feat(copilot): copilot mcp + server side copilot execution (#3173)

* v0 * v1 * Basic ss tes * Ss tests * Stuff * Add mcp * mcp v1 * Improvement * Fix * BROKEN * Checkpoint * Streaming * Fix abort * Things are broken * Streaming seems to work but copilot is dumb * Fix edge issue * LUAAAA * Fix stream buffer * Fix lint * Checkpoint * Initial temp state, in the middle of a refactor * Initial test shows diff store still working * Tool refactor * First cleanup pass complete - untested * Continued cleanup * Refactor * Refactor complete - no testing yet * Fix - cursor makes me sad * Fix mcp * Clean up mcp * Updated mcp * Add respond to subagents * Fix definitions * Add tools * Add tools * Add copilot mcp tracking * Fix lint * Fix mcp * Fix * Updates * Clean up mcp * Fix copilot mcp tool names to be sim prefixed * Add opus 4.6 * Fix discovery tool * Fix * Remove logs * Fix go side tool rendering * Update docs * Fix hydration * Fix tool call resolution * Fix * Fix lint * Fix superagent and autoallow integrations * Fix always allow * Update block * Remove plan docs * Fix hardcoded ff * Fix dropped provider * Fix lint * Fix tests * Fix dead messages array * Fix discovery * Fix run workflow * Fix run block * Fix run from block in copilot * Fix lint * Fix skip and mtb * Fix typing * Fix tool call * Bump api version * Fix bun lock * Nuke bad files
2026-02-11 23:14:58 -05:00 · 2026-02-09 19:33:29 -08:00
parent e5d30494cb
commit 190f12fd77
199 changed files with 29113 additions and 16699 deletions
--- a/apps/sim/app/api/billing/update-cost/route.ts
+++ b/apps/sim/app/api/billing/update-cost/route.ts
@@ -18,6 +18,7 @@ const UpdateCostSchema = z.object({
  model: z.string().min(1, 'Model is required'),
  inputTokens: z.number().min(0).default(0),
  outputTokens: z.number().min(0).default(0),
+  source: z.enum(['copilot', 'mcp_copilot']).default('copilot'),
 })

 /**
@@ -75,12 +76,14 @@ export async function POST(req: NextRequest) {
      )
    }

-    const { userId, cost, model, inputTokens, outputTokens } = validation.data
+    const { userId, cost, model, inputTokens, outputTokens, source } = validation.data
+    const isMcp = source === 'mcp_copilot'

    logger.info(`[${requestId}] Processing cost update`, {
      userId,
      cost,
      model,
+      source,
    })

    // Check if user stats record exists (same as ExecutionLogger)
@@ -96,7 +99,7 @@ export async function POST(req: NextRequest) {
      return NextResponse.json({ error: 'User stats record not found' }, { status: 500 })
    }

-    const updateFields = {
+    const updateFields: Record<string, unknown> = {
      totalCost: sql`total_cost + ${cost}`,
      currentPeriodCost: sql`current_period_cost + ${cost}`,
      totalCopilotCost: sql`total_copilot_cost + ${cost}`,
@@ -105,17 +108,24 @@ export async function POST(req: NextRequest) {
      lastActive: new Date(),
    }

+    // Also increment MCP-specific counters when source is mcp_copilot
+    if (isMcp) {
+      updateFields.totalMcpCopilotCost = sql`total_mcp_copilot_cost + ${cost}`
+      updateFields.currentPeriodMcpCopilotCost = sql`current_period_mcp_copilot_cost + ${cost}`
+    }
+
    await db.update(userStats).set(updateFields).where(eq(userStats.userId, userId))

    logger.info(`[${requestId}] Updated user stats record`, {
      userId,
      addedCost: cost,
+      source,
    })

    // Log usage for complete audit trail
    await logModelUsage({
      userId,
-      source: 'copilot',
+      source: isMcp ? 'mcp_copilot' : 'copilot',
      model,
      inputTokens,
      outputTokens,
--- a/apps/sim/app/api/copilot/api-keys/generate/route.ts
+++ b/apps/sim/app/api/copilot/api-keys/generate/route.ts
@@ -1,7 +1,7 @@
 import { type NextRequest, NextResponse } from 'next/server'
 import { z } from 'zod'
 import { getSession } from '@/lib/auth'
-import { SIM_AGENT_API_URL_DEFAULT } from '@/lib/copilot/constants'
+import { SIM_AGENT_API_URL } from '@/lib/copilot/constants'
 import { env } from '@/lib/core/config/env'

 const GenerateApiKeySchema = z.object({
@@ -17,9 +17,6 @@ export async function POST(req: NextRequest) {

    const userId = session.user.id

-    // Move environment variable access inside the function
-    const SIM_AGENT_API_URL = env.SIM_AGENT_API_URL || SIM_AGENT_API_URL_DEFAULT
-
    const body = await req.json().catch(() => ({}))
    const validationResult = GenerateApiKeySchema.safeParse(body)

