feat(workflow-as-mcp): wrapping workflows in the same workspace as MCP tools to particular MCP servers

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

@@ -0,0 +1,88 @@
+import { db } from '@sim/db'
+import { permissions, workflowMcpServer, workspace } from '@sim/db/schema'
+import { and, eq, sql } from 'drizzle-orm'
+import { type NextRequest, NextResponse } from 'next/server'
+import { checkHybridAuth } from '@/lib/auth/hybrid'
+import { getBaseUrl } from '@/lib/core/utils/urls'
+import { createLogger } from '@/lib/logs/console/logger'
+
+const logger = createLogger('McpDiscoverAPI')
+
+export const dynamic = 'force-dynamic'
+
+/**
+ * Discover all MCP servers available to the authenticated user.
+ */
+export async function GET(request: NextRequest) {
+  try {
+    const auth = await checkHybridAuth(request, { requireWorkflowId: false })
+
+    if (!auth.success || !auth.userId) {
+      return NextResponse.json(
+        { success: false, error: 'Authentication required. Provide X-API-Key header.' },
+        { status: 401 }
+      )
+    }
+
+    const userId = auth.userId
+
+    const userWorkspacePermissions = await db
+      .select({ entityId: permissions.entityId })
+      .from(permissions)
+      .where(and(eq(permissions.userId, userId), eq(permissions.entityType, 'workspace')))
+
+    const workspaceIds = userWorkspacePermissions.map((w) => w.entityId)
+
+    if (workspaceIds.length === 0) {
+      return NextResponse.json({ success: true, servers: [] })
+    }
+
+    const servers = await db
+      .select({
+        id: workflowMcpServer.id,
+        name: workflowMcpServer.name,
+        description: workflowMcpServer.description,
+        workspaceId: workflowMcpServer.workspaceId,
+        workspaceName: workspace.name,
+        createdAt: workflowMcpServer.createdAt,
+        toolCount: sql<number>`(
+          SELECT COUNT(*)::int 
+          FROM "workflow_mcp_tool" 
+          WHERE "workflow_mcp_tool"."server_id" = "workflow_mcp_server"."id"
+        )`.as('tool_count'),
+      })
+      .from(workflowMcpServer)
+      .leftJoin(workspace, eq(workflowMcpServer.workspaceId, workspace.id))
+      .where(sql`${workflowMcpServer.workspaceId} IN ${workspaceIds}`)
+      .orderBy(workflowMcpServer.name)
+
+    const baseUrl = getBaseUrl()
+
+    const formattedServers = servers.map((server) => ({
+      id: server.id,
+      name: server.name,
+      description: server.description,
+      workspace: { id: server.workspaceId, name: server.workspaceName },
+      toolCount: server.toolCount || 0,
+      createdAt: server.createdAt,
+      url: `${baseUrl}/api/mcp/serve/${server.id}`,
+    }))
+
+    logger.info(`User ${userId} discovered ${formattedServers.length} MCP servers`)
+
+    return NextResponse.json({
+      success: true,
+      servers: formattedServers,
+      authentication: {
+        method: 'API Key',
+        header: 'X-API-Key',
+      },
+    })
+  } catch (error) {
+    logger.error('Error discovering MCP servers:', error)
+    return NextResponse.json(
+      { success: false, error: 'Failed to discover MCP servers' },
+      { status: 500 }
+    )
+  }
+}

apps/sim/app/api/mcp/serve/[serverId]/route.ts

@@ -0,0 +1,306 @@
+/**
+ * MCP Serve Endpoint - Implements MCP protocol for workflow servers using SDK types.
