improvement(mcp): restructure mcp tools caching/fetching info to improve UX (#2416)

* feat(mcp): improve cache practice

* restructure mcps fetching, caching, UX indicators

* fix schema

* styling improvements

* fix tooltips and render issue

* fix loading sequence + add redis

---------

Co-authored-by: waleed <walif6@gmail.com>

apps/sim/app/api/mcp/servers/[id]/refresh/route.ts

@@ -5,6 +5,7 @@ import type { NextRequest } from 'next/server'
 import { createLogger } from '@/lib/logs/console/logger'
 import { withMcpAuth } from '@/lib/mcp/middleware'
 import { mcpService } from '@/lib/mcp/service'
+import type { McpServerStatusConfig } from '@/lib/mcp/types'
 import { createMcpErrorResponse, createMcpSuccessResponse } from '@/lib/mcp/utils'
 
 const logger = createLogger('McpServerRefreshAPI')
@@ -50,6 +51,12 @@ export const POST = withMcpAuth<{ id: string }>('read')(
       let toolCount = 0
       let lastError: string | null = null
 
+      const currentStatusConfig: McpServerStatusConfig =
+        (server.statusConfig as McpServerStatusConfig | null) ?? {
+          consecutiveFailures: 0,
+          lastSuccessfulDiscovery: null,
+        }
+
       try {
         const tools = await mcpService.discoverServerTools(userId, serverId, workspaceId)
         connectionStatus = 'connected'
@@ -63,20 +70,40 @@ export const POST = withMcpAuth<{ id: string }>('read')(
         logger.warn(`[${requestId}] Failed to connect to server ${serverId}:`, error)
       }
 
+      const now = new Date()
+      const newStatusConfig =
+        connectionStatus === 'connected'
+          ? { consecutiveFailures: 0, lastSuccessfulDiscovery: now.toISOString() }
+          : {
+              consecutiveFailures: currentStatusConfig.consecutiveFailures + 1,
+              lastSuccessfulDiscovery: currentStatusConfig.lastSuccessfulDiscovery,
+            }
+
       const [refreshedServer] = await db
         .update(mcpServers)
         .set({
-          lastToolsRefresh: new Date(),
+          lastToolsRefresh: now,
           connectionStatus,
           lastError,
-          lastConnected: connectionStatus === 'connected' ? new Date() : server.lastConnected,
+          lastConnected: connectionStatus === 'connected' ? now : server.lastConnected,
           toolCount,
-          updatedAt: new Date(),
+          statusConfig: newStatusConfig,
+          updatedAt: now,
         })
         .where(eq(mcpServers.id, serverId))
         .returning()
 
-      logger.info(`[${requestId}] Successfully refreshed MCP server: ${serverId}`)
+      if (connectionStatus === 'connected') {
+        logger.info(
+          `[${requestId}] Successfully refreshed MCP server: ${serverId} (${toolCount} tools)`
+        )
+        await mcpService.clearCache(workspaceId)
+      } else {
+        logger.warn(
+          `[${requestId}] Refresh completed for MCP server ${serverId} but connection failed: ${lastError}`
+        )
+      }
+
       return createMcpSuccessResponse({
         status: connectionStatus,
         toolCount,

apps/sim/app/api/mcp/servers/[id]/route.ts

@@ -48,6 +48,19 @@ export const PATCH = withMcpAuth<{ id: string }>('write')(
       // Remove workspaceId from body to prevent it from being updated
       const { workspaceId: _, ...updateData } = body
 
+      // Get the current server to check if URL is changing
+      const [currentServer] = await db
+        .select({ url: mcpServers.url })
+        .from(mcpServers)
+        .where(
+          and(
+            eq(mcpServers.id, serverId),
+            eq(mcpServers.workspaceId, workspaceId),
+            isNull(mcpServers.deletedAt)
+          )
+        )
+        .limit(1)
+
       const [updatedServer] = await db
         .update(mcpServers)
         .set({
@@ -71,8 +84,12 @@ export const PATCH = withMcpAuth<{ id: string }>('write')(
         )
       }
 
-      // Clear MCP service cache after update
-      mcpService.clearCache(workspaceId)
+      // Only clear cache if URL changed (requires re-discovery)
+      const urlChanged = body.url && currentServer?.url !== body.url
+      if (urlChanged) {
+        await mcpService.clearCache(workspaceId)
+        logger.info(`[${requestId}] Cleared cache due to URL change`)
+      }
 
       logger.info(`[${requestId}] Successfully updated MCP server: ${serverId}`)
       return createMcpSuccessResponse({ server: updatedServer })

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

@@ -117,12 +117,14 @@ export const POST = withMcpAuth('write')(
             timeout: body.timeout || 30000,
             retries: body.retries || 3,
             enabled: body.enabled !== false,
+            connectionStatus: 'connected',
+            lastConnected: new Date(),
             updatedAt: new Date(),
             deletedAt: null,
           })
           .where(eq(mcpServers.id, serverId))
 
-        mcpService.clearCache(workspaceId)
+        await mcpService.clearCache(workspaceId)
 
         logger.info(
           `[${requestId}] Successfully updated MCP server: ${body.name} (ID: ${serverId})`
@@ -145,12 +147,14 @@ export const POST = withMcpAuth('write')(
           timeout: body.timeout || 30000,
           retries: body.retries || 3,
           enabled: body.enabled !== false,
+          connectionStatus: 'connected',
+          lastConnected: new Date(),
           createdAt: new Date(),
           updatedAt: new Date(),
         })
         .returning()
 
-      mcpService.clearCache(workspaceId)
+      await mcpService.clearCache(workspaceId)
 
       logger.info(
         `[${requestId}] Successfully registered MCP server: ${body.name} (ID: ${serverId})`
@@ -212,7 +216,7 @@ export const DELETE = withMcpAuth('admin')(
         )
       }
 
-      mcpService.clearCache(workspaceId)
+      await mcpService.clearCache(workspaceId)
 
       logger.info(`[${requestId}] Successfully deleted MCP server: ${serverId}`)
       return createMcpSuccessResponse({ message: `Server ${serverId} deleted successfully` })

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

@@ -0,0 +1,103 @@
+import { db } from '@sim/db'
+import { workflow, workflowBlocks } from '@sim/db/schema'
+import { eq } from 'drizzle-orm'
+import type { NextRequest } from 'next/server'
+import { createLogger } from '@/lib/logs/console/logger'
+import { withMcpAuth } from '@/lib/mcp/middleware'
+import { createMcpErrorResponse, createMcpSuccessResponse } from '@/lib/mcp/utils'
+
+const logger = createLogger('McpStoredToolsAPI')
+
+export const dynamic = 'force-dynamic'
+
+interface StoredMcpTool {
+  workflowId: string
+  workflowName: string
+  serverId: string
+  serverUrl?: string
+  toolName: string
+  schema?: Record<string, unknown>
+}
+
+/**
+ * GET - Get all stored MCP tools from workflows in the workspace
+ *
+ * Scans all workflows in the workspace and extracts MCP tools that have been
+ * added to agent blocks. Returns the stored state of each tool for comparison
+ * against current server state.
+ */
+export const GET = withMcpAuth('read')(
+  async (request: NextRequest, { userId, workspaceId, requestId }) => {
+    try {
+      logger.info(`[${requestId}] Fetching stored MCP tools for workspace ${workspaceId}`)
+
+      // Get all workflows in workspace
+      const workflows = await db
+        .select({
+          id: workflow.id,
+          name: workflow.name,
+        })
+        .from(workflow)
+        .where(eq(workflow.workspaceId, workspaceId))
+
+      const workflowMap = new Map(workflows.map((w) => [w.id, w.name]))
+      const workflowIds = workflows.map((w) => w.id)
+
+      if (workflowIds.length === 0) {
+        return createMcpSuccessResponse({ tools: [] })
+      }
+
+      // Get all agent blocks from these workflows
+      const agentBlocks = await db
+        .select({
+          workflowId: workflowBlocks.workflowId,
+          subBlocks: workflowBlocks.subBlocks,
+        })
+        .from(workflowBlocks)
+        .where(eq(workflowBlocks.type, 'agent'))
+
+      const storedTools: StoredMcpTool[] = []
+
+      for (const block of agentBlocks) {
+        if (!workflowMap.has(block.workflowId)) continue
+
+        const subBlocks = block.subBlocks as Record<string, unknown> | null
+        if (!subBlocks) continue
+
+        const toolsSubBlock = subBlocks.tools as Record<string, unknown> | undefined
+        const toolsValue = toolsSubBlock?.value
+
+        if (!toolsValue || !Array.isArray(toolsValue)) continue
+
+        for (const tool of toolsValue) {
+          if (tool.type !== 'mcp') continue
+
+          const params = tool.params as Record<string, unknown> | undefined
+          if (!params?.serverId || !params?.toolName) continue
+
+          storedTools.push({
+            workflowId: block.workflowId,
+            workflowName: workflowMap.get(block.workflowId) || 'Untitled',
+            serverId: params.serverId as string,
+            serverUrl: params.serverUrl as string | undefined,
+            toolName: params.toolName as string,
+            schema: tool.schema as Record<string, unknown> | undefined,
+          })
+        }
+      }
+
+      logger.info(
+        `[${requestId}] Found ${storedTools.length} stored MCP tools across ${workflows.length} workflows`
+      )
+
+      return createMcpSuccessResponse({ tools: storedTools })
+    } catch (error) {
+      logger.error(`[${requestId}] Error fetching stored MCP tools:`, error)
+      return createMcpErrorResponse(
+        error instanceof Error ? error : new Error('Failed to fetch stored MCP tools'),
+        'Failed to fetch stored MCP tools',
+        500
+      )
+    }
+  }
+)

apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/editor/components/sub-block/components/tool-input/components/mcp-tools-list.tsx

@@ -18,12 +18,18 @@ interface McpTool {
   inputSchema?: any
 }
 
+interface McpServer {
+  id: string
+  url?: string
+}
+
 interface StoredTool {
   type: 'mcp'
   title: string
   toolId: string
   params: {
     serverId: string
+    serverUrl?: string
     toolName: string
     serverName: string
   }
@@ -34,6 +40,7 @@ interface StoredTool {
 
 interface McpToolsListProps {
   mcpTools: McpTool[]
+  mcpServers?: McpServer[]
   searchQuery: string
   customFilter: (name: string, query: string) => number
   onToolSelect: (tool: StoredTool) => void
@@ -45,6 +52,7 @@ interface McpToolsListProps {
  */
 export function McpToolsList({
   mcpTools,
+  mcpServers = [],
   searchQuery,
   customFilter,
   onToolSelect,
@@ -59,44 +67,48 @@ export function McpToolsList({
   return (
     <>
       <PopoverSection>MCP Tools</PopoverSection>
-      {filteredTools.map((mcpTool) => (
-        <ToolCommand.Item
-          key={mcpTool.id}
-          value={mcpTool.name}
-          onSelect={() => {
-            if (disabled) return
+      {filteredTools.map((mcpTool) => {
+        const server = mcpServers.find((s) => s.id === mcpTool.serverId)
+        return (
+          <ToolCommand.Item
+            key={mcpTool.id}
+            value={mcpTool.name}
+            onSelect={() => {
+              if (disabled) return
 
