MCP Troubleshooter

Implementation Reference

• src/index.ts:374-513 (handler)

  Complete tool registration and handler implementation for 'validate-mcp-server-config'. The handler reads claude_desktop_config.json, parses MCP servers section, validates each server's command (checks if in PATH using 'which' or 'where'), ensures 'args' is array and flags relative paths, checks 'env' is object, and generates a markdown validation report listing valid/invalid servers with issues.
  server.tool( "validate-mcp-server-config", { serverName: z.string().optional().describe("Specific server configuration to validate") }, async ({ serverName }) => { try { try { await fs.access(configPath); } catch (error) { return { content: [{ type: "text", text: `Configuration file not found at ${configPath}.` }] }; } const configContent = await fs.readFile(configPath, 'utf-8'); try { const configObject = JSON.parse(configContent); if (!configObject.mcpServers) { return { content: [{ type: "text", text: "Configuration file does not contain an 'mcpServers' section." }] }; } const servers = configObject.mcpServers; const serverNames = Object.keys(servers); if (serverNames.length === 0) { return { content: [{ type: "text", text: "No MCP servers are configured." }] }; } // If a specific server is requested, only validate that one const targetsToValidate = serverName ? (serverNames.includes(serverName) ? [serverName] : []) : serverNames; if (serverName && targetsToValidate.length === 0) { return { content: [{ type: "text", text: `Server '${serverName}' not found in configuration.` }] }; } // Validate each server configuration let validationResults = []; for (const name of targetsToValidate) { const serverConfig = servers[name]; let issues = []; // Check command exists if (!serverConfig.command) { issues.push("Missing 'command' field"); } else { // Try to find the command in PATH try { await execAsync(`which ${serverConfig.command}`); } catch (error) { try { await execAsync(`where ${serverConfig.command}`); } catch (error2) { issues.push(`Command '${serverConfig.command}' not found in PATH`); } } } // Check args if (!serverConfig.args) { issues.push("Missing 'args' field"); } else if (!Array.isArray(serverConfig.args)) { issues.push("'args' field must be an array"); } // Check for relative paths in args that might cause issues if (Array.isArray(serverConfig.args)) { const relativePathArgs = serverConfig.args.filter(arg => typeof arg === 'string' && arg.includes('/') && !arg.startsWith('/') && !arg.includes(':/') ); if (relativePathArgs.length > 0) { issues.push(`Potential relative path issues in args: ${relativePathArgs.join(', ')}`); } } // Check env vars if present if (serverConfig.env && typeof serverConfig.env !== 'object') { issues.push("'env' field must be an object"); } // Add validation result validationResults.push({ server: name, config: serverConfig, valid: issues.length === 0, issues: issues }); } // Format the results let validationReport = "# MCP Server Configuration Validation\n\n"; for (const result of validationResults) { validationReport += `## ${result.server}\n\n`; validationReport += `Status: ${result.valid ? '✅ Valid' : '❌ Invalid'}\n\n`; if (!result.valid) { validationReport += "Issues:\n"; for (const issue of result.issues) { validationReport += `- ${issue}\n`; } validationReport += "\n"; } validationReport += `Configuration:\n\`\`\`json\n${JSON.stringify(result.config, null, 2)}\n\`\`\`\n\n`; } return { content: [{ type: "text", text: validationReport }] }; } catch (error) { return { isError: true, content: [{ type: "text", text: `Error parsing configuration: ${error.message}` }] }; } } catch (error) { return { isError: true, content: [{ type: "text", text: `Error validating configuration: ${error.message}` }] }; } } );
• src/index.ts:376-377 (schema)

  Input schema using Zod: optional serverName string to validate specific server.
  { serverName: z.string().optional().describe("Specific server configuration to validate")
• src/index.ts:374-375 (registration)

  Registration of the tool via server.tool() call.
  server.tool( "validate-mcp-server-config",