+ */
+
+import {
+  type CallToolResult,
+  ErrorCode,
+  type InitializeResult,
+  isJSONRPCNotification,
+  isJSONRPCRequest,
+  type JSONRPCError,
+  type JSONRPCMessage,
+  type JSONRPCResponse,
+  type ListToolsResult,
+  type RequestId,
+} from '@modelcontextprotocol/sdk/types.js'
+import { db } from '@sim/db'
+import { workflow, workflowMcpServer, workflowMcpTool } from '@sim/db/schema'
+import { eq } from 'drizzle-orm'
+import { type NextRequest, NextResponse } from 'next/server'
+import { checkHybridAuth } from '@/lib/auth/hybrid'
+import { getBaseUrl } from '@/lib/core/utils/urls'
+import { createLogger } from '@/lib/logs/console/logger'
+
+const logger = createLogger('WorkflowMcpServeAPI')
+
+export const dynamic = 'force-dynamic'
+
+interface RouteParams {
+  serverId: string
+}
+
+function createResponse(id: RequestId, result: unknown): JSONRPCResponse {
+  return {
+    jsonrpc: '2.0',
+    id,
+    result: result as JSONRPCResponse['result'],
+  }
+}
+
+function createError(id: RequestId, code: ErrorCode | number, message: string): JSONRPCError {
+  return {
+    jsonrpc: '2.0',
+    id,
+    error: { code, message },
+  }
+}
+
+async function getServer(serverId: string) {
+  const [server] = await db
+    .select({
+      id: workflowMcpServer.id,
+      name: workflowMcpServer.name,
+      workspaceId: workflowMcpServer.workspaceId,
+    })
+    .from(workflowMcpServer)
+    .where(eq(workflowMcpServer.id, serverId))
+    .limit(1)
+
+  return server
+}
+
+export async function GET(request: NextRequest, { params }: { params: Promise<RouteParams> }) {
+  const { serverId } = await params
+
+  try {
+    const server = await getServer(serverId)
+    if (!server) {
+      return NextResponse.json({ error: 'Server not found' }, { status: 404 })
+    }
+
+    return NextResponse.json({
+      name: server.name,
+      version: '1.0.0',
+      protocolVersion: '2024-11-05',
+      capabilities: { tools: {} },
+    })
+  } catch (error) {
+    logger.error('Error getting MCP server info:', error)
+    return NextResponse.json({ error: 'Internal server error' }, { status: 500 })
+  }
+}
+
+export async function POST(request: NextRequest, { params }: { params: Promise<RouteParams> }) {
+  const { serverId } = await params
+
+  try {
+    const server = await getServer(serverId)
+    if (!server) {
+      return NextResponse.json({ error: 'Server not found' }, { status: 404 })
+    }
+
+    const auth = await checkHybridAuth(request, { requireWorkflowId: false })
+    if (!auth.success || !auth.userId) {
+      return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
+    }
+
+    const body = await request.json()
+    const message = body as JSONRPCMessage
+
+    if (isJSONRPCNotification(message)) {
+      logger.info(`Received notification: ${message.method}`)
+      return new NextResponse(null, { status: 202 })
+    }
+
+    if (!isJSONRPCRequest(message)) {
+      return NextResponse.json(
+        createError(0, ErrorCode.InvalidRequest, 'Invalid JSON-RPC message'),
+        {
+          status: 400,
+        }
+      )
+    }
+
+    const { id, method, params: rpcParams } = message
+    const apiKey =
+      request.headers.get('X-API-Key') ||
+      request.headers.get('Authorization')?.replace('Bearer ', '')
+
+    switch (method) {
+      case 'initialize': {
+        const result: InitializeResult = {
+          protocolVersion: '2024-11-05',
+          capabilities: { tools: {} },
+          serverInfo: { name: server.name, version: '1.0.0' },
+        }
+        return NextResponse.json(createResponse(id, result))
+      }
+
+      case 'ping':
+        return NextResponse.json(createResponse(id, {}))
+
+      case 'tools/list':
+        return handleToolsList(id, serverId)
+
+      case 'tools/call':
+        return handleToolsCall(
+          id,
+          serverId,
+          rpcParams as { name: string; arguments?: Record<string, unknown> },
+          apiKey
+        )
+
+      default:
+        return NextResponse.json(
+          createError(id, ErrorCode.MethodNotFound, `Method not found: ${method}`),
+          {
+            status: 404,
+          }
+        )
+    }
+  } catch (error) {
+    logger.error('Error handling MCP request:', error)
+    return NextResponse.json(createError(0, ErrorCode.InternalError, 'Internal error'), {
+      status: 500,
+    })
+  }
+}
+
+async function handleToolsList(id: RequestId, serverId: string): Promise<NextResponse> {
+  try {