-            const newTool: StoredTool = {
-              type: 'mcp',
-              title: mcpTool.name,
-              toolId: mcpTool.id,
-              params: {
-                serverId: mcpTool.serverId,
-                toolName: mcpTool.name,
-                serverName: mcpTool.serverName,
-              },
-              isExpanded: true,
-              usageControl: 'auto',
-              schema: {
-                ...mcpTool.inputSchema,
-                description: mcpTool.description,
-              },
-            }
+              const newTool: StoredTool = {
+                type: 'mcp',
+                title: mcpTool.name,
+                toolId: mcpTool.id,
+                params: {
+                  serverId: mcpTool.serverId,
+                  serverUrl: server?.url,
+                  toolName: mcpTool.name,
+                  serverName: mcpTool.serverName,
+                },
+                isExpanded: true,
+                usageControl: 'auto',
+                schema: {
+                  ...mcpTool.inputSchema,
+                  description: mcpTool.description,
+                },
+              }
 
-            onToolSelect(newTool)
-          }}
-        >
-          <div
-            className='flex h-[15px] w-[15px] flex-shrink-0 items-center justify-center rounded'
-            style={{ background: mcpTool.bgColor }}
+              onToolSelect(newTool)
+            }}
           >
-            <IconComponent icon={mcpTool.icon} className='h-[11px] w-[11px] text-white' />
-          </div>
-          <span className='truncate' title={`${mcpTool.name} (${mcpTool.serverName})`}>
-            {mcpTool.name}
-          </span>
-        </ToolCommand.Item>
-      ))}
+            <div
+              className='flex h-[15px] w-[15px] flex-shrink-0 items-center justify-center rounded'
+              style={{ background: mcpTool.bgColor }}
+            >
+              <IconComponent icon={mcpTool.icon} className='h-[11px] w-[11px] text-white' />
+            </div>
+            <span className='truncate' title={`${mcpTool.name} (${mcpTool.serverName})`}>
+              {mcpTool.name}
+            </span>
+          </ToolCommand.Item>
+        )
+      })}
     </>
   )
 }

apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/editor/components/sub-block/components/tool-input/tool-input.tsx

@@ -4,6 +4,7 @@ import { useQuery } from '@tanstack/react-query'
 import { Loader2, PlusIcon, WrenchIcon, XIcon } from 'lucide-react'
 import { useParams } from 'next/navigation'
 import {
+  Badge,
   Combobox,
   Popover,
   PopoverContent,
@@ -12,6 +13,7 @@ import {
   PopoverSearch,
   PopoverSection,
   PopoverTrigger,
+  Tooltip,
 } from '@/components/emcn'
 import { McpIcon } from '@/components/icons'
 import { Switch } from '@/components/ui/switch'
@@ -55,9 +57,11 @@ import {
   type CustomTool as CustomToolDefinition,
   useCustomTools,
 } from '@/hooks/queries/custom-tools'
+import { useMcpServers } from '@/hooks/queries/mcp'
 import { useWorkflows } from '@/hooks/queries/workflows'
 import { useMcpTools } from '@/hooks/use-mcp-tools'
 import { getProviderFromModel, supportsToolUsageControl } from '@/providers/utils'
+import { useSettingsModalStore } from '@/stores/settings-modal/store'
 import { useSubBlockStore } from '@/stores/workflows/subblock/store'
 import {
   formatParameterLabel,
@@ -802,6 +806,66 @@ export function ToolInput({
     refreshTools,
   } = useMcpTools(workspaceId)
 
+  const { data: mcpServers = [], isLoading: mcpServersLoading } = useMcpServers(workspaceId)
+  const openSettingsModal = useSettingsModalStore((state) => state.openModal)
+  const mcpDataLoading = mcpLoading || mcpServersLoading
+
+  /**
+   * Returns issue info for an MCP tool using shared validation logic.
+   */
+  const getMcpToolIssue = useCallback(
+    (tool: StoredTool) => {
+      if (tool.type !== 'mcp') return null
+
+      const { getMcpToolIssue: validateTool } = require('@/lib/mcp/tool-validation')
+
+      return validateTool(
+        {
+          serverId: tool.params?.serverId as string,
+          serverUrl: tool.params?.serverUrl as string | undefined,
+          toolName: tool.params?.toolName as string,
+          schema: tool.schema,
+        },
+        mcpServers.map((s) => ({
+          id: s.id,
+          url: s.url,
+          connectionStatus: s.connectionStatus,
+          lastError: s.lastError,
+        })),
+        mcpTools.map((t) => ({
+          serverId: t.serverId,
+          name: t.name,
+          inputSchema: t.inputSchema,
+        }))
+      )
+    },
+    [mcpTools, mcpServers]
+  )
+
+  const isMcpToolUnavailable = useCallback(
+    (tool: StoredTool): boolean => {
+      const { isToolUnavailable } = require('@/lib/mcp/tool-validation')
+      return isToolUnavailable(getMcpToolIssue(tool))
+    },
+    [getMcpToolIssue]
+  )
+
+  const hasMcpToolIssue = useCallback(
+    (tool: StoredTool): boolean => {
+      return getMcpToolIssue(tool) !== null
+    },
+    [getMcpToolIssue]
+  )
+
+  // Filter out MCP tools from unavailable servers for the dropdown
+  const availableMcpTools = useMemo(() => {
+    return mcpTools.filter((mcpTool) => {
+      const server = mcpServers.find((s) => s.id === mcpTool.serverId)
+      // Only include tools from connected servers
+      return server && server.connectionStatus === 'connected'
+    })
+  }, [mcpTools, mcpServers])
+
   // Reset search query when popover opens
   useEffect(() => {
     if (open) {
@@ -1849,9 +1913,10 @@ export function ToolInput({
                       )
                     })()}
 
-                    {/* Display MCP tools */}
+                    {/* Display MCP tools (only from available servers) */}
                     <McpToolsList
-                      mcpTools={mcpTools}
+                      mcpTools={availableMcpTools}
+                      mcpServers={mcpServers}
                       searchQuery={searchQuery || ''}
                       customFilter={customFilter}
                       onToolSelect={handleMcpToolSelect}
@@ -2040,9 +2105,46 @@ export function ToolInput({
                     <span className='truncate font-medium text-[13px] text-[var(--text-primary)]'>
                       {isCustomTool ? customToolTitle : tool.title}
                     </span>
+                    {isMcpTool &&
+                      !mcpDataLoading &&
+                      (() => {
+                        const issue = getMcpToolIssue(tool)
+                        if (!issue) return null
+                        const { getIssueBadgeLabel } = require('@/lib/mcp/tool-validation')
+                        const serverId = tool.params?.serverId
+                        return (
+                          <div
+                            onClick={(e: React.MouseEvent) => {
+                              e.stopPropagation()
+                              e.preventDefault()
+                              openSettingsModal({ section: 'mcp', mcpServerId: serverId })
+                            }}
+                          >
+                            <Tooltip.Root>
+                              <Tooltip.Trigger asChild>
+                                <Badge
+                                  variant='outline'
+                                  className='cursor-pointer transition-colors hover:bg-[var(--warning)]/10'
+                                  style={{
+                                    borderColor: 'var(--warning)',
+                                    color: 'var(--warning)',
+                                  }}
+                                >
+                                  {getIssueBadgeLabel(issue)}
+                                </Badge>
+                              </Tooltip.Trigger>
+                              <Tooltip.Content>
+                                <span className='text-sm'>
+                                  {issue.message} · Click to open settings
+                                </span>
+                              </Tooltip.Content>
+                            </Tooltip.Root>
+                          </div>
+                        )
+                      })()}
                   </div>
                   <div className='flex flex-shrink-0 items-center gap-[8px]'>
-                    {supportsToolControl && (
+                    {supportsToolControl && !(isMcpTool && isMcpToolUnavailable(tool)) && (
                       <Popover
                         open={usageControlPopoverIndex === toolIndex}
                         onOpenChange={(open) =>
@@ -2386,9 +2488,10 @@ export function ToolInput({
                         )
                       })()}
 
-                      {/* Display MCP tools */}
+                      {/* Display MCP tools (only from available servers) */}
                       <McpToolsList
-                        mcpTools={mcpTools}
+                        mcpTools={availableMcpTools}
+                        mcpServers={mcpServers}
                         searchQuery={searchQuery || ''}
                         customFilter={customFilter}
                         onToolSelect={handleMcpToolSelect}

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

@@ -1,8 +1,5 @@
 import { Button } from '@/components/emcn'
 
-/**
- * Formats transport type for display (e.g., "streamable-http" -> "Streamable-HTTP").
- */
 export function formatTransportLabel(transport: string): string {
   return transport
     .split('-')
@@ -14,10 +11,10 @@ export function formatTransportLabel(transport: string): string {
     .join('-')
 }
 
-/**
- * Formats tools count and names for display.
- */
-function formatToolsLabel(tools: any[]): string {
+function formatToolsLabel(tools: any[], connectionStatus?: string): string {
+  if (connectionStatus === 'error') {
+    return 'Unable to connect'
+  }
   const count = tools.length
   const plural = count !== 1 ? 's' : ''
   const names = count > 0 ? `: ${tools.map((t) => t.name).join(', ')}` : ''
@@ -29,35 +26,41 @@ interface ServerListItemProps {
   tools: any[]
   isDeleting: boolean
   isLoadingTools?: boolean
+  isRefreshing?: boolean
   onRemove: () => void
   onViewDetails: () => void
 }
 
-/**
- * Renders a single MCP server list item with details and delete actions.
- */
 export function ServerListItem({
   server,
   tools,
   isDeleting,
   isLoadingTools = false,
+  isRefreshing = false,
   onRemove,
   onViewDetails,
 }: ServerListItemProps) {
   const transportLabel = formatTransportLabel(server.transport || 'http')
-  const toolsLabel = formatToolsLabel(tools)
+  const toolsLabel = formatToolsLabel(tools, server.connectionStatus)
+  const isError = server.connectionStatus === 'error'
 
   return (
     <div className='flex items-center justify-between gap-[12px]'>
       <div className='flex min-w-0 flex-col justify-center gap-[1px]'>
         <div className='flex items-center gap-[6px]'>
-          <span className='max-w-[280px] truncate font-medium text-[14px]'>
+          <span className='max-w-[200px] truncate font-medium text-[14px]'>
             {server.name || 'Unnamed Server'}
           </span>
           <span className='text-[13px] text-[var(--text-secondary)]'>({transportLabel})</span>
         </div>
-        <p className='truncate text-[13px] text-[var(--text-muted)]'>
-          {isLoadingTools && tools.length === 0 ? 'Loading...' : toolsLabel}
+        <p
+          className={`truncate text-[13px] ${isError ? 'text-red-500 dark:text-red-400' : 'text-[var(--text-muted)]'}`}
+        >
+          {isRefreshing
+            ? 'Refreshing...'
+            : isLoadingTools && tools.length === 0
+              ? 'Loading...'
+              : toolsLabel}
         </p>
       </div>
       <div className='flex flex-shrink-0 items-center gap-[4px]'>