--- a/apps/sim/app/api/copilot/api-keys/route.test.ts
+++ b/apps/sim/app/api/copilot/api-keys/route.test.ts
@@ -19,6 +19,7 @@ describe('Copilot API Keys API Route', () => {

    vi.doMock('@/lib/copilot/constants', () => ({
      SIM_AGENT_API_URL_DEFAULT: 'https://agent.sim.example.com',
+      SIM_AGENT_API_URL: 'https://agent.sim.example.com',
    }))

    vi.doMock('@/lib/core/config/env', async () => {
--- a/apps/sim/app/api/copilot/api-keys/route.ts
+++ b/apps/sim/app/api/copilot/api-keys/route.ts
@@ -1,6 +1,6 @@
 import { type NextRequest, NextResponse } from 'next/server'
 import { getSession } from '@/lib/auth'
-import { SIM_AGENT_API_URL_DEFAULT } from '@/lib/copilot/constants'
+import { SIM_AGENT_API_URL } from '@/lib/copilot/constants'
 import { env } from '@/lib/core/config/env'

 export async function GET(request: NextRequest) {
@@ -12,8 +12,6 @@ export async function GET(request: NextRequest) {

    const userId = session.user.id

-    const SIM_AGENT_API_URL = env.SIM_AGENT_API_URL || SIM_AGENT_API_URL_DEFAULT
-
    const res = await fetch(`${SIM_AGENT_API_URL}/api/validate-key/get-api-keys`, {
      method: 'POST',
      headers: {
@@ -68,8 +66,6 @@ export async function DELETE(request: NextRequest) {
      return NextResponse.json({ error: 'id is required' }, { status: 400 })
    }