+    const tools = await db
+      .select({
+        toolName: workflowMcpTool.toolName,
+        toolDescription: workflowMcpTool.toolDescription,
+        parameterSchema: workflowMcpTool.parameterSchema,
+      })
+      .from(workflowMcpTool)
+      .where(eq(workflowMcpTool.serverId, serverId))
+
+    const result: ListToolsResult = {
+      tools: tools.map((tool) => {
+        const schema = tool.parameterSchema as {
+          type?: string
+          properties?: Record<string, unknown>
+          required?: string[]
+        } | null
+        return {
+          name: tool.toolName,
+          description: tool.toolDescription || `Execute workflow: ${tool.toolName}`,
+          inputSchema: {
+            type: 'object' as const,
+            properties: schema?.properties || {},
+            ...(schema?.required && schema.required.length > 0 && { required: schema.required }),
+          },
+        }
+      }),
+    }
+
+    return NextResponse.json(createResponse(id, result))
+  } catch (error) {
+    logger.error('Error listing tools:', error)
+    return NextResponse.json(createError(id, ErrorCode.InternalError, 'Failed to list tools'), {
+      status: 500,
+    })
+  }
+}
+
+async function handleToolsCall(
+  id: RequestId,
+  serverId: string,
+  params: { name: string; arguments?: Record<string, unknown> } | undefined,
+  apiKey?: string | null
+): Promise<NextResponse> {
+  try {
+    if (!params?.name) {
+      return NextResponse.json(createError(id, ErrorCode.InvalidParams, 'Tool name required'), {
+        status: 400,
+      })
+    }
+
+    const tools = await db
+      .select({
+        toolName: workflowMcpTool.toolName,
+        workflowId: workflowMcpTool.workflowId,
+      })
+      .from(workflowMcpTool)
+      .where(eq(workflowMcpTool.serverId, serverId))
+
+    const tool = tools.find((t) => t.toolName === params.name)
+    if (!tool) {
+      return NextResponse.json(
+        createError(id, ErrorCode.InvalidParams, `Tool not found: ${params.name}`),
+        {
+          status: 404,
+        }
+      )
+    }
+
+    const [wf] = await db
+      .select({ isDeployed: workflow.isDeployed })
+      .from(workflow)
+      .where(eq(workflow.id, tool.workflowId))
+      .limit(1)
+
+    if (!wf?.isDeployed) {
+      return NextResponse.json(
+        createError(id, ErrorCode.InternalError, 'Workflow is not deployed'),
+        {
+          status: 400,
+        }
+      )
+    }
+
+    const executeUrl = `${getBaseUrl()}/api/workflows/${tool.workflowId}/execute`
+    const headers: Record<string, string> = { 'Content-Type': 'application/json' }
+    if (apiKey) headers['X-API-Key'] = apiKey
+
+    logger.info(`Executing workflow ${tool.workflowId} via MCP tool ${params.name}`)
+
+    const response = await fetch(executeUrl, {
+      method: 'POST',
+      headers,
+      body: JSON.stringify({ input: params.arguments || {}, triggerType: 'mcp' }),
+    })
+
+    const executeResult = await response.json()
+
+    if (!response.ok) {
+      return NextResponse.json(
+        createError(
+          id,
+          ErrorCode.InternalError,
+          executeResult.error || 'Workflow execution failed'
+        ),
+        { status: 500 }
+      )
+    }
+
+    const result: CallToolResult = {
+      content: [
+        { type: 'text', text: JSON.stringify(executeResult.output || executeResult, null, 2) },
+      ],
+      isError: !executeResult.success,
+    }
+
+    return NextResponse.json(createResponse(id, result))
+  } catch (error) {
+    logger.error('Error calling tool:', error)
+    return NextResponse.json(createError(id, ErrorCode.InternalError, 'Tool execution failed'), {
+      status: 500,
+    })
+  }
+}
+
+export async function DELETE(request: NextRequest, { params }: { params: Promise<RouteParams> }) {
+  const { serverId } = await params
+
+  try {
+    const server = await getServer(serverId)
+    if (!server) {
+      return NextResponse.json({ error: 'Server not found' }, { status: 404 })
+    }
+
+    const auth = await checkHybridAuth(request, { requireWorkflowId: false })
+    if (!auth.success || !auth.userId) {
+      return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
+    }
+
+    logger.info(`MCP session terminated for server ${serverId}`)
+    return new NextResponse(null, { status: 204 })
+  } catch (error) {
+    logger.error('Error handling MCP DELETE request:', error)
+    return NextResponse.json({ error: 'Internal server error' }, { status: 500 })
+  }
+}