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

@@ -1,9 +1,10 @@
 'use client'
 
-import { useCallback, useMemo, useRef, useState } from 'react'
+import { useCallback, useEffect, useMemo, useRef, useState } from 'react'
 import { Plus, Search } from 'lucide-react'
 import { useParams } from 'next/navigation'
 import {
+  Badge,
   Button,
   Input as EmcnInput,
   Modal,
@@ -14,6 +15,7 @@ import {
 } from '@/components/emcn'
 import { Input } from '@/components/ui'
 import { createLogger } from '@/lib/logs/console/logger'
+import { getIssueBadgeLabel, getMcpToolIssue, type McpToolIssue } from '@/lib/mcp/tool-validation'
 import { checkEnvVarTrigger } from '@/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/editor/components/sub-block/components/env-var-dropdown'
 import {
   useCreateMcpServer,
@@ -21,6 +23,7 @@ import {
   useMcpServers,
   useMcpToolsQuery,
   useRefreshMcpServer,
+  useStoredMcpTools,
 } from '@/hooks/queries/mcp'
 import { useMcpServerTest } from '@/hooks/use-mcp-server-test'
 import type { InputFieldType, McpServerFormData, McpServerTestResult } from './components'
@@ -44,6 +47,9 @@ interface McpServer {
   name?: string
   transport?: string
   url?: string
+  connectionStatus?: 'connected' | 'disconnected' | 'error'
+  lastError?: string | null
+  lastConnected?: string
 }
 
 const logger = createLogger('McpSettings')
@@ -69,11 +75,15 @@ function getTestButtonLabel(
   return 'Test Connection'
 }
 
+interface MCPProps {
+  initialServerId?: string | null
+}
+
 /**
  * MCP Settings component for managing Model Context Protocol servers.
  * Handles server CRUD operations, connection testing, and environment variable integration.
  */
-export function MCP() {
+export function MCP({ initialServerId }: MCPProps) {
   const params = useParams()
   const workspaceId = params.workspaceId as string
 
@@ -88,6 +98,7 @@ export function MCP() {
     isLoading: toolsLoading,
     isFetching: toolsFetching,
   } = useMcpToolsQuery(workspaceId)
+  const { data: storedTools = [] } = useStoredMcpTools(workspaceId)
   const createServerMutation = useCreateMcpServer()
   const deleteServerMutation = useDeleteMcpServer()
   const refreshServerMutation = useRefreshMcpServer()
@@ -106,7 +117,9 @@ export function MCP() {
   const [serverToDelete, setServerToDelete] = useState<{ id: string; name: string } | null>(null)
 
   const [selectedServerId, setSelectedServerId] = useState<string | null>(null)
-  const [refreshStatus, setRefreshStatus] = useState<'idle' | 'refreshing' | 'refreshed'>('idle')
+  const [refreshingServers, setRefreshingServers] = useState<
+    Record<string, 'refreshing' | 'refreshed'>
+  >({})
 
   const [showEnvVars, setShowEnvVars] = useState(false)
   const [envSearchTerm, setEnvSearchTerm] = useState('')
@@ -114,10 +127,16 @@ export function MCP() {
   const [activeInputField, setActiveInputField] = useState<InputFieldType | null>(null)
   const [activeHeaderIndex, setActiveHeaderIndex] = useState<number | null>(null)
 
-  // Scroll position state for formatted text overlays
   const [urlScrollLeft, setUrlScrollLeft] = useState(0)
   const [headerScrollLeft, setHeaderScrollLeft] = useState<Record<string, number>>({})
 
+  // Auto-select server when initialServerId is provided
+  useEffect(() => {
+    if (initialServerId && servers.some((s) => s.id === initialServerId)) {
+      setSelectedServerId(initialServerId)
+    }
+  }, [initialServerId, servers])
+
   /**
    * Resets environment variable dropdown state.
    */
@@ -237,6 +256,7 @@ export function MCP() {
 
   /**
    * Adds a new MCP server after validating and testing the connection.
+   * Only creates the server if connection test succeeds.
    */
   const handleAddServer = useCallback(async () => {
     if (!formData.name.trim()) return
@@ -253,12 +273,12 @@ export function MCP() {
         workspaceId,
       }
 
-      if (!testResult) {
-        const result = await testConnection(serverConfig)
-        if (!result.success) return
-      }
+      const connectionResult = await testConnection(serverConfig)
 
-      if (testResult && !testResult.success) return
+      if (!connectionResult.success) {
+        logger.error('Connection test failed, server not added:', connectionResult.error)
+        return
+      }
 
       await createServerMutation.mutateAsync({
         workspaceId,
@@ -279,15 +299,7 @@ export function MCP() {
     } finally {
       setIsAddingServer(false)
     }
-  }, [
-    formData,
-    testResult,
-    testConnection,
-    createServerMutation,
-    workspaceId,
-    headersToRecord,
-    resetForm,
-  ])
+  }, [formData, testConnection, createServerMutation, workspaceId, headersToRecord, resetForm])
 
   /**
    * Opens the delete confirmation dialog for an MCP server.
@@ -297,9 +309,6 @@ export function MCP() {
     setShowDeleteDialog(true)
   }, [])
 
-  /**
-   * Confirms and executes the server deletion.
-   */
   const confirmDeleteServer = useCallback(async () => {
     if (!serverToDelete) return
 
@@ -399,14 +408,24 @@ export function MCP() {
   const handleRefreshServer = useCallback(
     async (serverId: string) => {
       try {
-        setRefreshStatus('refreshing')
+        setRefreshingServers((prev) => ({ ...prev, [serverId]: 'refreshing' }))
         await refreshServerMutation.mutateAsync({ workspaceId, serverId })
         logger.info(`Refreshed MCP server: ${serverId}`)
-        setRefreshStatus('refreshed')
-        setTimeout(() => setRefreshStatus('idle'), 2000)
+        setRefreshingServers((prev) => ({ ...prev, [serverId]: 'refreshed' }))
+        setTimeout(() => {
+          setRefreshingServers((prev) => {
+            const newState = { ...prev }
+            delete newState[serverId]
+            return newState
+          })
+        }, 2000)
       } catch (error) {
         logger.error('Failed to refresh MCP server:', error)
-        setRefreshStatus('idle')
+        setRefreshingServers((prev) => {
+          const newState = { ...prev }
+          delete newState[serverId]
+          return newState
+        })
       }
     },
     [refreshServerMutation, workspaceId]
@@ -432,6 +451,53 @@ export function MCP() {
   const isSubmitDisabled = serversLoading || isAddingServer || !isFormValid
   const testButtonLabel = getTestButtonLabel(testResult, isTestingConnection)
 
+  /**
+   * Gets issues for stored tools that reference a specific server tool.
+   * Returns issues from all workflows that have stored this tool.
+   */
+  const getStoredToolIssues = useCallback(
+    (serverId: string, toolName: string): { issue: McpToolIssue; workflowName: string }[] => {
+      const relevantStoredTools = storedTools.filter(
+        (st) => st.serverId === serverId && st.toolName === toolName
+      )
+
+      const serverStates = servers.map((s) => ({
+        id: s.id,
+        url: s.url,
+        connectionStatus: s.connectionStatus,
+        lastError: s.lastError || undefined,
+      }))
+
+      const discoveredTools = mcpToolsData.map((t) => ({
+        serverId: t.serverId,
+        name: t.name,
+        inputSchema: t.inputSchema,
+      }))
+
+      const issues: { issue: McpToolIssue; workflowName: string }[] = []
+
+      for (const storedTool of relevantStoredTools) {
+        const issue = getMcpToolIssue(
+          {
+            serverId: storedTool.serverId,
+            serverUrl: storedTool.serverUrl,
+            toolName: storedTool.toolName,
+            schema: storedTool.schema,
+          },
+          serverStates,
+          discoveredTools
+        )
+
+        if (issue) {
+          issues.push({ issue, workflowName: storedTool.workflowName })
+        }
+      }
+
+      return issues
+    },
+    [storedTools, servers, mcpToolsData]
+  )
+
   if (selectedServer) {
     const { server, tools } = selectedServer
     const transportLabel = formatTransportLabel(server.transport || 'http')
@@ -463,6 +529,15 @@ export function MCP() {
               </div>
             )}
 
+            {server.connectionStatus === 'error' && (
+              <div className='flex flex-col gap-[8px]'>
+                <span className='font-medium text-[13px] text-[var(--text-primary)]'>Status</span>
+                <p className='text-[14px] text-red-500 dark:text-red-400'>
+                  {server.lastError || 'Unable to connect'}
+                </p>
+              </div>
+            )}
+
             <div className='flex flex-col gap-[8px]'>
               <span className='font-medium text-[13px] text-[var(--text-primary)]'>
                 Tools ({tools.length})
@@ -471,21 +546,37 @@ export function MCP() {
                 <p className='text-[13px] text-[var(--text-muted)]'>No tools available</p>
               ) : (
                 <div className='flex flex-col gap-[8px]'>
-                  {tools.map((tool) => (
-                    <div
-                      key={tool.name}
-                      className='rounded-[6px] border bg-[var(--surface-3)] px-[10px] py-[8px]'
-                    >
-                      <p className='font-medium text-[13px] text-[var(--text-primary)]'>
-                        {tool.name}
-                      </p>
-                      {tool.description && (
-                        <p className='mt-[4px] text-[13px] text-[var(--text-tertiary)]'>
-                          {tool.description}
-                        </p>
-                      )}
-                    </div>
-                  ))}
+                  {tools.map((tool) => {
+                    const issues = getStoredToolIssues(server.id, tool.name)
+                    return (
+                      <div
+                        key={tool.name}
+                        className='rounded-[6px] border bg-[var(--surface-3)] px-[10px] py-[8px]'
+                      >
+                        <div className='flex items-center justify-between'>
+                          <p className='font-medium text-[13px] text-[var(--text-primary)]'>
+                            {tool.name}
+                          </p>
+                          {issues.length > 0 && (
+                            <Badge
+                              variant='outline'
+                              style={{
+                                borderColor: 'var(--warning)',
+                                color: 'var(--warning)',
+                              }}
+                            >
+                              {getIssueBadgeLabel(issues[0].issue)}
+                            </Badge>
+                          )}
+                        </div>
+                        {tool.description && (
+                          <p className='mt-[4px] text-[13px] text-[var(--text-tertiary)]'>
+                            {tool.description}
+                          </p>
+                        )}
+                      </div>
+                    )
+                  })}
                 </div>
               )}
             </div>
@@ -496,11 +587,11 @@ export function MCP() {
           <Button
             onClick={() => handleRefreshServer(server.id)}
             variant='default'
-            disabled={refreshStatus !== 'idle'}
+            disabled={!!refreshingServers[server.id]}
           >
-            {refreshStatus === 'refreshing'
+            {refreshingServers[server.id] === 'refreshing'
               ? 'Refreshing...'
-              : refreshStatus === 'refreshed'
+              : refreshingServers[server.id] === 'refreshed'
                 ? 'Refreshed'
                 : 'Refresh Tools'}
           </Button>
@@ -672,6 +763,7 @@ export function MCP() {
                     tools={tools}
                     isDeleting={deletingServers.has(server.id)}
                     isLoadingTools={isLoadingTools}
+                    isRefreshing={refreshingServers[server.id] === 'refreshing'}
                     onRemove={() => handleRemoveServer(server.id, server.name || 'this server')}
                     onViewDetails={() => handleViewDetails(server.id)}
                   />