-    const SIM_AGENT_API_URL = env.SIM_AGENT_API_URL || SIM_AGENT_API_URL_DEFAULT
-
    const res = await fetch(`${SIM_AGENT_API_URL}/api/validate-key/delete`, {
      method: 'POST',
      headers: {
--- a/apps/sim/app/api/copilot/chat/route.ts
+++ b/apps/sim/app/api/copilot/chat/route.ts
--- a/apps/sim/app/api/copilot/chat/stream/route.ts
+++ b/apps/sim/app/api/copilot/chat/stream/route.ts
@@ -0,0 +1,130 @@
+import { createLogger } from '@sim/logger'
+import { type NextRequest, NextResponse } from 'next/server'
+import {
+  getStreamMeta,
+  readStreamEvents,
+  type StreamMeta,
+} from '@/lib/copilot/orchestrator/stream-buffer'
+import { authenticateCopilotRequestSessionOnly } from '@/lib/copilot/request-helpers'
+import { SSE_HEADERS } from '@/lib/core/utils/sse'
+
+const logger = createLogger('CopilotChatStreamAPI')
+const POLL_INTERVAL_MS = 250
+const MAX_STREAM_MS = 10 * 60 * 1000
+
+function encodeEvent(event: Record<string, any>): Uint8Array {
+  return new TextEncoder().encode(`data: ${JSON.stringify(event)}\n\n`)
+}
+
+export async function GET(request: NextRequest) {
+  const { userId: authenticatedUserId, isAuthenticated } =
+    await authenticateCopilotRequestSessionOnly()
+
+  if (!isAuthenticated || !authenticatedUserId) {
+    return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
+  }
+
+  const url = new URL(request.url)
+  const streamId = url.searchParams.get('streamId') || ''
+  const fromParam = url.searchParams.get('from') || '0'
+  const fromEventId = Number(fromParam || 0)
+  // If batch=true, return buffered events as JSON instead of SSE
+  const batchMode = url.searchParams.get('batch') === 'true'
+  const toParam = url.searchParams.get('to')
+  const toEventId = toParam ? Number(toParam) : undefined
+
+  if (!streamId) {
+    return NextResponse.json({ error: 'streamId is required' }, { status: 400 })
+  }
+
+  const meta = (await getStreamMeta(streamId)) as StreamMeta | null
+  logger.info('[Resume] Stream lookup', {
+    streamId,
+    fromEventId,
+    toEventId,
+    batchMode,
+    hasMeta: !!meta,
+    metaStatus: meta?.status,
+  })
+  if (!meta) {
+    return NextResponse.json({ error: 'Stream not found' }, { status: 404 })
+  }
+  if (meta.userId && meta.userId !== authenticatedUserId) {
+    return NextResponse.json({ error: 'Unauthorized' }, { status: 403 })
+  }
+
+  // Batch mode: return all buffered events as JSON
+  if (batchMode) {
+    const events = await readStreamEvents(streamId, fromEventId)
+    const filteredEvents = toEventId ? events.filter((e) => e.eventId <= toEventId) : events
+    logger.info('[Resume] Batch response', {
+      streamId,
+      fromEventId,
+      toEventId,
+      eventCount: filteredEvents.length,
+    })
+    return NextResponse.json({
+      success: true,
+      events: filteredEvents,
+      status: meta.status,
+    })
+  }
+
+  const startTime = Date.now()
+
+  const stream = new ReadableStream({
+    async start(controller) {
+      let lastEventId = Number.isFinite(fromEventId) ? fromEventId : 0
+
+      const flushEvents = async () => {
+        const events = await readStreamEvents(streamId, lastEventId)
