fix(mcp-preview): server and tool name fetch to use tanstack (#2058)

* fix(mcp-preview): server and tool name fetch to use tanstack

* remove comments

* fix mcp tool interface

* change incorrect reference

* fix

* remove comments

Author: icecrasher321

apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/workflow-block/workflow-block.tsx

@@ -5,6 +5,7 @@ import { Badge } from '@/components/emcn/components/badge/badge'
 import { Tooltip } from '@/components/emcn/components/tooltip/tooltip'
 import { getEnv, isTruthy } from '@/lib/env'
 import { createLogger } from '@/lib/logs/console/logger'
+import { createMcpToolId } from '@/lib/mcp/utils'
 import { cn } from '@/lib/utils'
 import { useUserPermissionsContext } from '@/app/workspace/[workspaceId]/providers/workspace-permissions-provider'
 import { useBlockCore } from '@/app/workspace/[workspaceId]/w/[workflowId]/hooks'
@@ -13,6 +14,7 @@ import {
   useBlockDimensions,
 } from '@/app/workspace/[workspaceId]/w/[workflowId]/hooks/use-block-dimensions'
 import { SELECTOR_TYPES_HYDRATION_REQUIRED, type SubBlockConfig } from '@/blocks/types'
+import { useMcpServers, useMcpToolsQuery } from '@/hooks/queries/mcp'
 import { useCredentialName } from '@/hooks/queries/oauth-credentials'
 import { useCollaborativeWorkflow } from '@/hooks/use-collaborative-workflow'
 import { useKnowledgeBaseName } from '@/hooks/use-knowledge-base-name'
@@ -313,10 +315,31 @@ const SubBlockRow = ({
       ? (workflowMap[rawValue]?.name ?? null)
       : null
 
-  // Subscribe to variables store to reactively update when variables change
+  // Hydrate MCP server ID to name using TanStack Query
+  const { data: mcpServers = [] } = useMcpServers(workspaceId || '')
+  const mcpServerDisplayName = useMemo(() => {
+    if (subBlock?.type !== 'mcp-server-selector' || typeof rawValue !== 'string') {
+      return null
+    }
+    const server = mcpServers.find((s) => s.id === rawValue)
+    return server?.name ?? null
+  }, [subBlock?.type, rawValue, mcpServers])
+
+  const { data: mcpToolsData = [] } = useMcpToolsQuery(workspaceId || '')
+  const mcpToolDisplayName = useMemo(() => {
+    if (subBlock?.type !== 'mcp-tool-selector' || typeof rawValue !== 'string') {
+      return null
+    }
+
+    const tool = mcpToolsData.find((t) => {
+      const toolId = createMcpToolId(t.serverId, t.name)
+      return toolId === rawValue
+    })
+    return tool?.name ?? null
+  }, [subBlock?.type, rawValue, mcpToolsData])
+
   const allVariables = useVariablesStore((state) => state.variables)
 
-  // Special handling for variables-input to hydrate variable IDs to names from variables store
   const variablesDisplayValue = useMemo(() => {
     if (subBlock?.type !== 'variables-input' || !isVariableAssignmentsArray(rawValue)) {
       return null
@@ -354,6 +377,8 @@ const SubBlockRow = ({
     variablesDisplayValue ||
     knowledgeBaseDisplayName ||
     workflowSelectionName ||
+    mcpServerDisplayName ||
+    mcpToolDisplayName ||
     selectorDisplayName
   const displayValue = maskedValue || hydratedName || (isSelectorType && value ? '-' : value)
 

apps/sim/app/workspace/[workspaceId]/w/components/sidebar/components-new/settings-modal/components/mcp/mcp.tsx

@@ -6,6 +6,7 @@ import { useParams } from 'next/navigation'
 import { Button } from '@/components/emcn'
 import { Alert, AlertDescription, Input, Skeleton } from '@/components/ui'
 import { createLogger } from '@/lib/logs/console/logger'
+import { createMcpToolId } from '@/lib/mcp/utils'
 import { checkEnvVarTrigger } from '@/app/workspace/[workspaceId]/w/[workflowId]/components/panel-new/components/editor/components/sub-block/components/env-var-dropdown'
 import {
   useCreateMcpServer,
@@ -14,7 +15,6 @@ import {
   useMcpToolsQuery,
 } from '@/hooks/queries/mcp'
 import { useMcpServerTest } from '@/hooks/use-mcp-server-test'
-import { useMcpTools } from '@/hooks/use-mcp-tools'
 import { AddServerForm } from './components/add-server-form'
 import type { McpServerFormData } from './types'
 