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

@@ -46,6 +46,7 @@ import { generalSettingsKeys, useGeneralSettings } from '@/hooks/queries/general
 import { organizationKeys, useOrganizations } from '@/hooks/queries/organization'
 import { ssoKeys, useSSOProviders } from '@/hooks/queries/sso'
 import { subscriptionKeys, useSubscriptionData } from '@/hooks/queries/subscription'
+import { useSettingsModalStore } from '@/stores/settings-modal/store'
 
 const isBillingEnabled = isTruthy(getEnv('NEXT_PUBLIC_BILLING_ENABLED'))
 const isSSOEnabled = isTruthy(getEnv('NEXT_PUBLIC_SSO_ENABLED'))
@@ -134,6 +135,8 @@ const allNavigationItems: NavigationItem[] = [
 
 export function SettingsModal({ open, onOpenChange }: SettingsModalProps) {
   const [activeSection, setActiveSection] = useState<SettingsSection>('general')
+  const { initialSection, mcpServerId, clearInitialState } = useSettingsModalStore()
+  const [pendingMcpServerId, setPendingMcpServerId] = useState<string | null>(null)
   const { data: session } = useSession()
   const queryClient = useQueryClient()
   const { data: organizationsData } = useOrganizations()
@@ -247,6 +250,24 @@ export function SettingsModal({ open, onOpenChange }: SettingsModalProps) {
   // React Query hook automatically loads and syncs settings
   useGeneralSettings()
 
+  // Apply initial section from store when modal opens
+  useEffect(() => {
+    if (open && initialSection) {
+      setActiveSection(initialSection)
+      if (mcpServerId) {
+        setPendingMcpServerId(mcpServerId)
+      }
+      clearInitialState()
+    }
+  }, [open, initialSection, mcpServerId, clearInitialState])
+
+  // Clear pending server ID when section changes away from MCP
+  useEffect(() => {
+    if (activeSection !== 'mcp') {
+      setPendingMcpServerId(null)
+    }
+  }, [activeSection])
+
   useEffect(() => {
     const handleOpenSettings = (event: CustomEvent<{ tab: SettingsSection }>) => {
       setActiveSection(event.detail.tab)
@@ -436,7 +457,7 @@ export function SettingsModal({ open, onOpenChange }: SettingsModalProps) {
             {isBillingEnabled && activeSection === 'team' && <TeamManagement />}
             {activeSection === 'sso' && <SSO />}
             {activeSection === 'copilot' && <Copilot />}
-            {activeSection === 'mcp' && <MCP />}
+            {activeSection === 'mcp' && <MCP initialServerId={pendingMcpServerId} />}
             {activeSection === 'custom-tools' && <CustomTools />}
           </SModalMainBody>
         </SModalMain>

apps/sim/app/workspace/[workspaceId]/w/components/sidebar/sidebar.tsx

@@ -32,6 +32,7 @@ import {
 } from '@/app/workspace/[workspaceId]/w/hooks'
 import { useFolderStore } from '@/stores/folders/store'
 import { useSearchModalStore } from '@/stores/search-modal/store'
+import { useSettingsModalStore } from '@/stores/settings-modal/store'
 import { MIN_SIDEBAR_WIDTH, useSidebarStore } from '@/stores/sidebar/store'
 
 const logger = createLogger('Sidebar')
@@ -88,7 +89,11 @@ export function Sidebar() {
 
   const [isWorkspaceMenuOpen, setIsWorkspaceMenuOpen] = useState(false)
   const [isHelpModalOpen, setIsHelpModalOpen] = useState(false)
-  const [isSettingsModalOpen, setIsSettingsModalOpen] = useState(false)
+  const {
+    isOpen: isSettingsModalOpen,
+    openModal: openSettingsModal,
+    closeModal: closeSettingsModal,
+  } = useSettingsModalStore()
 
   /** Listens for external events to open help modal */
   useEffect(() => {
@@ -219,7 +224,7 @@ export function Sidebar() {
         id: 'settings',
         label: 'Settings',
         icon: Settings,
-        onClick: () => setIsSettingsModalOpen(true),
+        onClick: () => openSettingsModal(),
       },
     ],
     [workspaceId]
@@ -654,7 +659,10 @@ export function Sidebar() {
 
       {/* Footer Navigation Modals */}
       <HelpModal open={isHelpModalOpen} onOpenChange={setIsHelpModalOpen} />
-      <SettingsModal open={isSettingsModalOpen} onOpenChange={setIsSettingsModalOpen} />
+      <SettingsModal
+        open={isSettingsModalOpen}
+        onOpenChange={(open) => (open ? openSettingsModal() : closeSettingsModal())}
+      />
 
       {/* Hidden file input for workspace import */}
       <input

apps/sim/executor/execution/block-executor.ts

@@ -1,3 +1,6 @@
+import { db } from '@sim/db'
+import { mcpServers } from '@sim/db/schema'
+import { and, eq, inArray, isNull } from 'drizzle-orm'
 import { getBaseUrl } from '@/lib/core/utils/urls'
 import { createLogger } from '@/lib/logs/console/logger'
 import {
@@ -72,6 +75,11 @@ export class BlockExecutor {
 
     try {
       resolvedInputs = this.resolver.resolveInputs(ctx, node.id, block.config.params, block)
+
+      if (block.metadata?.id === BlockType.AGENT && resolvedInputs.tools) {
+        resolvedInputs = await this.filterUnavailableMcpToolsForLog(ctx, resolvedInputs)
+      }
+
       if (blockLog) {
         blockLog.input = resolvedInputs
       }
@@ -395,6 +403,60 @@ export class BlockExecutor {
     return undefined
   }
 
+  /**
+   * Filters out unavailable MCP tools from agent inputs for logging.
+   * Only includes tools from servers with 'connected' status.
+   */
+  private async filterUnavailableMcpToolsForLog(
+    ctx: ExecutionContext,
+    inputs: Record<string, any>
+  ): Promise<Record<string, any>> {
+    const tools = inputs.tools
+    if (!Array.isArray(tools) || tools.length === 0) return inputs
+
+    const mcpTools = tools.filter((t: any) => t.type === 'mcp')
+    if (mcpTools.length === 0) return inputs
+
+    const serverIds = [
+      ...new Set(mcpTools.map((t: any) => t.params?.serverId).filter(Boolean)),
+    ] as string[]
+    if (serverIds.length === 0) return inputs
+
+    const availableServerIds = new Set<string>()
+    if (ctx.workspaceId && serverIds.length > 0) {
+      try {
+        const servers = await db
+          .select({ id: mcpServers.id, connectionStatus: mcpServers.connectionStatus })
+          .from(mcpServers)
+          .where(
+            and(
+              eq(mcpServers.workspaceId, ctx.workspaceId),
+              inArray(mcpServers.id, serverIds),
+              isNull(mcpServers.deletedAt)
+            )
+          )
+
+        for (const server of servers) {
+          if (server.connectionStatus === 'connected') {
+            availableServerIds.add(server.id)
+          }
+        }
+      } catch (error) {
+        logger.warn('Failed to check MCP server availability for logging:', error)
+        return inputs
+      }
+    }
+
+    const filteredTools = tools.filter((tool: any) => {
+      if (tool.type !== 'mcp') return true
+      const serverId = tool.params?.serverId
+      if (!serverId) return false
+      return availableServerIds.has(serverId)
+    })
+
+    return { ...inputs, tools: filteredTools }
+  }
+
   private preparePauseResumeSelfReference(
     ctx: ExecutionContext,
     node: DAGNode,

apps/sim/executor/handlers/agent/agent-handler.ts

@@ -1,3 +1,6 @@
+import { db } from '@sim/db'
+import { mcpServers } from '@sim/db/schema'
+import { and, eq, inArray, isNull } from 'drizzle-orm'
 import { createLogger } from '@/lib/logs/console/logger'
 import { createMcpToolId } from '@/lib/mcp/utils'
 import { getAllBlocks } from '@/blocks'
@@ -35,19 +38,23 @@ export class AgentBlockHandler implements BlockHandler {
     block: SerializedBlock,
     inputs: AgentInputs
   ): Promise<BlockOutput | StreamingExecution> {
-    const responseFormat = this.parseResponseFormat(inputs.responseFormat)
-    const model = inputs.model || AGENT.DEFAULT_MODEL
+    // Filter out unavailable MCP tools early so they don't appear in logs/inputs
+    const filteredTools = await this.filterUnavailableMcpTools(ctx, inputs.tools || [])
+    const filteredInputs = { ...inputs, tools: filteredTools }
+
+    const responseFormat = this.parseResponseFormat(filteredInputs.responseFormat)
+    const model = filteredInputs.model || AGENT.DEFAULT_MODEL
     const providerId = getProviderFromModel(model)
-    const formattedTools = await this.formatTools(ctx, inputs.tools || [])
+    const formattedTools = await this.formatTools(ctx, filteredInputs.tools || [])
     const streamingConfig = this.getStreamingConfig(ctx, block)
-    const messages = await this.buildMessages(ctx, inputs, block.id)
+    const messages = await this.buildMessages(ctx, filteredInputs, block.id)
 
     const providerRequest = this.buildProviderRequest({
       ctx,
       providerId,
       model,
       messages,
-      inputs,
+      inputs: filteredInputs,
       formattedTools,
       responseFormat,
       streaming: streamingConfig.shouldUseStreaming ?? false,
@@ -58,10 +65,10 @@ export class AgentBlockHandler implements BlockHandler {
       providerRequest,
       block,
       responseFormat,
-      inputs
+      filteredInputs
     )
 
-    await this.persistResponseToMemory(ctx, inputs, result, block.id)
+    await this.persistResponseToMemory(ctx, filteredInputs, result, block.id)
 
     return result
   }
@@ -115,6 +122,53 @@ export class AgentBlockHandler implements BlockHandler {
     return undefined
   }
 