+        if (events.length > 0) {
+          logger.info('[Resume] Flushing events', {
+            streamId,
+            fromEventId: lastEventId,
+            eventCount: events.length,
+          })
+        }
+        for (const entry of events) {
+          lastEventId = entry.eventId
+          const payload = {
+            ...entry.event,
+            eventId: entry.eventId,
+            streamId: entry.streamId,
+          }
+          controller.enqueue(encodeEvent(payload))
+        }
+      }
+
+      try {
+        await flushEvents()
+
+        while (Date.now() - startTime < MAX_STREAM_MS) {
+          const currentMeta = await getStreamMeta(streamId)
+          if (!currentMeta) break
+
+          await flushEvents()
+
+          if (currentMeta.status === 'complete' || currentMeta.status === 'error') {
+            break
+          }
+
+          if (request.signal.aborted) {
+            break
+          }
+
+          await new Promise((resolve) => setTimeout(resolve, POLL_INTERVAL_MS))
+        }
+      } catch (error) {
+        logger.warn('Stream replay failed', {
+          streamId,
+          error: error instanceof Error ? error.message : String(error),
+        })
+      } finally {
+        controller.close()
+      }
+    },
+  })
+
+  return new Response(stream, { headers: SSE_HEADERS })
+}
--- a/apps/sim/app/api/copilot/confirm/route.test.ts
+++ b/apps/sim/app/api/copilot/confirm/route.test.ts
@@ -139,7 +139,6 @@ describe('Copilot Confirm API Route', () => {
        status: 'success',
      })

-      expect(mockRedisExists).toHaveBeenCalled()
      expect(mockRedisSet).toHaveBeenCalled()
    })

@@ -256,11 +255,11 @@ describe('Copilot Confirm API Route', () => {
      expect(responseData.error).toBe('Failed to update tool call status or tool call not found')
    })

-    it('should return 400 when tool call is not found in Redis', async () => {
+    it('should return 400 when Redis set fails', async () => {
      const authMocks = mockAuth()
      authMocks.setAuthenticated()

-      mockRedisExists.mockResolvedValue(0)
+      mockRedisSet.mockRejectedValueOnce(new Error('Redis set failed'))

      const req = createMockRequest('POST', {
        toolCallId: 'non-existent-tool',
@@ -279,7 +278,7 @@ describe('Copilot Confirm API Route', () => {
      const authMocks = mockAuth()
      authMocks.setAuthenticated()

-      mockRedisExists.mockRejectedValue(new Error('Redis connection failed'))
+      mockRedisSet.mockRejectedValueOnce(new Error('Redis connection failed'))

      const req = createMockRequest('POST', {
        toolCallId: 'tool-call-123',
--- a/apps/sim/app/api/copilot/confirm/route.ts
+++ b/apps/sim/app/api/copilot/confirm/route.ts
@@ -1,6 +1,7 @@
 import { createLogger } from '@sim/logger'
 import { type NextRequest, NextResponse } from 'next/server'
 import { z } from 'zod'
+import { REDIS_TOOL_CALL_PREFIX, REDIS_TOOL_CALL_TTL_SECONDS } from '@/lib/copilot/constants'
 import {
  authenticateCopilotRequestSessionOnly,
  createBadRequestResponse,
@@ -23,7 +24,8 @@ const ConfirmationSchema = z.object({
 })

