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

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>
+        )
+      })}
     </>
   )
 }