+  private async filterUnavailableMcpTools(
+    ctx: ExecutionContext,
+    tools: ToolInput[]
+  ): Promise<ToolInput[]> {
+    if (!Array.isArray(tools) || tools.length === 0) return tools
+
+    const mcpTools = tools.filter((t) => t.type === 'mcp')
+    if (mcpTools.length === 0) return tools
+
+    const serverIds = [...new Set(mcpTools.map((t) => t.params?.serverId).filter(Boolean))]
+    if (serverIds.length === 0) return tools
+
+    const availableServerIds = new Set<string>()
+    if (ctx.workspaceId && serverIds.length > 0) {
+      try {
+        const servers = await db
+          .select({ id: mcpServers.id, connectionStatus: mcpServers.connectionStatus })
+          .from(mcpServers)
+          .where(
+            and(
+              eq(mcpServers.workspaceId, ctx.workspaceId),
+              inArray(mcpServers.id, serverIds),
+              isNull(mcpServers.deletedAt)
+            )
+          )
+
+        for (const server of servers) {
+          if (server.connectionStatus === 'connected') {
+            availableServerIds.add(server.id)
+          }
+        }
+      } catch (error) {
+        logger.warn('Failed to check MCP server availability, including all tools:', error)
+        for (const serverId of serverIds) {
+          availableServerIds.add(serverId)
+        }
+      }
+    }
+
+    return tools.filter((tool) => {
+      if (tool.type !== 'mcp') return true
+      const serverId = tool.params?.serverId
+      if (!serverId) return false
+      return availableServerIds.has(serverId)
+    })
+  }
+
   private async formatTools(ctx: ExecutionContext, inputTools: ToolInput[]): Promise<any[]> {
     if (!Array.isArray(inputTools)) return []
 
@@ -304,6 +358,7 @@ export class AgentBlockHandler implements BlockHandler {
 
   /**
    * Process MCP tools using cached schemas from build time.
+   * Note: Unavailable tools are already filtered by filterUnavailableMcpTools.
    */
   private async processMcpToolsBatched(
     ctx: ExecutionContext,
@@ -312,7 +367,6 @@ export class AgentBlockHandler implements BlockHandler {
     if (mcpTools.length === 0) return []
 
     const results: any[] = []
-
     const toolsWithSchema: ToolInput[] = []
     const toolsNeedingDiscovery: ToolInput[] = []
 

apps/sim/hooks/queries/mcp.ts

@@ -1,20 +1,17 @@
 import { keepPreviousData, useMutation, useQuery, useQueryClient } from '@tanstack/react-query'
 import { createLogger } from '@/lib/logs/console/logger'
+import type { McpServerStatusConfig } from '@/lib/mcp/types'
 
 const logger = createLogger('McpQueries')
 
-/**
- * Query key factories for MCP-related queries
- */
+export type { McpServerStatusConfig }
+
 export const mcpKeys = {
   all: ['mcp'] as const,
   servers: (workspaceId: string) => [...mcpKeys.all, 'servers', workspaceId] as const,
   tools: (workspaceId: string) => [...mcpKeys.all, 'tools', workspaceId] as const,
 }
 
-/**
- * MCP Server Types
- */
 export interface McpServer {
   id: string
   workspaceId: string
@@ -25,9 +22,11 @@ export interface McpServer {
   headers?: Record<string, string>
   enabled: boolean
   connectionStatus?: 'connected' | 'disconnected' | 'error'
-  lastError?: string
+  lastError?: string | null
+  statusConfig?: McpServerStatusConfig
   toolCount?: number
   lastToolsRefresh?: string
+  lastConnected?: string
   createdAt: string
   updatedAt: string
   deletedAt?: string
@@ -86,8 +85,13 @@ export function useMcpServers(workspaceId: string) {
 /**
  * Fetch MCP tools for a workspace
  */
-async function fetchMcpTools(workspaceId: string): Promise<McpTool[]> {
-  const response = await fetch(`/api/mcp/tools/discover?workspaceId=${workspaceId}`)
+async function fetchMcpTools(workspaceId: string, forceRefresh = false): Promise<McpTool[]> {
+  const params = new URLSearchParams({ workspaceId })
+  if (forceRefresh) {
+    params.set('refresh', 'true')
+  }
+
+  const response = await fetch(`/api/mcp/tools/discover?${params.toString()}`)
 
   // Treat 404 as "no tools available" - return empty array
   if (response.status === 404) {
@@ -159,14 +163,43 @@ export function useCreateMcpServer() {
       return {
         ...serverData,
         id: serverId,
-        connectionStatus: 'disconnected' as const,
+        connectionStatus: 'connected' as const,
         serverId,
         updated: wasUpdated,
       }
     },
-    onSuccess: (_data, variables) => {
+    onSuccess: async (data, variables) => {
+      const freshTools = await fetchMcpTools(variables.workspaceId, true)
+
+      const previousServers = queryClient.getQueryData<McpServer[]>(
+        mcpKeys.servers(variables.workspaceId)
+      )
+      if (previousServers) {
+        const newServer: McpServer = {
+          id: data.id,
+          workspaceId: variables.workspaceId,
+          name: variables.config.name,
+          transport: variables.config.transport,
+          url: variables.config.url,
+          timeout: variables.config.timeout || 30000,
+          headers: variables.config.headers,
+          enabled: variables.config.enabled,
+          connectionStatus: 'connected',
+          createdAt: new Date().toISOString(),
+          updatedAt: new Date().toISOString(),
+        }
+
+        const serverExists = previousServers.some((s) => s.id === data.id)
+        queryClient.setQueryData<McpServer[]>(
+          mcpKeys.servers(variables.workspaceId),
+          serverExists
+            ? previousServers.map((s) => (s.id === data.id ? { ...s, ...newServer } : s))
+            : [...previousServers, newServer]
+        )
+      }
+
+      queryClient.setQueryData(mcpKeys.tools(variables.workspaceId), freshTools)
       queryClient.invalidateQueries({ queryKey: mcpKeys.servers(variables.workspaceId) })
-      queryClient.invalidateQueries({ queryKey: mcpKeys.tools(variables.workspaceId) })
     },
   })
 }
@@ -213,7 +246,7 @@ export function useDeleteMcpServer() {
 interface UpdateMcpServerParams {
   workspaceId: string
   serverId: string
-  updates: Partial<McpServerConfig>
+  updates: Partial<McpServerConfig & { enabled?: boolean }>
 }
 
 export function useUpdateMcpServer() {
@@ -221,8 +254,20 @@ export function useUpdateMcpServer() {
 
   return useMutation({
     mutationFn: async ({ workspaceId, serverId, updates }: UpdateMcpServerParams) => {
+      const response = await fetch(`/api/mcp/servers/${serverId}?workspaceId=${workspaceId}`, {
+        method: 'PATCH',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify(updates),
+      })
+
+      const data = await response.json()
+
+      if (!response.ok) {
+        throw new Error(data.error || 'Failed to update MCP server')
+      }
+
       logger.info(`Updated MCP server: ${serverId} in workspace: ${workspaceId}`)
-      return { serverId, updates }
+      return data.data?.server
     },
     onMutate: async ({ workspaceId, serverId, updates }) => {
       await queryClient.cancelQueries({ queryKey: mcpKeys.servers(workspaceId) })
@@ -249,6 +294,7 @@ export function useUpdateMcpServer() {
     },
     onSettled: (_data, _error, variables) => {
       queryClient.invalidateQueries({ queryKey: mcpKeys.servers(variables.workspaceId) })
+      queryClient.invalidateQueries({ queryKey: mcpKeys.tools(variables.workspaceId) })
     },
   })
 }
@@ -292,9 +338,10 @@ export function useRefreshMcpServer() {
       logger.info(`Refreshed MCP server: ${serverId}`)
       return data.data
     },
-    onSuccess: (_data, variables) => {
+    onSuccess: async (_data, variables) => {
       queryClient.invalidateQueries({ queryKey: mcpKeys.servers(variables.workspaceId) })
-      queryClient.invalidateQueries({ queryKey: mcpKeys.tools(variables.workspaceId) })
+      const freshTools = await fetchMcpTools(variables.workspaceId, true)
+      queryClient.setQueryData(mcpKeys.tools(variables.workspaceId), freshTools)
     },
   })
 }
@@ -349,3 +396,42 @@ export function useTestMcpServer() {
     },
   })
 }
+
+/**
+ * Stored MCP tool from workflow state
+ */
+export interface StoredMcpTool {
+  workflowId: string
+  workflowName: string
+  serverId: string
+  serverUrl?: string
+  toolName: string
+  schema?: Record<string, unknown>
+}
+
+/**
+ * Fetch stored MCP tools from all workflows in the workspace
+ */
+async function fetchStoredMcpTools(workspaceId: string): Promise<StoredMcpTool[]> {
+  const response = await fetch(`/api/mcp/tools/stored?workspaceId=${workspaceId}`)
+
+  if (!response.ok) {
+    const data = await response.json().catch(() => ({}))
+    throw new Error(data.error || 'Failed to fetch stored MCP tools')
+  }
+
+  const data = await response.json()
+  return data.data?.tools || []
+}
+
+/**
+ * Hook to fetch stored MCP tools from all workflows
+ */
+export function useStoredMcpTools(workspaceId: string) {
+  return useQuery({
+    queryKey: [...mcpKeys.all, workspaceId, 'stored'],
+    queryFn: () => fetchStoredMcpTools(workspaceId),
+    enabled: !!workspaceId,
+    staleTime: 60 * 1000, // 1 minute - workflows don't change frequently
+  })
+}

apps/sim/hooks/use-mcp-server-test.ts

@@ -34,14 +34,19 @@ export function useMcpServerTest() {
   const [isTestingConnection, setIsTestingConnection] = useState(false)
 
   const testConnection = useCallback(
-    async (config: McpServerTestConfig): Promise<McpServerTestResult> => {
+    async (
+      config: McpServerTestConfig,
+      options?: { silent?: boolean }
+    ): Promise<McpServerTestResult> => {
+      const { silent = false } = options || {}
+
       if (!config.name || !config.transport || !config.workspaceId) {
         const result: McpServerTestResult = {
           success: false,
           message: 'Missing required configuration',
           error: 'Please provide server name, transport method, and workspace ID',
         }
-        setTestResult(result)
+        if (!silent) setTestResult(result)
         return result
       }
 
@@ -51,12 +56,14 @@ export function useMcpServerTest() {
           message: 'Missing server URL',
           error: 'Please provide a server URL for HTTP/SSE transport',
         }
-        setTestResult(result)
+        if (!silent) setTestResult(result)
         return result
       }
 
-      setIsTestingConnection(true)
-      setTestResult(null)
+      if (!silent) {
+        setIsTestingConnection(true)
+        setTestResult(null)
+      }
 
       try {
         const cleanConfig = {
@@ -88,14 +95,14 @@ export function useMcpServerTest() {
               error: result.data.error,
               warnings: result.data.warnings,
             }
-            setTestResult(testResult)
+            if (!silent) setTestResult(testResult)
             logger.error('MCP server test failed:', result.data.error)
             return testResult
           }
           throw new Error(result.error || 'Connection test failed')
         }
 