 /**
- * Update tool call status in Redis
+ * Write the user's tool decision to Redis. The server-side orchestrator's
+ * waitForToolDecision() polls Redis for this value.
 */
 async function updateToolCallStatus(
  toolCallId: string,
@@ -32,57 +34,24 @@ async function updateToolCallStatus(
 ): Promise<boolean> {
  const redis = getRedisClient()
  if (!redis) {
-    logger.warn('updateToolCallStatus: Redis client not available')
+    logger.warn('Redis client not available for tool confirmation')
    return false
  }

  try {
-    const key = `tool_call:${toolCallId}`
-    const timeout = 600000 // 10 minutes timeout for user confirmation
-    const pollInterval = 100 // Poll every 100ms
-    const startTime = Date.now()
-
-    logger.info('Polling for tool call in Redis', { toolCallId, key, timeout })
-
-    // Poll until the key exists or timeout
-    while (Date.now() - startTime < timeout) {
-      const exists = await redis.exists(key)
-      if (exists) {
-        break
-      }
-
-      // Wait before next poll
-      await new Promise((resolve) => setTimeout(resolve, pollInterval))
-    }
-
-    // Final check if key exists after polling
-    const exists = await redis.exists(key)
-    if (!exists) {
-      logger.warn('Tool call not found in Redis after polling timeout', {
-        toolCallId,
-        key,
-        timeout,
-        pollDuration: Date.now() - startTime,
-      })
-      return false
-    }
-
-    // Store both status and message as JSON
-    const toolCallData = {
+    const key = `${REDIS_TOOL_CALL_PREFIX}${toolCallId}`
+    const payload = {
      status,
      message: message || null,
      timestamp: new Date().toISOString(),
    }
-
-    await redis.set(key, JSON.stringify(toolCallData), 'EX', 86400) // Keep 24 hour expiry
-
+    await redis.set(key, JSON.stringify(payload), 'EX', REDIS_TOOL_CALL_TTL_SECONDS)
    return true
  } catch (error) {
-    logger.error('Failed to update tool call status in Redis', {
+    logger.error('Failed to update tool call status', {
      toolCallId,
      status,
-      message,
-      error: error instanceof Error ? error.message : 'Unknown error',
+      error: error instanceof Error ? error.message : String(error),
    })
    return false
  }
--- a/apps/sim/app/api/copilot/credentials/route.ts
+++ b/apps/sim/app/api/copilot/credentials/route.ts
@@ -0,0 +1,28 @@
+import { type NextRequest, NextResponse } from 'next/server'
+import { authenticateCopilotRequestSessionOnly } from '@/lib/copilot/request-helpers'
+import { routeExecution } from '@/lib/copilot/tools/server/router'
+
+/**
+ * GET /api/copilot/credentials
+ * Returns connected OAuth credentials for the authenticated user.
+ * Used by the copilot store for credential masking.
+ */
+export async function GET(_req: NextRequest) {
+  const { userId, isAuthenticated } = await authenticateCopilotRequestSessionOnly()
+  if (!isAuthenticated || !userId) {
+    return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
+  }
+
+  try {
+    const result = await routeExecution('get_credentials', {}, { userId })
+    return NextResponse.json({ success: true, result })
+  } catch (error) {
+    return NextResponse.json(
+      {
+        success: false,
+        error: error instanceof Error ? error.message : 'Failed to load credentials',
+      },
+      { status: 500 }
+    )
+  }
+}
--- a/apps/sim/app/api/copilot/execute-copilot-server-tool/route.ts
+++ b/apps/sim/app/api/copilot/execute-copilot-server-tool/route.ts
@@ -1,54 +0,0 @@
-import { createLogger } from '@sim/logger'
-import { type NextRequest, NextResponse } from 'next/server'
-import { z } from 'zod'
-import {
-  authenticateCopilotRequestSessionOnly,
-  createBadRequestResponse,
-  createInternalServerErrorResponse,
-  createRequestTracker,
-  createUnauthorizedResponse,
-} from '@/lib/copilot/request-helpers'
-import { routeExecution } from '@/lib/copilot/tools/server/router'
-
-const logger = createLogger('ExecuteCopilotServerToolAPI')
-
-const ExecuteSchema = z.object({
-  toolName: z.string(),
-  payload: z.unknown().optional(),
-})
-
-export async function POST(req: NextRequest) {
-  const tracker = createRequestTracker()
-  try {
-    const { userId, isAuthenticated } = await authenticateCopilotRequestSessionOnly()
-    if (!isAuthenticated || !userId) {
-      return createUnauthorizedResponse()
-    }
-
-    const body = await req.json()
-    try {
-      const preview = JSON.stringify(body).slice(0, 300)
-      logger.debug(`[${tracker.requestId}] Incoming request body preview`, { preview })
-    } catch {}
-
-    const { toolName, payload } = ExecuteSchema.parse(body)
-
-    logger.info(`[${tracker.requestId}] Executing server tool`, { toolName })
-    const result = await routeExecution(toolName, payload, { userId })
-
-    try {
-      const resultPreview = JSON.stringify(result).slice(0, 300)
