describe-table
Retrieve the schema details (columns, types, etc.) of a specified table in Firebird SQL databases using the MCP Firebird server. Simplifies table structure analysis.
Instructions
Gets the detailed schema (columns, types, etc.) of a specific table.
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| tableName | Yes | Name of the table to describe |
Implementation Reference
- src/tools/database.ts:213-237 (handler)MCP tool handler for 'describe-table': extracts tableName, calls describeTable(), returns formatted schema or error.handler: async (args: z.infer<typeof DescribeTableArgsSchema>) => { const { tableName } = args; logger.info(`Describing table: ${tableName}`); try { const schema = await describeTable(tableName); logger.info(`Schema obtained for table ${tableName}, ${schema.length} columns found`); return { content: [{ type: "text", text: formatForClaude({ schema }) }] }; } catch (error) { const errorResponse = wrapError(error); logger.error(`Error describiendo tabla ${tableName}: ${errorResponse.error} [${errorResponse.errorType || 'UNKNOWN'}]`); return { content: [{ type: "text", text: formatForClaude(errorResponse) }] }; } }
- src/tools/database.ts:82-84 (schema)Zod input schema for describe-table tool requiring 'tableName' string.export const DescribeTableArgsSchema = z.object({ tableName: z.string().min(1).describe("Name of the table to describe") });
- src/tools/database.ts:209-238 (registration)Local registration of describe-table tool into the database tools Map via setupDatabaseTools().tools.set("describe-table", { name: "describe-table", description: "Gets the detailed schema (columns, types, etc.) of a specific table.", inputSchema: DescribeTableArgsSchema, handler: async (args: z.infer<typeof DescribeTableArgsSchema>) => { const { tableName } = args; logger.info(`Describing table: ${tableName}`); try { const schema = await describeTable(tableName); logger.info(`Schema obtained for table ${tableName}, ${schema.length} columns found`); return { content: [{ type: "text", text: formatForClaude({ schema }) }] }; } catch (error) { const errorResponse = wrapError(error); logger.error(`Error describiendo tabla ${tableName}: ${errorResponse.error} [${errorResponse.errorType || 'UNKNOWN'}]`); return { content: [{ type: "text", text: formatForClaude(errorResponse) }] }; } } });
- src/db/queries.ts:355-446 (helper)Core describeTable helper: queries Firebird system tables to get detailed column schema (name, type, nullable, PK, etc.). Called by tool handler.export const describeTable = async (tableName: string, config = DEFAULT_CONFIG): Promise<ColumnInfo[]> => { // Try to load config from global variable first const globalConfig = getGlobalConfig(); if (globalConfig && globalConfig.database) { logger.info(`Using global configuration for describeTable: ${globalConfig.database}`); config = globalConfig; } try { logger.info(`Obteniendo estructura de la tabla: ${tableName}`); if (!validateSql(tableName)) { throw new FirebirdError( `Nombre de tabla inválido: ${tableName}`, 'VALIDATION_ERROR' ); } // Consulta para obtener información de las columnas const sql = ` SELECT TRIM(rf.RDB$FIELD_NAME) as FIELD_NAME, CASE f.RDB$FIELD_TYPE WHEN 7 THEN 'SMALLINT' WHEN 8 THEN 'INTEGER' WHEN 10 THEN 'FLOAT' WHEN 12 THEN 'DATE' WHEN 13 THEN 'TIME' WHEN 14 THEN 'CHAR' WHEN 16 THEN 'BIGINT' WHEN 27 THEN 'DOUBLE PRECISION' WHEN 35 THEN 'TIMESTAMP' WHEN 37 THEN 'VARCHAR' WHEN 261 THEN 'BLOB' ELSE 'UNKNOWN' END as FIELD_TYPE, f.RDB$FIELD_LENGTH as FIELD_LENGTH, f.RDB$FIELD_SCALE as FIELD_SCALE, CASE rf.RDB$NULL_FLAG WHEN 1 THEN 0 ELSE 1 END as NULLABLE, rf.RDB$DEFAULT_SOURCE as DEFAULT_VALUE, CASE WHEN EXISTS ( SELECT 1 FROM RDB$RELATION_CONSTRAINTS rc JOIN RDB$INDEX_SEGMENTS isg ON rc.RDB$INDEX_NAME = isg.RDB$INDEX_NAME WHERE rc.RDB$RELATION_NAME = rf.RDB$RELATION_NAME AND rc.RDB$CONSTRAINT_TYPE = 'PRIMARY KEY' AND isg.RDB$FIELD_NAME = rf.RDB$FIELD_NAME ) THEN 1 ELSE 0 END as PRIMARY_KEY, CAST(rf.RDB$DESCRIPTION AS VARCHAR(500)) as DESCRIPTION FROM RDB$RELATION_FIELDS rf JOIN RDB$FIELDS f ON rf.RDB$FIELD_SOURCE = f.RDB$FIELD_NAME WHERE rf.RDB$RELATION_NAME = ? ORDER BY rf.RDB$FIELD_POSITION `; const columns = await executeQuery(sql, [tableName], config); if (columns.length === 0) { logger.warn(`No se encontraron columnas para la tabla: ${tableName}`); throw new FirebirdError( `No se encontraron columnas para la tabla: ${tableName}. Es posible que la tabla no exista.`, 'TABLE_NOT_FOUND' ); } logger.info(`Se encontraron ${columns.length} columnas para la tabla: ${tableName}`); return columns.map((col: any) => ({ field_name: col.FIELD_NAME, field_type: col.FIELD_TYPE, field_length: col.FIELD_LENGTH, field_scale: col.FIELD_SCALE !== null ? -1 * col.FIELD_SCALE : undefined, nullable: Boolean(col.NULLABLE), default_value: col.DEFAULT_VALUE, primary_key: Boolean(col.PRIMARY_KEY), description: col.DESCRIPTION || null })); } catch (error: any) { // Propagar el error si ya es un FirebirdError if (error instanceof FirebirdError) { throw error; } const errorMessage = `Error describiendo la tabla ${tableName}: ${error.message || error}`; logger.error(errorMessage); throw new FirebirdError(errorMessage, 'TABLE_DESCRIBE_ERROR', error); } };