-        setTestResult(result.data || result)
+        if (!silent) setTestResult(result.data || result)
         logger.info(`MCP server test ${result.data?.success ? 'passed' : 'failed'}:`, config.name)
         return result.data || result
       } catch (error) {
@@ -105,11 +112,11 @@ export function useMcpServerTest() {
           message: 'Connection failed',
           error: errorMessage,
         }
-        setTestResult(result)
+        if (!silent) setTestResult(result)
         logger.error('MCP server test failed:', errorMessage)
         return result
       } finally {
-        setIsTestingConnection(false)
+        if (!silent) setIsTestingConnection(false)
       }
     },
     []

apps/sim/lib/mcp/client.ts

@@ -108,7 +108,7 @@ export class McpClient {
       this.connectionStatus.lastError = errorMessage
       this.isConnected = false
       logger.error(`Failed to connect to MCP server ${this.config.name}:`, error)
-      throw new McpConnectionError(errorMessage, this.config.id)
+      throw new McpConnectionError(errorMessage, this.config.name)
     }
   }
 
@@ -141,7 +141,7 @@ export class McpClient {
    */
   async listTools(): Promise<McpTool[]> {
     if (!this.isConnected) {
-      throw new McpConnectionError('Not connected to server', this.config.id)
+      throw new McpConnectionError('Not connected to server', this.config.name)
     }
 
     try {
@@ -170,7 +170,7 @@ export class McpClient {
    */
   async callTool(toolCall: McpToolCall): Promise<McpToolResult> {
     if (!this.isConnected) {
-      throw new McpConnectionError('Not connected to server', this.config.id)
+      throw new McpConnectionError('Not connected to server', this.config.name)
     }
 
     const consentRequest: McpConsentRequest = {
@@ -217,7 +217,7 @@ export class McpClient {
    */
   async ping(): Promise<{ _meta?: Record<string, any> }> {
     if (!this.isConnected) {
-      throw new McpConnectionError('Not connected to server', this.config.id)
+      throw new McpConnectionError('Not connected to server', this.config.name)
     }
 
     try {

apps/sim/lib/mcp/service.ts

@@ -10,8 +10,14 @@ import { generateRequestId } from '@/lib/core/utils/request'
 import { getEffectiveDecryptedEnv } from '@/lib/environment/utils'
 import { createLogger } from '@/lib/logs/console/logger'
 import { McpClient } from '@/lib/mcp/client'
+import {
+  createMcpCacheAdapter,
+  getMcpCacheType,
+  type McpCacheStorageAdapter,
+} from '@/lib/mcp/storage'
 import type {
   McpServerConfig,
+  McpServerStatusConfig,
   McpServerSummary,
   McpTool,
   McpToolCall,
@@ -22,154 +28,21 @@ import { MCP_CONSTANTS } from '@/lib/mcp/utils'
 
 const logger = createLogger('McpService')
 
-interface ToolCache {
-  tools: McpTool[]
-  expiry: Date
-  lastAccessed: Date
-}
-
-interface CacheStats {
-  totalEntries: number
-  activeEntries: number
-  expiredEntries: number
-  maxCacheSize: number
-  cacheHitRate: number
-  memoryUsage: {
-    approximateBytes: number
-    entriesEvicted: number
-  }
-}
-
 class McpService {
-  private toolCache = new Map<string, ToolCache>()
-  private readonly cacheTimeout = MCP_CONSTANTS.CACHE_TIMEOUT // 30 seconds
-  private readonly maxCacheSize = MCP_CONSTANTS.MAX_CACHE_SIZE // 1000
-  private cleanupInterval: NodeJS.Timeout | null = null
-  private cacheHits = 0
-  private cacheMisses = 0
-  private entriesEvicted = 0
+  private cacheAdapter: McpCacheStorageAdapter
+  private readonly cacheTimeout = MCP_CONSTANTS.CACHE_TIMEOUT // 5 minutes
 
   constructor() {
-    this.startPeriodicCleanup()
-  }
-
-  /**
-   * Start periodic cleanup of expired cache entries
-   */
-  private startPeriodicCleanup(): void {
-    this.cleanupInterval = setInterval(
-      () => {
-        this.cleanupExpiredEntries()
-      },
-      5 * 60 * 1000
-    )
-  }
-
-  /**
-   * Stop periodic cleanup
-   */
-  private stopPeriodicCleanup(): void {
-    if (this.cleanupInterval) {
-      clearInterval(this.cleanupInterval)
-      this.cleanupInterval = null
-    }
-  }
-
-  /**
-   * Cleanup expired cache entries
-   */
-  private cleanupExpiredEntries(): void {
-    const now = new Date()
-    const expiredKeys: string[] = []
-
-    this.toolCache.forEach((cache, key) => {
-      if (cache.expiry <= now) {
-        expiredKeys.push(key)
-      }
-    })
-
-    expiredKeys.forEach((key) => this.toolCache.delete(key))
-
-    if (expiredKeys.length > 0) {
-      logger.debug(`Cleaned up ${expiredKeys.length} expired cache entries`)
-    }
-  }
-
-  /**
-   * Evict least recently used entries when cache exceeds max size
-   */
-  private evictLRUEntries(): void {
-    if (this.toolCache.size <= this.maxCacheSize) {
-      return
-    }
-
-    const entries: { key: string; cache: ToolCache }[] = []
-    this.toolCache.forEach((cache, key) => {
-      entries.push({ key, cache })
-    })
-    entries.sort((a, b) => a.cache.lastAccessed.getTime() - b.cache.lastAccessed.getTime())
-
-    const entriesToRemove = this.toolCache.size - this.maxCacheSize + 1
-    for (let i = 0; i < entriesToRemove && i < entries.length; i++) {
-      this.toolCache.delete(entries[i].key)
-      this.entriesEvicted++
-    }
-
-    logger.debug(`Evicted ${entriesToRemove} LRU cache entries to maintain size limit`)
-  }
-
-  /**
-   * Get cache entry and update last accessed time
-   */
-  private getCacheEntry(key: string): ToolCache | undefined {
-    const entry = this.toolCache.get(key)
-    if (entry) {
-      entry.lastAccessed = new Date()
-      this.cacheHits++
-      return entry
-    }
-    this.cacheMisses++
-    return undefined
-  }
-
-  /**
-   * Set cache entry with LRU eviction
-   */
-  private setCacheEntry(key: string, tools: McpTool[]): void {
-    const now = new Date()
-    const cache: ToolCache = {
-      tools,
-      expiry: new Date(now.getTime() + this.cacheTimeout),
-      lastAccessed: now,
-    }
-
-    this.toolCache.set(key, cache)
-
-    this.evictLRUEntries()
-  }
-
-  /**
-   * Calculate approximate memory usage of cache
-   */
-  private calculateMemoryUsage(): number {
-    let totalBytes = 0
-
-    this.toolCache.forEach((cache, key) => {
-      totalBytes += key.length * 2 // UTF-16 encoding
-      totalBytes += JSON.stringify(cache.tools).length * 2
-      totalBytes += 64
-    })
-
-    return totalBytes
+    this.cacheAdapter = createMcpCacheAdapter()
+    logger.info(`MCP Service initialized with ${getMcpCacheType()} cache`)
   }
 
   /**
    * Dispose of the service and cleanup resources
    */
   dispose(): void {
-    this.stopPeriodicCleanup()
-    this.toolCache.clear()
-    logger.info('MCP Service disposed and cleanup stopped')
+    this.cacheAdapter.dispose()
+    logger.info('MCP Service disposed')
   }
 
   /**
@@ -385,6 +258,81 @@ class McpService {
     )
   }
 
+  /**
+   * Update server connection status after discovery attempt
+   */
+  private async updateServerStatus(
+    serverId: string,
+    workspaceId: string,
+    success: boolean,
+    error?: string,
+    toolCount?: number
+  ): Promise<void> {
+    try {
+      const [currentServer] = await db
+        .select({ statusConfig: mcpServers.statusConfig })
+        .from(mcpServers)
+        .where(
+          and(
+            eq(mcpServers.id, serverId),
+            eq(mcpServers.workspaceId, workspaceId),
+            isNull(mcpServers.deletedAt)
+          )
+        )
+        .limit(1)
+
+      const currentConfig: McpServerStatusConfig =
+        (currentServer?.statusConfig as McpServerStatusConfig | null) ?? {
+          consecutiveFailures: 0,
+          lastSuccessfulDiscovery: null,
+        }
+
+      const now = new Date()
+
+      if (success) {
+        await db
+          .update(mcpServers)
+          .set({
+            connectionStatus: 'connected',
+            lastConnected: now,
+            lastError: null,
+            toolCount: toolCount ?? 0,
+            lastToolsRefresh: now,
+            statusConfig: {
+              consecutiveFailures: 0,
+              lastSuccessfulDiscovery: now.toISOString(),
+            },
+            updatedAt: now,
+          })
+          .where(eq(mcpServers.id, serverId))
+      } else {
+        const newFailures = currentConfig.consecutiveFailures + 1
+        const isErrorState = newFailures >= MCP_CONSTANTS.MAX_CONSECUTIVE_FAILURES
+
+        await db
+          .update(mcpServers)
+          .set({
+            connectionStatus: isErrorState ? 'error' : 'disconnected',
+            lastError: error || 'Unknown error',
+            statusConfig: {
+              consecutiveFailures: newFailures,
+              lastSuccessfulDiscovery: currentConfig.lastSuccessfulDiscovery,
+            },
+            updatedAt: now,
+          })
+          .where(eq(mcpServers.id, serverId))
+
+        if (isErrorState) {
+          logger.warn(
+            `Server ${serverId} marked as error after ${newFailures} consecutive failures`
+          )
+        }
+      }
+    } catch (err) {
+      logger.error(`Failed to update server status for ${serverId}:`, err)
+    }
+  }
+
   /**
    * Discover tools from all workspace servers
    */
@@ -399,10 +347,14 @@ class McpService {
 
     try {
       if (!forceRefresh) {
-        const cached = this.getCacheEntry(cacheKey)
-        if (cached && cached.expiry > new Date()) {
-          logger.debug(`[${requestId}] Using cached tools for user ${userId}`)
-          return cached.tools
+        try {
+          const cached = await this.cacheAdapter.get(cacheKey)
+          if (cached) {
+            logger.debug(`[${requestId}] Using cached tools for user ${userId}`)
+            return cached.tools
+          }
+        } catch (error) {
+          logger.warn(`[${requestId}] Cache read failed, proceeding with discovery:`, error)
         }
       }
 
@@ -425,7 +377,7 @@ class McpService {
             logger.debug(
               `[${requestId}] Discovered ${tools.length} tools from server ${config.name}`
             )
-            return tools
+            return { serverId: config.id, tools }
           } finally {
             await client.disconnect()
           }
@@ -433,20 +385,44 @@ class McpService {
       )
 
       let failedCount = 0
+      const statusUpdates: Promise<void>[] = []
+
       results.forEach((result, index) => {
+        const server = servers[index]
         if (result.status === 'fulfilled') {
-          allTools.push(...result.value)
+          allTools.push(...result.value.tools)
+          statusUpdates.push(
+            this.updateServerStatus(
+              server.id!,
+              workspaceId,
+              true,
+              undefined,
+              result.value.tools.length
+            )
+          )
         } else {
           failedCount++
+          const errorMessage =
+            result.reason instanceof Error ? result.reason.message : 'Unknown error'
           logger.warn(
-            `[${requestId}] Failed to discover tools from server ${servers[index].name}:`,
+            `[${requestId}] Failed to discover tools from server ${server.name}:`,
             result.reason
           )
+          statusUpdates.push(this.updateServerStatus(server.id!, workspaceId, false, errorMessage))
         }
       })
 