-      logger.debug(`[${tracker.requestId}] Server tool result preview`, { toolName, resultPreview })
-    } catch {}
-
-    return NextResponse.json({ success: true, result })
-  } catch (error) {
-    if (error instanceof z.ZodError) {
-      logger.debug(`[${tracker.requestId}] Zod validation error`, { issues: error.issues })
-      return createBadRequestResponse('Invalid request body for execute-copilot-server-tool')
-    }
-    logger.error(`[${tracker.requestId}] Failed to execute server tool:`, error)
-    const errorMessage = error instanceof Error ? error.message : 'Failed to execute server tool'
-    return createInternalServerErrorResponse(errorMessage)
-  }
-}
--- a/apps/sim/app/api/copilot/execute-tool/route.ts
+++ b/apps/sim/app/api/copilot/execute-tool/route.ts
@@ -1,247 +0,0 @@
-import { db } from '@sim/db'
-import { account, workflow } from '@sim/db/schema'
-import { createLogger } from '@sim/logger'
-import { and, eq } from 'drizzle-orm'
-import { type NextRequest, NextResponse } from 'next/server'
-import { z } from 'zod'
-import { getSession } from '@/lib/auth'
-import {
-  createBadRequestResponse,
-  createInternalServerErrorResponse,
-  createRequestTracker,
-  createUnauthorizedResponse,
-} from '@/lib/copilot/request-helpers'
-import { generateRequestId } from '@/lib/core/utils/request'
-import { getEffectiveDecryptedEnv } from '@/lib/environment/utils'
-import { refreshTokenIfNeeded } from '@/app/api/auth/oauth/utils'
-import { resolveEnvVarReferences } from '@/executor/utils/reference-validation'
-import { executeTool } from '@/tools'
-import { getTool, resolveToolId } from '@/tools/utils'
-
-const logger = createLogger('CopilotExecuteToolAPI')
-
-const ExecuteToolSchema = z.object({
-  toolCallId: z.string(),
-  toolName: z.string(),
-  arguments: z.record(z.any()).optional().default({}),
-  workflowId: z.string().optional(),
-})
-
-export async function POST(req: NextRequest) {
-  const tracker = createRequestTracker()
-
-  try {
-    const session = await getSession()
-    if (!session?.user?.id) {
-      return createUnauthorizedResponse()
-    }
-
-    const userId = session.user.id
-    const body = await req.json()
-
-    try {
-      const preview = JSON.stringify(body).slice(0, 300)
-      logger.debug(`[${tracker.requestId}] Incoming execute-tool request`, { preview })
-    } catch {}
-
-    const { toolCallId, toolName, arguments: toolArgs, workflowId } = ExecuteToolSchema.parse(body)
-
-    const resolvedToolName = resolveToolId(toolName)
-
-    logger.info(`[${tracker.requestId}] Executing tool`, {
-      toolCallId,
-      toolName,
-      resolvedToolName,
-      workflowId,
-      hasArgs: Object.keys(toolArgs).length > 0,
-    })
-
-    const toolConfig = getTool(resolvedToolName)
-    if (!toolConfig) {
-      // Find similar tool names to help debug
-      const { tools: allTools } = await import('@/tools/registry')
-      const allToolNames = Object.keys(allTools)
-      const prefix = toolName.split('_').slice(0, 2).join('_')
-      const similarTools = allToolNames
-        .filter((name) => name.startsWith(`${prefix.split('_')[0]}_`))
-        .slice(0, 10)
-
-      logger.warn(`[${tracker.requestId}] Tool not found in registry`, {
-        toolName,
-        prefix,
-        similarTools,
-        totalToolsInRegistry: allToolNames.length,
-      })
-      return NextResponse.json(
-        {
-          success: false,
-          error: `Tool not found: ${toolName}. Similar tools: ${similarTools.join(', ')}`,
-          toolCallId,
-        },
-        { status: 404 }
-      )
-    }
-
-    // Get the workspaceId from the workflow (env vars are stored at workspace level)
-    let workspaceId: string | undefined
-    if (workflowId) {
-      const workflowResult = await db
-        .select({ workspaceId: workflow.workspaceId })
-        .from(workflow)
-        .where(eq(workflow.id, workflowId))
-        .limit(1)
-      workspaceId = workflowResult[0]?.workspaceId ?? undefined
-    }
-
-    // Get decrypted environment variables early so we can resolve all {{VAR}} references
-    const decryptedEnvVars = await getEffectiveDecryptedEnv(userId, workspaceId)
-
-    logger.info(`[${tracker.requestId}] Fetched environment variables`, {
-      workflowId,
-      workspaceId,
-      envVarCount: Object.keys(decryptedEnvVars).length,
-      envVarKeys: Object.keys(decryptedEnvVars),
-    })
-
-    // Build execution params starting with LLM-provided arguments
-    // Resolve all {{ENV_VAR}} references in the arguments (deep for nested objects)
-    const executionParams: Record<string, any> = resolveEnvVarReferences(
-      toolArgs,
-      decryptedEnvVars,
-      { deep: true }
-    ) as Record<string, any>
-
-    logger.info(`[${tracker.requestId}] Resolved env var references in arguments`, {
-      toolName,
-      originalArgKeys: Object.keys(toolArgs),
