" },
      columns: {
        type: "array",
        description: "Array of column definitions (e.g., [{ name: 'id', type: 'INT PRIMARY KEY' }, ...])",
        items: {
          type: "object",
          properties: {
            name: { type: "string", description: "Column name" },
            type: { type: "string", description: "SQL type and constraints (e.g., 'INT PRIMARY KEY', 'NVARCHAR(255) NOT NULL')" }
          },
          required: ["name", "type"]
        }
      }
    },
    required: ["tableName", "columns"],
  } as any;

• src/index.ts:109-113 (registration)

  Registers createTableTool instance in the list of available tools for ListToolsRequest (non-readonly mode).

  server.setRequestHandler(ListToolsRequestSchema, async () => ({
    tools: isReadOnly
      ? [listTableTool, readDataTool, describeTableTool] // todo: add searchDataTool to the list of tools available in readonly mode once implemented
      : [insertDataTool, readDataTool, describeTableTool, updateDataTool, createTableTool, createIndexTool, dropTableTool, listTableTool], // add all new tools here
  }));

• src/index.ts:129-130 (registration)

  Switch case in CallToolRequestHandler that invokes createTableTool.run() when 'create_table' is called.

  case createTableTool.name:
    result = await createTableTool.run(args);

• src/index.ts:86-86 (registration)

  Instantiation of the CreateTableTool class for use in the MCP server.

  const createTableTool = new CreateTableTool();