+      // Update server statuses in parallel (don't block on this)
+      Promise.allSettled(statusUpdates).catch((err) => {
+        logger.error(`[${requestId}] Error updating server statuses:`, err)
+      })
+
       if (failedCount === 0) {
-        this.setCacheEntry(cacheKey, allTools)
+        try {
+          await this.cacheAdapter.set(cacheKey, allTools, this.cacheTimeout)
+        } catch (error) {
+          logger.warn(`[${requestId}] Cache write failed:`, error)
+        }
       } else {
         logger.warn(
           `[${requestId}] Skipping cache due to ${failedCount} failed server(s) - will retry on next request`
@@ -565,44 +541,18 @@ class McpService {
   /**
    * Clear tool cache for a workspace or all workspaces
    */
-  clearCache(workspaceId?: string): void {
-    if (workspaceId) {
-      const workspaceCacheKey = `workspace:${workspaceId}`
-      this.toolCache.delete(workspaceCacheKey)
-      logger.debug(`Cleared MCP tool cache for workspace ${workspaceId}`)
-    } else {
-      this.toolCache.clear()
-      this.cacheHits = 0
-      this.cacheMisses = 0
-      this.entriesEvicted = 0
-      logger.debug('Cleared all MCP tool cache and reset statistics')
-    }
-  }
-
-  /**
-   * Get comprehensive cache statistics
-   */
-  getCacheStats(): CacheStats {
-    const entries: { key: string; cache: ToolCache }[] = []
-    this.toolCache.forEach((cache, key) => {
-      entries.push({ key, cache })
-    })
-
-    const now = new Date()
-    const activeEntries = entries.filter(({ cache }) => cache.expiry > now)
-    const totalRequests = this.cacheHits + this.cacheMisses
-    const hitRate = totalRequests > 0 ? this.cacheHits / totalRequests : 0
-
-    return {
-      totalEntries: entries.length,
-      activeEntries: activeEntries.length,
-      expiredEntries: entries.length - activeEntries.length,
-      maxCacheSize: this.maxCacheSize,
-      cacheHitRate: Math.round(hitRate * 100) / 100,
-      memoryUsage: {
-        approximateBytes: this.calculateMemoryUsage(),
-        entriesEvicted: this.entriesEvicted,
-      },
+  async clearCache(workspaceId?: string): Promise<void> {
+    try {
+      if (workspaceId) {
+        const workspaceCacheKey = `workspace:${workspaceId}`
+        await this.cacheAdapter.delete(workspaceCacheKey)
+        logger.debug(`Cleared MCP tool cache for workspace ${workspaceId}`)
+      } else {
+        await this.cacheAdapter.clear()
+        logger.debug('Cleared all MCP tool cache')
+      }
+    } catch (error) {
+      logger.warn('Failed to clear cache:', error)
     }
   }
 }

apps/sim/lib/mcp/storage/adapter.ts

@@ -0,0 +1,14 @@
+import type { McpTool } from '@/lib/mcp/types'
+
+export interface McpCacheEntry {
+  tools: McpTool[]
+  expiry: number // Unix timestamp ms
+}
+
+export interface McpCacheStorageAdapter {
+  get(key: string): Promise<McpCacheEntry | null>
+  set(key: string, tools: McpTool[], ttlMs: number): Promise<void>
+  delete(key: string): Promise<void>
+  clear(): Promise<void>
+  dispose(): void
+}

apps/sim/lib/mcp/storage/factory.ts

@@ -0,0 +1,53 @@
+import { getRedisClient } from '@/lib/core/config/redis'
+import { createLogger } from '@/lib/logs/console/logger'
+import type { McpCacheStorageAdapter } from './adapter'
+import { MemoryMcpCache } from './memory-cache'
+import { RedisMcpCache } from './redis-cache'
+
+const logger = createLogger('McpCacheFactory')
+
+let cachedAdapter: McpCacheStorageAdapter | null = null
+
+/**
+ * Create MCP cache storage adapter.
+ * Uses Redis if available, falls back to in-memory cache.
+ *
+ * Unlike rate-limiting (which fails if Redis is configured but unavailable),
+ * MCP caching gracefully falls back to memory since it's an optimization.
+ */
+export function createMcpCacheAdapter(): McpCacheStorageAdapter {
+  if (cachedAdapter) {
+    return cachedAdapter
+  }
+
+  const redis = getRedisClient()
+
+  if (redis) {
+    logger.info('MCP cache: Using Redis')
+    cachedAdapter = new RedisMcpCache(redis)
+  } else {
+    logger.info('MCP cache: Using in-memory (Redis not configured)')
+    cachedAdapter = new MemoryMcpCache()
+  }
+
+  return cachedAdapter
+}
+
+/**
+ * Get the current adapter type for logging/debugging
+ */
+export function getMcpCacheType(): 'redis' | 'memory' {
+  const redis = getRedisClient()
+  return redis ? 'redis' : 'memory'
+}
+
+/**
+ * Reset the cached adapter.
+ * Only use for testing purposes.
+ */
+export function resetMcpCacheAdapter(): void {
+  if (cachedAdapter) {
+    cachedAdapter.dispose()
+    cachedAdapter = null
+  }
+}

apps/sim/lib/mcp/storage/index.ts

@@ -0,0 +1,4 @@
+export type { McpCacheEntry, McpCacheStorageAdapter } from './adapter'
+export { createMcpCacheAdapter, getMcpCacheType, resetMcpCacheAdapter } from './factory'
+export { MemoryMcpCache } from './memory-cache'
+export { RedisMcpCache } from './redis-cache'

apps/sim/lib/mcp/storage/memory-cache.ts

@@ -0,0 +1,103 @@
+import { createLogger } from '@/lib/logs/console/logger'
+import type { McpTool } from '@/lib/mcp/types'
+import { MCP_CONSTANTS } from '@/lib/mcp/utils'
+import type { McpCacheEntry, McpCacheStorageAdapter } from './adapter'
+
+const logger = createLogger('McpMemoryCache')
+
+export class MemoryMcpCache implements McpCacheStorageAdapter {
+  private cache = new Map<string, McpCacheEntry>()
+  private readonly maxCacheSize = MCP_CONSTANTS.MAX_CACHE_SIZE
+  private cleanupInterval: NodeJS.Timeout | null = null
+
+  constructor() {
+    this.startPeriodicCleanup()
+  }
+
+  private startPeriodicCleanup(): void {
+    this.cleanupInterval = setInterval(
+      () => {
+        this.cleanupExpiredEntries()
+      },
+      5 * 60 * 1000 // 5 minutes
+    )
+    // Don't keep Node process alive just for cache cleanup
+    this.cleanupInterval.unref()
+  }
+
+  private cleanupExpiredEntries(): void {
+    const now = Date.now()
+    const expiredKeys: string[] = []
+
+    this.cache.forEach((entry, key) => {
+      if (entry.expiry <= now) {
+        expiredKeys.push(key)
+      }
+    })
+
+    expiredKeys.forEach((key) => this.cache.delete(key))
+
+    if (expiredKeys.length > 0) {
+      logger.debug(`Cleaned up ${expiredKeys.length} expired cache entries`)
+    }
+  }
+
+  private evictIfNeeded(): void {
+    if (this.cache.size <= this.maxCacheSize) {
+      return
+    }
+
+    // Evict oldest entries (by insertion order - Map maintains order)
+    const entriesToRemove = this.cache.size - this.maxCacheSize
+    const keys = Array.from(this.cache.keys()).slice(0, entriesToRemove)
+    keys.forEach((key) => this.cache.delete(key))
+
+    logger.debug(`Evicted ${entriesToRemove} cache entries`)
+  }
+
+  async get(key: string): Promise<McpCacheEntry | null> {
+    const entry = this.cache.get(key)
+    const now = Date.now()
+
+    if (!entry || entry.expiry <= now) {
+      if (entry) {
+        this.cache.delete(key)
+      }
+      return null
+    }
+
+    // Return copy to prevent caller from mutating cache
+    return {
+      tools: entry.tools,
+      expiry: entry.expiry,
+    }
+  }
+
+  async set(key: string, tools: McpTool[], ttlMs: number): Promise<void> {
+    const now = Date.now()
+    const entry: McpCacheEntry = {
+      tools,
+      expiry: now + ttlMs,
+    }
+
+    this.cache.set(key, entry)
+    this.evictIfNeeded()
+  }
+
+  async delete(key: string): Promise<void> {
+    this.cache.delete(key)
+  }
+
+  async clear(): Promise<void> {
+    this.cache.clear()
+  }
+
+  dispose(): void {
+    if (this.cleanupInterval) {
+      clearInterval(this.cleanupInterval)
+      this.cleanupInterval = null
+    }
+    this.cache.clear()
+    logger.info('Memory cache disposed')
+  }
+}

apps/sim/lib/mcp/storage/redis-cache.ts

@@ -0,0 +1,96 @@
+import type Redis from 'ioredis'
+import { createLogger } from '@/lib/logs/console/logger'
+import type { McpTool } from '@/lib/mcp/types'
+import type { McpCacheEntry, McpCacheStorageAdapter } from './adapter'
+
+const logger = createLogger('McpRedisCache')
+
+const REDIS_KEY_PREFIX = 'mcp:tools:'
+
+export class RedisMcpCache implements McpCacheStorageAdapter {
+  constructor(private redis: Redis) {}
+
+  private getKey(key: string): string {
+    return `${REDIS_KEY_PREFIX}${key}`
+  }
+
+  async get(key: string): Promise<McpCacheEntry | null> {
+    try {
+      const redisKey = this.getKey(key)
+      const data = await this.redis.get(redisKey)
+
+      if (!data) {
+        return null
+      }
+
+      try {
+        return JSON.parse(data) as McpCacheEntry
+      } catch {
+        // Corrupted data - delete and treat as miss
+        logger.warn('Corrupted cache entry, deleting:', redisKey)
+        await this.redis.del(redisKey)
+        return null
+      }
+    } catch (error) {
+      logger.error('Redis cache get error:', error)
+      throw error
+    }
+  }
+
+  async set(key: string, tools: McpTool[], ttlMs: number): Promise<void> {
+    try {
+      const now = Date.now()
+      const entry: McpCacheEntry = {
+        tools,
+        expiry: now + ttlMs,
+      }
+
+      await this.redis.set(this.getKey(key), JSON.stringify(entry), 'PX', ttlMs)
+    } catch (error) {
+      logger.error('Redis cache set error:', error)
+      throw error
+    }
+  }
+
+  async delete(key: string): Promise<void> {
+    try {
+      await this.redis.del(this.getKey(key))
+    } catch (error) {
+      logger.error('Redis cache delete error:', error)
+      throw error
+    }
+  }
+
+  async clear(): Promise<void> {
+    try {
+      let cursor = '0'
+      let deletedCount = 0
+
+      do {
+        const [nextCursor, keys] = await this.redis.scan(
+          cursor,
+          'MATCH',
+          `${REDIS_KEY_PREFIX}*`,
+          'COUNT',
+          100
+        )
+        cursor = nextCursor
+
+        if (keys.length > 0) {
+          await this.redis.del(...keys)
+          deletedCount += keys.length
+        }
+      } while (cursor !== '0')
+
+      logger.debug(`Cleared ${deletedCount} MCP cache entries from Redis`)
+    } catch (error) {
+      logger.error('Redis cache clear error:', error)
+      throw error
+    }
+  }
+
+  dispose(): void {
+    // Redis client is managed externally, nothing to dispose
+    logger.info('Redis cache adapter disposed')
+  }
+}