-      resolvedArgKeys: Object.keys(executionParams),
-    })
-
-    // Resolve OAuth access token if required
-    if (toolConfig.oauth?.required && toolConfig.oauth.provider) {
-      const provider = toolConfig.oauth.provider
-      logger.info(`[${tracker.requestId}] Resolving OAuth token`, { provider })
-
-      try {
-        // Find the account for this provider and user
-        const accounts = await db
-          .select()
-          .from(account)
-          .where(and(eq(account.providerId, provider), eq(account.userId, userId)))
-          .limit(1)
-
-        if (accounts.length > 0) {
-          const acc = accounts[0]
-          const requestId = generateRequestId()
-          const { accessToken } = await refreshTokenIfNeeded(requestId, acc as any, acc.id)
-
-          if (accessToken) {
-            executionParams.accessToken = accessToken
-            logger.info(`[${tracker.requestId}] OAuth token resolved`, { provider })
-          } else {
-            logger.warn(`[${tracker.requestId}] No access token available`, { provider })
-            return NextResponse.json(
-              {
-                success: false,
-                error: `OAuth token not available for ${provider}. Please reconnect your account.`,
-                toolCallId,
-              },
-              { status: 400 }
-            )
-          }
-        } else {
-          logger.warn(`[${tracker.requestId}] No account found for provider`, { provider })
-          return NextResponse.json(
-            {
-              success: false,
-              error: `No ${provider} account connected. Please connect your account first.`,
-              toolCallId,
-            },
-            { status: 400 }
-          )
-        }
-      } catch (error) {
-        logger.error(`[${tracker.requestId}] Failed to resolve OAuth token`, {
-          provider,
-          error: error instanceof Error ? error.message : String(error),
-        })
-        return NextResponse.json(
-          {
-            success: false,
-            error: `Failed to get OAuth token for ${provider}`,
-            toolCallId,
-          },
-          { status: 500 }
-        )
-      }
-    }
-
-    // Check if tool requires an API key that wasn't resolved via {{ENV_VAR}} reference
-    const needsApiKey = toolConfig.params?.apiKey?.required
-
-    if (needsApiKey && !executionParams.apiKey) {
-      logger.warn(`[${tracker.requestId}] No API key found for tool`, { toolName })
-      return NextResponse.json(
-        {
-          success: false,
-          error: `API key not provided for ${toolName}. Use {{YOUR_API_KEY_ENV_VAR}} to reference your environment variable.`,
-          toolCallId,
-        },
-        { status: 400 }
-      )
-    }
-
-    // Add execution context
-    executionParams._context = {
-      workflowId,
-      userId,
-    }
-
-    // Special handling for function_execute - inject environment variables
-    if (toolName === 'function_execute') {
-      executionParams.envVars = decryptedEnvVars
-      executionParams.workflowVariables = {} // No workflow variables in copilot context
-      executionParams.blockData = {} // No block data in copilot context
-      executionParams.blockNameMapping = {} // No block mapping in copilot context
-      executionParams.language = executionParams.language || 'javascript'
-      executionParams.timeout = executionParams.timeout || 30000
-
-      logger.info(`[${tracker.requestId}] Injected env vars for function_execute`, {
-        envVarCount: Object.keys(decryptedEnvVars).length,
-      })
-    }
-
-    // Execute the tool
-    logger.info(`[${tracker.requestId}] Executing tool with resolved credentials`, {
-      toolName,
-      hasAccessToken: !!executionParams.accessToken,
-      hasApiKey: !!executionParams.apiKey,
-    })
-
-    const result = await executeTool(resolvedToolName, executionParams)
-
-    logger.info(`[${tracker.requestId}] Tool execution complete`, {
-      toolName,
-      success: result.success,
-      hasOutput: !!result.output,
-    })
-
-    return NextResponse.json({
-      success: true,
-      toolCallId,
-      result: {
-        success: result.success,
-        output: result.output,
-        error: result.error,
-      },
-    })
-  } catch (error) {
-    if (error instanceof z.ZodError) {
-      logger.debug(`[${tracker.requestId}] Zod validation error`, { issues: error.issues })
-      return createBadRequestResponse('Invalid request body for execute-tool')
-    }
-    logger.error(`[${tracker.requestId}] Failed to execute tool:`, error)
-    const errorMessage = error instanceof Error ? error.message : 'Failed to execute tool'
-    return createInternalServerErrorResponse(errorMessage)
-  }
-}
--- a/apps/sim/app/api/copilot/stats/route.test.ts
+++ b/apps/sim/app/api/copilot/stats/route.test.ts
@@ -40,6 +40,7 @@ describe('Copilot Stats API Route', () => {

