better error messages, confirmed that permissions works correctly

Author: waleedlatif1

apps/sim/app/api/mcp/servers/route.ts

@@ -1,7 +1,7 @@
 import { and, eq, isNull } from 'drizzle-orm'
 import type { NextRequest } from 'next/server'
 import { createLogger } from '@/lib/logs/console/logger'
-import { withMcpAuth } from '@/lib/mcp/middleware'
+import { getParsedBody, withMcpAuth } from '@/lib/mcp/middleware'
 import { mcpService } from '@/lib/mcp/service'
 import { validateMcpServerUrl } from '@/lib/mcp/url-validator'
 import { createMcpErrorResponse, createMcpSuccessResponse } from '@/lib/mcp/utils'
@@ -46,7 +46,7 @@ export const GET = withMcpAuth('read')(
 export const POST = withMcpAuth('write')(
   async (request: NextRequest, { userId, workspaceId, requestId }) => {
     try {
-      const body = await request.json()
+      const body = getParsedBody(request) || (await request.json())
 
       logger.info(`[${requestId}] Registering new MCP server:`, {
         name: body.name,

apps/sim/app/api/mcp/tools/discover/route.ts

@@ -1,6 +1,6 @@
 import type { NextRequest } from 'next/server'
 import { createLogger } from '@/lib/logs/console/logger'
-import { withMcpAuth } from '@/lib/mcp/middleware'
+import { getParsedBody, withMcpAuth } from '@/lib/mcp/middleware'
 import { mcpService } from '@/lib/mcp/service'
 import type { McpToolDiscoveryResponse } from '@/lib/mcp/types'
 import { categorizeError, createMcpErrorResponse, createMcpSuccessResponse } from '@/lib/mcp/utils'
@@ -61,7 +61,7 @@ export const GET = withMcpAuth('read')(
 export const POST = withMcpAuth('read')(
   async (request: NextRequest, { userId, workspaceId, requestId }) => {
     try {
-      const body = await request.json()
+      const body = getParsedBody(request) || (await request.json())
       const { serverIds } = body
 
       if (!Array.isArray(serverIds)) {

apps/sim/app/api/mcp/tools/execute/route.ts

@@ -104,15 +104,19 @@ export const POST = withMcpAuth('read')(
 
       if (result.isError) {
         logger.warn(`[${requestId}] Tool execution returned error for ${toolName} on ${serverId}`)
-        return createMcpErrorResponse(transformedResult, 'Tool execution failed', 400)
+        return createMcpErrorResponse(
+          transformedResult,
+          transformedResult.error || 'Tool execution failed',
+          400
+        )
       }
       logger.info(`[${requestId}] Successfully executed tool ${toolName} on server ${serverId}`)
       return createMcpSuccessResponse(transformedResult)
     } catch (error) {
       logger.error(`[${requestId}] Error executing MCP tool:`, error)
 
       const { message, status } = categorizeError(error)
-      return createMcpErrorResponse(new Error(message), 'Tool execution failed', status)
+      return createMcpErrorResponse(new Error(message), message, status)
     }
   }
 )

apps/sim/lib/mcp/service.ts

@@ -37,17 +37,27 @@ class McpService {
     if (!envMatches) return value
 
     let resolvedValue = value
+    const missingVars: string[] = []
+
     for (const match of envMatches) {
       const envKey = match.slice(2, -2).trim()
       const envValue = envVars[envKey]
 
       if (envValue === undefined) {
-        logger.warn(`Environment variable "${envKey}" not found in MCP server config`)
+        missingVars.push(envKey)
         continue
       }
 
       resolvedValue = resolvedValue.replace(match, envValue)
     }
+
+    if (missingVars.length > 0) {
+      throw new Error(
+        `Missing required environment variable${missingVars.length > 1 ? 's' : ''}: ${missingVars.join(', ')}. ` +
+          `Please set ${missingVars.length > 1 ? 'these variables' : 'this variable'} in your workspace or personal environment settings.`
+      )
+    }
+
     return resolvedValue
   }