describe_table
Retrieve the schema and structure of a specific SQLite database table to understand its columns, data types, and constraints.
Instructions
Get the schema/structure of a specific table
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| table_name | Yes | Name of the table to describe |
Implementation Reference
- src/index.ts:246-287 (handler)Executes the describe_table tool: checks database connection, runs PRAGMA table_info(?), formats columns with types, nullability, PK, defaults, and returns formatted schema text.private async describeTable(args: { table_name: string }): Promise<CallToolResult> { if (!this.db) { throw new Error("No database connected. Use connect_database first."); } try { const columns = this.db .prepare("PRAGMA table_info(?)") .all(args.table_name) as { cid: number; name: string; type: string; notnull: number; dflt_value: any; pk: number; }[]; if (columns.length === 0) { throw new Error(`Table '${args.table_name}' not found`); } const schema = columns .map(col => { const nullable = col.notnull === 0 ? "NULL" : "NOT NULL"; const pk = col.pk > 0 ? " PRIMARY KEY" : ""; const defaultVal = col.dflt_value !== null ? ` DEFAULT ${col.dflt_value}` : ""; return ` ${col.name} ${col.type} ${nullable}${pk}${defaultVal}`; }) .join("\n"); return { content: [ { type: "text", text: `Table: ${args.table_name}\n\nSchema:\n${schema}`, } satisfies TextContent, ], }; } catch (error) { throw new Error(`Failed to describe table: ${error instanceof Error ? error.message : String(error)}`); } }
- src/index.ts:86-99 (registration)Registers the describe_table tool in the ListTools response, including name, description, and input schema.{ name: "describe_table", description: "Get the schema/structure of a specific table", inputSchema: { type: "object", properties: { table_name: { type: "string", description: "Name of the table to describe", }, }, required: ["table_name"], }, },
- src/index.ts:89-98 (schema)Defines the input schema for describe_table: object with required 'table_name' string property.inputSchema: { type: "object", properties: { table_name: { type: "string", description: "Name of the table to describe", }, }, required: ["table_name"], },
- src/index.ts:168-170 (handler)Dispatches call_tool requests for describe_table to the describeTable method.case "describe_table": return await this.describeTable(args as { table_name: string });