@@ -34,9 +34,6 @@ export function MCP() {
   const createServerMutation = useCreateMcpServer()
   const deleteServerMutation = useDeleteMcpServer()
 
-  // Keep the old hook for backward compatibility with other features that use it
-  const { refreshTools } = useMcpTools(workspaceId)
-
   const [showAddForm, setShowAddForm] = useState(false)
   const [searchTerm, setSearchTerm] = useState('')
   const [deletingServers, setDeletingServers] = useState<Set<string>>(new Set())
@@ -197,30 +194,20 @@ export function MCP() {
       setActiveInputField(null)
       setActiveHeaderIndex(null)
       clearTestResult()
-
-      refreshTools(true) // Force refresh after adding server
     } catch (error) {
       logger.error('Failed to add MCP server:', error)
     } finally {
       setIsAddingServer(false)
     }
-  }, [
-    formData,
-    testResult,
-    testConnection,
-    createServerMutation,
-    refreshTools,
-    clearTestResult,
-    workspaceId,
-  ])
+  }, [formData, testResult, testConnection, createServerMutation, clearTestResult, workspaceId])
 
   const handleRemoveServer = useCallback(
     async (serverId: string) => {
       setDeletingServers((prev) => new Set(prev).add(serverId))
 
       try {
         await deleteServerMutation.mutateAsync({ workspaceId, serverId })
-        await refreshTools(true)
+        // TanStack Query mutations automatically invalidate and refetch tools
 
         logger.info(`Removed MCP server: ${serverId}`)
       } catch (error) {
@@ -238,7 +225,7 @@ export function MCP() {
         })
       }
     },
-    [deleteServerMutation, refreshTools, workspaceId]
+    [deleteServerMutation, workspaceId]
   )
 
   const toolsByServer = (mcpToolsData || []).reduce(
@@ -392,7 +379,7 @@ export function MCP() {
                       <div className='mt-1 ml-2 flex flex-wrap gap-1'>
                         {tools.map((tool) => (
                           <span
-                            key={tool.id}
+                            key={createMcpToolId(tool.serverId, tool.name)}
                             className='inline-flex h-5 items-center rounded bg-muted/50 px-2 text-muted-foreground text-xs'
                           >
                             {tool.name}

apps/sim/blocks/types.ts

@@ -87,6 +87,8 @@ export const SELECTOR_TYPES_HYDRATION_REQUIRED: SubBlockType[] = [
   'knowledge-base-selector',
   'document-selector',
   'variables-input',
+  'mcp-server-selector',
+  'mcp-tool-selector',
 ] as const
 
 export type ExtractToolOutput<T> = T extends ToolResponse ? T['output'] : never

apps/sim/hooks/queries/mcp.ts

@@ -43,10 +43,11 @@ export interface McpServerConfig {
 }
 
 export interface McpTool {
-  id: string
   serverId: string
+  serverName: string
   name: string
   description?: string
+  inputSchema?: any
 }
 
 /**

apps/sim/hooks/use-mcp-tools.ts

@@ -2,16 +2,16 @@
  * Hook for discovering and managing MCP tools
  *
  * This hook provides a unified interface for accessing MCP tools
- * alongside regular platform tools in the tool-input component
+ * using TanStack Query for optimal caching and performance
  */
 
 import type React from 'react'
-import { useCallback, useEffect, useMemo, useRef, useState } from 'react'
+import { useCallback, useMemo } from 'react'
+import { useQueryClient } from '@tanstack/react-query'
 import { WrenchIcon } from 'lucide-react'
 import { createLogger } from '@/lib/logs/console/logger'
-import type { McpTool } from '@/lib/mcp/types'
 import { createMcpToolId } from '@/lib/mcp/utils'
-import { useMcpServers } from '@/hooks/queries/mcp'
+import { mcpKeys, useMcpToolsQuery } from '@/hooks/queries/mcp'
 
 const logger = createLogger('useMcpTools')
 
