MySQL MCP Server

Instructions

Implementation Reference

• src/index.ts:258-308 (handler)

  The handler function for the 'create_table' tool. Validates input, checks if it's a CREATE TABLE query, executes it on the MySQL pool, and returns success or error response.

  private async handleCreateTable(request: any, transactionId: string) {
    if (!isValidSqlQueryArgs(request.params.arguments)) {
      throw new McpError(
        ErrorCode.InvalidParams,
        'Invalid SQL query arguments.'
      );
    }
  
    const query = request.params.arguments.query;
    
    if (!isCreateTableQuery(query)) {
      throw new McpError(
        ErrorCode.InvalidParams,
        'Only CREATE TABLE queries are allowed with create_table tool.'
      );
    }
  
    console.error(`[${transactionId}] Executing CREATE TABLE query: ${query}`);
    
    try {
      const [result] = await this.pool.query(query);
      console.error(`[${transactionId}] Table created successfully`);
      
      return {
        content: [
          {
            type: 'text',
            text: JSON.stringify({
              success: true,
              message: 'Table created successfully',
              result
            }, null, 2),
          },
        ],
      };
    } catch (error) {
      console.error(`[${transactionId}] Query error:`, error);
      if (error instanceof Error) {
        return {
          content: [
            {
              type: 'text',
              text: `MySQL error: ${error.message}`,
            },
          ],
          isError: true,
        };
      }
      throw error;
    }
  }

• src/index.ts:111-120 (schema)

  Input schema for the 'create_table' tool, defining the expected 'query' parameter.

  inputSchema: {
    type: 'object',
    properties: {
      query: {
        type: 'string',
        description: 'The SQL CREATE TABLE query to execute.',
      },
    },
    required: ['query'],
  },

• src/index.ts:108-121 (registration)

  Registration of the 'create_table' tool in the ListTools response, including name, description, and schema.

  {
    name: 'create_table',
    description: 'Creates a new table in the MySQL database.',
    inputSchema: {
      type: 'object',
      properties: {
        query: {
          type: 'string',
          description: 'The SQL CREATE TABLE query to execute.',
        },
      },
      required: ['query'],
    },
  },

• src/index.ts:34-35 (helper)

  Helper function used to validate if the provided query starts with 'CREATE TABLE'.

  const isCreateTableQuery = (query: string): boolean => 
    query.trim().toLowerCase().startsWith('create table');

• src/index.ts:189-190 (registration)

  Switch case in CallToolRequestHandler that routes 'create_table' calls to the handler function.

  case 'create_table':
    return this.handleCreateTable(request, transactionId);