apps/sim/lib/mcp/tool-validation.ts

@@ -0,0 +1,129 @@
+/**
+ * MCP Tool Validation
+ *
+ * Shared logic for detecting issues with MCP tools across the platform.
+ * Used by both tool-input.tsx (workflow context) and MCP modal (workspace context).
+ */
+
+import isEqual from 'lodash/isEqual'
+import omit from 'lodash/omit'
+
+export type McpToolIssueType =
+  | 'server_not_found'
+  | 'server_error'
+  | 'tool_not_found'
+  | 'schema_changed'
+  | 'url_changed'
+
+export interface McpToolIssue {
+  type: McpToolIssueType
+  message: string
+}
+
+export interface StoredMcpTool {
+  serverId: string
+  serverUrl?: string
+  toolName: string
+  schema?: Record<string, unknown>
+}
+
+export interface ServerState {
+  id: string
+  url?: string
+  connectionStatus?: 'connected' | 'disconnected' | 'error'
+  lastError?: string
+}
+
+export interface DiscoveredTool {
+  serverId: string
+  name: string
+  inputSchema?: Record<string, unknown>
+}
+
+/**
+ * Compares two schemas to detect changes.
+ * Uses lodash isEqual for deep, key-order-independent comparison.
+ * Ignores description field which may be backfilled.
+ */
+export function hasSchemaChanged(
+  storedSchema: Record<string, unknown> | undefined,
+  serverSchema: Record<string, unknown> | undefined
+): boolean {
+  if (!storedSchema || !serverSchema) return false
+
+  const storedWithoutDesc = omit(storedSchema, 'description')
+  const serverWithoutDesc = omit(serverSchema, 'description')
+
+  return !isEqual(storedWithoutDesc, serverWithoutDesc)
+}
+
+/**
+ * Detects issues with a stored MCP tool by comparing against current server/tool state.
+ */
+export function getMcpToolIssue(
+  storedTool: StoredMcpTool,
+  servers: ServerState[],
+  discoveredTools: DiscoveredTool[]
+): McpToolIssue | null {
+  const { serverId, serverUrl, toolName, schema } = storedTool
+
+  // Check server exists
+  const server = servers.find((s) => s.id === serverId)
+  if (!server) {
+    return { type: 'server_not_found', message: 'Server not found' }
+  }
+
+  // Check server connection status
+  if (server.connectionStatus === 'error') {
+    return { type: 'server_error', message: server.lastError || 'Server connection error' }
+  }
+  if (server.connectionStatus !== 'connected') {
+    return { type: 'server_error', message: 'Server not connected' }
+  }
+
+  // Check server URL changed (if we have stored URL)
+  if (serverUrl && server.url && serverUrl !== server.url) {
+    return { type: 'url_changed', message: 'Server URL changed - tools may be different' }
+  }
+
+  // Check tool exists on server
+  const serverTool = discoveredTools.find((t) => t.serverId === serverId && t.name === toolName)
+  if (!serverTool) {
+    return { type: 'tool_not_found', message: 'Tool not found on server' }
+  }
+
+  // Check schema changed
+  if (schema && serverTool.inputSchema) {
+    if (hasSchemaChanged(schema, serverTool.inputSchema)) {
+      return { type: 'schema_changed', message: 'Tool schema changed' }
+    }
+  }
+
+  return null
+}
+
+/**
+ * Returns a user-friendly label for the issue badge
+ */
+export function getIssueBadgeLabel(issue: McpToolIssue): string {
+  switch (issue.type) {
+    case 'schema_changed':
+      return 'stale'
+    case 'url_changed':
+      return 'stale'
+    default:
+      return 'unavailable'
+  }
+}
+
+/**
+ * Checks if an issue means the tool cannot be used (vs just being stale)
+ */
+export function isToolUnavailable(issue: McpToolIssue | null): boolean {
+  if (!issue) return false
+  return (
+    issue.type === 'server_not_found' ||
+    issue.type === 'server_error' ||
+    issue.type === 'tool_not_found'
+  )
+}

apps/sim/lib/mcp/types.ts

@@ -6,6 +6,11 @@
 // Modern MCP uses Streamable HTTP which handles both HTTP POST and SSE responses
 export type McpTransport = 'streamable-http'
 
+export interface McpServerStatusConfig {
+  consecutiveFailures: number
+  lastSuccessfulDiscovery: string | null
+}
+
 export interface McpServerConfig {
   id: string
   name: string
@@ -20,6 +25,7 @@ export interface McpServerConfig {
   timeout?: number
   retries?: number
   enabled?: boolean
+  statusConfig?: McpServerStatusConfig
   createdAt?: string
   updatedAt?: string
 }
@@ -113,8 +119,8 @@ export class McpError extends Error {
 }
 
 export class McpConnectionError extends McpError {
-  constructor(message: string, serverId: string) {
-    super(`MCP Connection Error for server ${serverId}: ${message}`)
+  constructor(message: string, serverName: string) {
+    super(`Failed to connect to "${serverName}": ${message}`)
     this.name = 'McpConnectionError'
   }
 }

apps/sim/lib/mcp/utils.ts

@@ -6,10 +6,11 @@ import type { McpApiResponse } from '@/lib/mcp/types'
  */
 export const MCP_CONSTANTS = {
   EXECUTION_TIMEOUT: 60000,
-  CACHE_TIMEOUT: 30 * 1000,
+  CACHE_TIMEOUT: 5 * 60 * 1000, // 5 minutes
   DEFAULT_RETRIES: 3,
   DEFAULT_CONNECTION_TIMEOUT: 30000,
   MAX_CACHE_SIZE: 1000,
+  MAX_CONSECUTIVE_FAILURES: 3,
 } as const
 
 /**

apps/sim/providers/utils.ts

@@ -1001,7 +1001,7 @@ export function supportsToolUsageControl(provider: string): boolean {
  * Prepare tool execution parameters, separating tool parameters from system parameters
  */
 export function prepareToolExecution(
-  tool: { params?: Record<string, any> },
+  tool: { params?: Record<string, any>; parameters?: Record<string, any> },
   llmArgs: Record<string, any>,
   request: {
     workflowId?: string
@@ -1051,6 +1051,8 @@ export function prepareToolExecution(
     ...(request.workflowVariables ? { workflowVariables: request.workflowVariables } : {}),
     ...(request.blockData ? { blockData: request.blockData } : {}),
     ...(request.blockNameMapping ? { blockNameMapping: request.blockNameMapping } : {}),
+    // Pass tool schema for MCP tools to skip discovery
+    ...(tool.parameters ? { _toolSchema: tool.parameters } : {}),
   }
 
   return { toolParams, executionParams }

apps/sim/stores/settings-modal/store.ts

@@ -0,0 +1,51 @@
+'use client'
+
+import { create } from 'zustand'
+
+type SettingsSection =
+  | 'general'
+  | 'environment'
+  | 'template-profile'
+  | 'integrations'
+  | 'apikeys'
+  | 'files'
+  | 'subscription'
+  | 'team'
+  | 'sso'
+  | 'copilot'
+  | 'mcp'
+  | 'custom-tools'
+
+interface SettingsModalState {
+  isOpen: boolean
+  initialSection: SettingsSection | null
+  mcpServerId: string | null
+
+  openModal: (options?: { section?: SettingsSection; mcpServerId?: string }) => void
+  closeModal: () => void
+  clearInitialState: () => void
+}
+
+export const useSettingsModalStore = create<SettingsModalState>((set) => ({
+  isOpen: false,
+  initialSection: null,
+  mcpServerId: null,
+
+  openModal: (options) =>
+    set({
+      isOpen: true,
+      initialSection: options?.section || null,
+      mcpServerId: options?.mcpServerId || null,
+    }),
+
+  closeModal: () =>
+    set({
+      isOpen: false,
+    }),
+
+  clearInitialState: () =>
+    set({
+      initialSection: null,
+      mcpServerId: null,
+    }),
+}))

apps/sim/tools/index.ts

@@ -107,6 +107,7 @@ const MCP_SYSTEM_PARAMETERS = new Set([
   'workflowVariables',
   'blockData',
   'blockNameMapping',
+  '_toolSchema',
 ])
 
 /**
@@ -979,7 +980,10 @@ async function executeMcpTool(
       }
     }
 
-    const requestBody = {
+    // Get tool schema if provided (from agent block's cached schema)
+    const toolSchema = params._toolSchema
+
+    const requestBody: Record<string, any> = {
       serverId,
       toolName,
       arguments: toolArguments,
@@ -987,6 +991,11 @@ async function executeMcpTool(
       workspaceId, // Pass workspace context for scoping
     }
 
+    // Include schema to skip discovery on execution
+    if (toolSchema) {
+      requestBody.toolSchema = toolSchema
+    }
+
     const body = JSON.stringify(requestBody)
 
     // Check request body size before sending
@@ -995,6 +1004,7 @@ async function executeMcpTool(
     logger.info(`[${actualRequestId}] Making MCP tool request to ${toolName} on ${serverId}`, {
       hasWorkspaceId: !!workspaceId,
       hasWorkflowId: !!workflowId,
+      hasToolSchema: !!toolSchema,
     })
 
     const response = await fetch(`${baseUrl}/api/mcp/tools/execute`, {

packages/db/migrations/0123_windy_lockheed.sql

@@ -0,0 +1 @@
+ALTER TABLE "mcp_servers" ADD COLUMN "status_config" jsonb DEFAULT '{}';

packages/db/migrations/meta/_journal.json

@@ -855,6 +855,13 @@
       "when": 1765587157593,
       "tag": "0122_pale_absorbing_man",
       "breakpoints": true
+    },
+    {
+      "idx": 123,
+      "version": "7",
+      "when": 1765932898404,
+      "tag": "0123_windy_lockheed",
+      "breakpoints": true
     }
   ]
 }

packages/db/schema.ts

@@ -1547,6 +1547,8 @@ export const mcpServers = pgTable(
     connectionStatus: text('connection_status').default('disconnected'),
     lastError: text('last_error'),
 
+    statusConfig: jsonb('status_config').default('{}'),
+
     toolCount: integer('tool_count').default(0),
     lastToolsRefresh: timestamp('last_tools_refresh'),
     totalRequests: integer('total_requests').default(0),