@@ -37,81 +37,39 @@ export interface UseMcpToolsResult {
 }
 
 export function useMcpTools(workspaceId: string): UseMcpToolsResult {
-  const [mcpTools, setMcpTools] = useState<McpToolForUI[]>([])
-  const [isLoading, setIsLoading] = useState(false)
-  const [error, setError] = useState<string | null>(null)
-
-  const { data: servers = [] } = useMcpServers(workspaceId)
-
-  // Track the last fingerprint
-  const lastProcessedFingerprintRef = useRef<string>('')
-
-  // Create a stable server fingerprint
-  const serversFingerprint = useMemo(() => {
-    return servers
-      .filter((s) => s.enabled && !s.deletedAt)
-      .map((s) => `${s.id}-${s.enabled}-${s.updatedAt}`)
-      .sort()
-      .join('|')
-  }, [servers])
+  const queryClient = useQueryClient()
+
+  const { data: mcpToolsData = [], isLoading, error: queryError } = useMcpToolsQuery(workspaceId)
+
+  const mcpTools = useMemo<McpToolForUI[]>(() => {
+    return mcpToolsData.map((tool) => ({
+      id: createMcpToolId(tool.serverId, tool.name),
+      name: tool.name,
+      description: tool.description,
+      serverId: tool.serverId,
+      serverName: tool.serverName,
+      type: 'mcp' as const,
+      inputSchema: tool.inputSchema,
+      bgColor: '#6366F1',
+      icon: WrenchIcon,
+    }))
+  }, [mcpToolsData])
 
   const refreshTools = useCallback(
     async (forceRefresh = false) => {
-      // Skip if no workspaceId (e.g., on template preview pages)
       if (!workspaceId) {
-        setMcpTools([])
-        setIsLoading(false)
+        logger.warn('Cannot refresh tools: no workspaceId provided')
         return
       }
 
-      setIsLoading(true)
-      setError(null)
-
-      try {
-        logger.info('Discovering MCP tools', { forceRefresh, workspaceId })
-
-        const response = await fetch(
-          `/api/mcp/tools/discover?workspaceId=${workspaceId}&refresh=${forceRefresh}`
-        )
-
-        if (!response.ok) {
-          throw new Error(`Failed to discover MCP tools: ${response.status} ${response.statusText}`)
-        }
-
-        const data = await response.json()
-
-        if (!data.success) {
-          throw new Error(data.error || 'Failed to discover MCP tools')
-        }
-
-        const tools = data.data.tools || []
-        const transformedTools = tools.map((tool: McpTool) => ({
-          id: createMcpToolId(tool.serverId, tool.name),
-          name: tool.name,
-          description: tool.description,
-          serverId: tool.serverId,
-          serverName: tool.serverName,
-          type: 'mcp' as const,
-          inputSchema: tool.inputSchema,
-          bgColor: '#6366F1',
-          icon: WrenchIcon,
-        }))
-
-        setMcpTools(transformedTools)
-
-        logger.info(
-          `Discovered ${transformedTools.length} MCP tools from ${data.data.byServer ? Object.keys(data.data.byServer).length : 0} servers`
-        )
-      } catch (err) {
-        const errorMessage = err instanceof Error ? err.message : 'Failed to discover MCP tools'
-        logger.error('Error discovering MCP tools:', err)
-        setError(errorMessage)
-        setMcpTools([])
-      } finally {
-        setIsLoading(false)
-      }
+      logger.info('Refreshing MCP tools', { forceRefresh, workspaceId })
+
+      await queryClient.invalidateQueries({
+        queryKey: mcpKeys.tools(workspaceId),
+        refetchType: forceRefresh ? 'active' : 'all',
+      })
     },
-    [workspaceId]
+    [workspaceId, queryClient]
   )
 
   const getToolById = useCallback(
@@ -128,41 +86,10 @@ export function useMcpTools(workspaceId: string): UseMcpToolsResult {
     [mcpTools]
   )
 
-  useEffect(() => {
-    refreshTools()
-  }, [refreshTools])
-
-  // Refresh tools when servers change
-  useEffect(() => {
-    if (!serversFingerprint || serversFingerprint === lastProcessedFingerprintRef.current) return
-
-    logger.info('Active servers changed, refreshing MCP tools', {
-      serverCount: servers.filter((s) => s.enabled && !s.deletedAt).length,
-      fingerprint: serversFingerprint,
-    })
-
-    lastProcessedFingerprintRef.current = serversFingerprint
-    refreshTools()
-  }, [serversFingerprint, refreshTools])
-
-  // Auto-refresh every 5 minutes
-  useEffect(() => {
-    const interval = setInterval(
-      () => {
-        if (!isLoading) {
-          refreshTools()
-        }
-      },
-      5 * 60 * 1000
-    )
-
-    return () => clearInterval(interval)
-  }, [refreshTools])
-
   return {
     mcpTools,
     isLoading,
-    error,
+    error: queryError instanceof Error ? queryError.message : null,
     refreshTools,
     getToolById,
     getToolsByServer,