USQL MCP Server

Instructions

Implementation Reference

• src/tools/list-tables.ts:42-58 (handler)

  Core handler implementation for the 'list_tables' tool. It resolves the connection string, detects the database type, and generates the appropriate SQL command to list tables using a helper function.
  const _handleListTables = createToolHandler({ name: "list-tables", getQuery: (input) => { // Determine the database type from the connection string const connectionString = resolveConnectionStringOrDefault( (input as Record<string, unknown>).connection_string as string | undefined ); const dbType = detectDatabaseType(connectionString); return getListTablesCommand(dbType); }, errorType: "ListTablesError", getErrorDetails: (input) => ({ ...(input.database && { database: input.database }), }), }); export const handleListTables = withBackgroundSupport("list_tables", _handleListTables);
• src/tools/list-tables.ts:11-40 (schema)

  Input schema definition for the 'list_tables' tool, specifying optional parameters like connection_string, database, output_format, and timeout_ms.
  export const listTablesSchema: Tool = { name: "list_tables", description: "List all tables in a database. Uses default connection if none specified. Automatically detects the database type and uses the appropriate command.", inputSchema: { type: "object", properties: { connection_string: { type: "string", description: '(Optional) Database connection URL or configured connection name. If omitted, uses the default connection from USQL_DEFAULT_CONNECTION (e.g., "oracle" for USQL_ORACLE). Use get_server_info to discover available connections.', }, database: { type: "string", description: "Optional database name to list tables from (if not specified in connection)", }, output_format: { type: "string", enum: ["json", "csv"], description: "Output format for results (default: json)", }, timeout_ms: { type: ["number", "null"], description: "Optional timeout in milliseconds for this call (overrides defaults). Use null for unlimited.", minimum: 1, }, }, required: [], }, };
• src/index.ts:37-46 (registration)

  Registration of the listTablesSchema in the MCP server's list of available tools.
  private tools = [ executeQuerySchema, listDatabasesSchema, listTablesSchema, describeTableSchema, executeScriptSchema, getJobStatusSchema, getServerInfoSchema, cancelJobSchema, ];
• src/index.ts:189-190 (registration)

  Dispatch to the list_tables handler in the server's tool execution switch statement.
  case "list_tables": return await handleListTables(input as Parameters<typeof handleListTables>[0]);
• src/utils/database-mapper.ts:42-79 (helper)

  Helper function that maps database types to specific commands for listing tables, used by the list_tables handler.
  /** * Get the command to list all tables in a database */ export function getListTablesCommand(dbType: string): string { const db = dbType.toLowerCase(); switch (db) { case "postgres": case "cockroach": // PostgreSQL-style return "\\dt"; case "mysql": case "mariadb": // MySQL-style return "SHOW TABLES;"; case "sqlite": // SQLite-style return "SELECT name FROM sqlite_master WHERE type='table' ORDER BY name;"; case "oracle": // Oracle-style return "SELECT table_name FROM user_tables ORDER BY table_name;"; case "sqlserver": // SQL Server-style return "SELECT TABLE_NAME FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_TYPE='BASE TABLE' ORDER BY TABLE_NAME;"; case "mongodb": // MongoDB doesn't have tables, but collections return "db.listCollections();"; default: // Fallback to generic (PostgreSQL-style) return "\\dt"; } }