Warp SQL Server MCP

Instructions

Implementation Reference

• lib/tools/handlers/database-tools.js:333-412 (handler)

  Core handler function that generates SQL query execution plans using SQL Server's SHOWPLAN_ALL and SHOWPLAN_TEXT features, with fallback logic, database switching, performance tracking, and result formatting.
  async explainQuery(query, database = null) { try { const pool = await this.getConnection(); const request = pool.request(); // Switch database if specified if (database) { await request.query(`USE [${database}]`); } // Execute the SET SHOWPLAN_ALL ON in a separate batch await request.query('SET SHOWPLAN_ALL ON'); // Execute the query to get the execution plan const result = await request.query(query); // Turn off SHOWPLAN_ALL await request.query('SET SHOWPLAN_ALL OFF'); // Track performance if (this.performanceMonitor) { this.performanceMonitor.recordQuery({ tool: 'explain_query', query, executionTime: 0, // SHOWPLAN doesn't actually execute success: true, database, timestamp: new Date() }); } return this.formatResults(result); } catch { // If SHOWPLAN_ALL doesn't work, try with estimated execution plan try { const pool = await this.getConnection(); const request = pool.request(); // Switch database if specified if (database) { await request.query(`USE [${database}]`); } // Try SET SHOWPLAN_TEXT instead await request.query('SET SHOWPLAN_TEXT ON'); const result = await request.query(query); await request.query('SET SHOWPLAN_TEXT OFF'); // Track performance if (this.performanceMonitor) { this.performanceMonitor.recordQuery({ tool: 'explain_query', query, executionTime: 0, // SHOWPLAN doesn't actually execute success: true, database, timestamp: new Date() }); } return this.formatResults(result); } catch (innerError) { // Track failed query if (this.performanceMonitor) { this.performanceMonitor.recordQuery({ tool: 'explain_query', query, executionTime: 0, success: false, error: innerError.message, database, timestamp: new Date() }); } // Re-throw the error so it can be handled by the caller throw innerError; } } }
• lib/tools/tool-registry.js:145-161 (registration)

  Tool registration definition including name, description, and input schema for the explain_query tool, part of the ANALYSIS_TOOLS array used for MCP tool registry.
  { name: 'explain_query', description: 'Get the execution plan for a SQL query to analyze performance', inputSchema: { type: 'object', properties: { query: { type: 'string', description: 'The SQL query to analyze' }, database: { type: 'string', description: 'Optional: Database name to use for this query' }, include_actual_plan: { type: 'boolean', description: 'Include actual execution statistics (optional, defaults to false)' } }, required: ['query'] } }, {
• lib/tools/tool-registry.js:149-159 (schema)

  Input schema definition for explain_query tool, specifying parameters: query (required string), database (optional string), include_actual_plan (optional boolean).
  type: 'object', properties: { query: { type: 'string', description: 'The SQL query to analyze' }, database: { type: 'string', description: 'Optional: Database name to use for this query' }, include_actual_plan: { type: 'boolean', description: 'Include actual execution statistics (optional, defaults to false)' } }, required: ['query'] }
• index.js:308-311 (handler)

  Dispatch handler in main MCP server that routes explain_query tool calls to the DatabaseToolsHandler instance.
  case 'explain_query': return { content: await this.databaseTools.explainQuery(args.query, args.database) };
• index.js:569-575 (helper)

  Thin wrapper method around databaseTools.explainQuery with error handling for consistency.
  async explainQuery(...args) { try { return { content: await this.databaseTools.explainQuery(...args) }; } catch (error) { throw new McpError(ErrorCode.InternalError, error.message); } }