mssql_describe_table

Retrieve detailed table structure information including columns, data types, and constraints from Microsoft SQL Server databases for schema analysis and documentation.

Instructions

Get detailed information about a table structure

Input Schema

TableJSON Schema

Name	Required	Description
`server`	Yes	MSSQL Server hostname or IP address
`port`	No	Port number (default: 1433)
`user`	Yes	Username for authentication
`password`	Yes	Password for authentication
`database`	Yes	Database name
`table`	Yes	Table name
`encrypt`	No	Use encrypted connection (default: true)
`trustServerCertificate`	No	Trust server certificate (default: true)

Implementation Reference

src/index.ts:527-572 (handler)

The handler function that executes the mssql_describe_table tool. It parses input arguments using ConnectionSchema, establishes a database connection, queries INFORMATION_SCHEMA.COLUMNS with a LEFT JOIN to identify primary keys, and returns structured JSON with table column details including name, type, nullability, default, lengths, precision, scale, and primary key status.

private async handleDescribeTable(args: any) {
  const config = ConnectionSchema.parse(args);
  const { table } = args;
  const pool = await this.getConnection(config);
  
  const request = pool.request();
  const result = await request.query(`
    USE [${config.database}];
    SELECT 
      c.COLUMN_NAME as column_name,
      c.DATA_TYPE as data_type,
      c.IS_NULLABLE as is_nullable,
      c.COLUMN_DEFAULT as default_value,
      c.CHARACTER_MAXIMUM_LENGTH as max_length,
      c.NUMERIC_PRECISION as precision,
      c.NUMERIC_SCALE as scale,
      CASE WHEN pk.COLUMN_NAME IS NOT NULL THEN 'YES' ELSE 'NO' END as is_primary_key
    FROM INFORMATION_SCHEMA.COLUMNS c
    LEFT JOIN (
      SELECT ku.TABLE_CATALOG, ku.TABLE_SCHEMA, ku.TABLE_NAME, ku.COLUMN_NAME
      FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS AS tc
      INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE AS ku
        ON tc.CONSTRAINT_TYPE = 'PRIMARY KEY'
        AND tc.CONSTRAINT_NAME = ku.CONSTRAINT_NAME
    ) pk ON c.TABLE_CATALOG = pk.TABLE_CATALOG
      AND c.TABLE_SCHEMA = pk.TABLE_SCHEMA
      AND c.TABLE_NAME = pk.TABLE_NAME
      AND c.COLUMN_NAME = pk.COLUMN_NAME
    WHERE c.TABLE_NAME = '${table}'
    ORDER BY c.ORDINAL_POSITION
  `);

  return {
    content: [
      {
        type: 'text',
        text: JSON.stringify({
          server: config.server,
          database: config.database,
          table: table,
          columns: result.recordset,
        }, null, 2),
      },
    ],
  };
}

src/index.ts:308-320 (schema)

Input schema definition for the mssql_describe_table tool, specifying properties like server, port, credentials, database, table, and connection options, with required fields enforced.

inputSchema: {
  type: 'object',
  properties: {
    server: { type: 'string', description: 'MSSQL Server hostname or IP address' },
    port: { type: 'number', description: 'Port number (default: 1433)', default: 1433 },
    user: { type: 'string', description: 'Username for authentication' },
    password: { type: 'string', description: 'Password for authentication' },
    database: { type: 'string', description: 'Database name' },
    table: { type: 'string', description: 'Table name' },
    encrypt: { type: 'boolean', description: 'Use encrypted connection (default: true)', default: true },
    trustServerCertificate: { type: 'boolean', description: 'Trust server certificate (default: true)', default: true },
  },
  required: ['server', 'user', 'password', 'database', 'table'],

src/index.ts:305-322 (registration)

Tool registration in the ListTools response, defining the name, description, and input schema for mssql_describe_table.

{
  name: 'mssql_describe_table',
  description: 'Get detailed information about a table structure',
  inputSchema: {
    type: 'object',
    properties: {
      server: { type: 'string', description: 'MSSQL Server hostname or IP address' },
      port: { type: 'number', description: 'Port number (default: 1433)', default: 1433 },
      user: { type: 'string', description: 'Username for authentication' },
      password: { type: 'string', description: 'Password for authentication' },
      database: { type: 'string', description: 'Database name' },
      table: { type: 'string', description: 'Table name' },
      encrypt: { type: 'boolean', description: 'Use encrypted connection (default: true)', default: true },
      trustServerCertificate: { type: 'boolean', description: 'Trust server certificate (default: true)', default: true },
    },
    required: ['server', 'user', 'password', 'database', 'table'],
  },
},

src/index.ts:441-442 (registration)
Dispatch registration in the CallToolRequest handler switch statement that routes calls to the mssql_describe_table handler function.
```
case 'mssql_describe_table':
  return await this.handleDescribeTable(args);
```

Enhanced MCP MSSQL Server