    vi.doMock('@/lib/copilot/constants', () => ({
      SIM_AGENT_API_URL_DEFAULT: 'https://agent.sim.example.com',
+      SIM_AGENT_API_URL: 'https://agent.sim.example.com',
    }))

    vi.doMock('@/lib/core/config/env', async () => {
--- a/apps/sim/app/api/copilot/stats/route.ts
+++ b/apps/sim/app/api/copilot/stats/route.ts
@@ -1,6 +1,6 @@
 import { type NextRequest, NextResponse } from 'next/server'
 import { z } from 'zod'
-import { SIM_AGENT_API_URL_DEFAULT } from '@/lib/copilot/constants'
+import { SIM_AGENT_API_URL } from '@/lib/copilot/constants'
 import {
  authenticateCopilotRequestSessionOnly,
  createBadRequestResponse,
@@ -10,8 +10,6 @@ import {
 } from '@/lib/copilot/request-helpers'
 import { env } from '@/lib/core/config/env'

-const SIM_AGENT_API_URL = env.SIM_AGENT_API_URL || SIM_AGENT_API_URL_DEFAULT
-
 const BodySchema = z.object({
  messageId: z.string(),
  diffCreated: z.boolean(),
--- a/apps/sim/app/api/copilot/tools/mark-complete/route.ts
+++ b/apps/sim/app/api/copilot/tools/mark-complete/route.ts
@@ -1,123 +0,0 @@
-import { createLogger } from '@sim/logger'
-import { type NextRequest, NextResponse } from 'next/server'
-import { z } from 'zod'
-import { SIM_AGENT_API_URL_DEFAULT } from '@/lib/copilot/constants'
-import {
-  authenticateCopilotRequestSessionOnly,
-  createBadRequestResponse,
-  createInternalServerErrorResponse,
-  createRequestTracker,
-  createUnauthorizedResponse,
-} from '@/lib/copilot/request-helpers'
-import { env } from '@/lib/core/config/env'
-
-const logger = createLogger('CopilotMarkToolCompleteAPI')
-
-const SIM_AGENT_API_URL = env.SIM_AGENT_API_URL || SIM_AGENT_API_URL_DEFAULT
-
-const MarkCompleteSchema = z.object({
-  id: z.string(),
-  name: z.string(),
-  status: z.number().int(),
-  message: z.any().optional(),
-  data: z.any().optional(),
-})
-
-/**
- * POST /api/copilot/tools/mark-complete
- * Proxy to Sim Agent: POST /api/tools/mark-complete
- */
-export async function POST(req: NextRequest) {
-  const tracker = createRequestTracker()
-
-  try {
-    const { userId, isAuthenticated } = await authenticateCopilotRequestSessionOnly()
-    if (!isAuthenticated || !userId) {
-      return createUnauthorizedResponse()
-    }
-
-    const body = await req.json()
-
-    // Log raw body shape for diagnostics (avoid dumping huge payloads)
-    try {
-      const bodyPreview = JSON.stringify(body).slice(0, 300)
-      logger.debug(`[${tracker.requestId}] Incoming mark-complete raw body preview`, {
-        preview: `${bodyPreview}${bodyPreview.length === 300 ? '...' : ''}`,
-      })
-    } catch {}
-
-    const parsed = MarkCompleteSchema.parse(body)
-
-    const messagePreview = (() => {
-      try {
-        const s =
-          typeof parsed.message === 'string' ? parsed.message : JSON.stringify(parsed.message)
-        return s ? `${s.slice(0, 200)}${s.length > 200 ? '...' : ''}` : undefined
-      } catch {
-        return undefined
-      }
-    })()
-
-    logger.info(`[${tracker.requestId}] Forwarding tool mark-complete`, {
-      userId,
-      toolCallId: parsed.id,
-      toolName: parsed.name,
-      status: parsed.status,
-      hasMessage: parsed.message !== undefined,
-      hasData: parsed.data !== undefined,
-      messagePreview,
-      agentUrl: `${SIM_AGENT_API_URL}/api/tools/mark-complete`,
-    })
-
-    const agentRes = await fetch(`${SIM_AGENT_API_URL}/api/tools/mark-complete`, {
-      method: 'POST',
-      headers: {
-        'Content-Type': 'application/json',
-        ...(env.COPILOT_API_KEY ? { 'x-api-key': env.COPILOT_API_KEY } : {}),
-      },
-      body: JSON.stringify(parsed),
-    })
-
-    // Attempt to parse agent response JSON
-    let agentJson: any = null
-    let agentText: string | null = null
-    try {
-      agentJson = await agentRes.json()
-    } catch (_) {
-      try {
-        agentText = await agentRes.text()
-      } catch {}
-    }
-
-    logger.info(`[${tracker.requestId}] Agent responded to mark-complete`, {
-      status: agentRes.status,
-      ok: agentRes.ok,
-      responseJsonPreview: agentJson ? JSON.stringify(agentJson).slice(0, 300) : undefined,
-      responseTextPreview: agentText ? agentText.slice(0, 300) : undefined,
-    })
-
-    if (agentRes.ok) {
-      return NextResponse.json({ success: true })
-    }
-
-    const errorMessage =
-      agentJson?.error || agentText || `Agent responded with status ${agentRes.status}`
-    const status = agentRes.status >= 500 ? 500 : 400
-
-    logger.warn(`[${tracker.requestId}] Mark-complete failed`, {
-      status,
-      error: errorMessage,
-    })
-
-    return NextResponse.json({ success: false, error: errorMessage }, { status })
-  } catch (error) {
-    if (error instanceof z.ZodError) {
-      logger.warn(`[${tracker.requestId}] Invalid mark-complete request body`, {
-        issues: error.issues,
-      })
-      return createBadRequestResponse('Invalid request body for mark-complete')
-    }
-    logger.error(`[${tracker.requestId}] Failed to proxy mark-complete:`, error)
-    return createInternalServerErrorResponse('Failed to mark tool as complete')
-  }
-}
--- a/apps/sim/app/api/copilot/user-models/route.ts
+++ b/apps/sim/app/api/copilot/user-models/route.ts
@@ -28,6 +28,7 @@ const DEFAULT_ENABLED_MODELS: Record<CopilotModelId, boolean> = {
  'claude-4-sonnet': false,
  'claude-4.5-haiku': true,
  'claude-4.5-sonnet': true,
+  'claude-4.6-opus': true,
  'claude-4.5-opus': true,
  'claude-4.1-opus': false,
  'gemini-3-pro': true,
--- a/apps/sim/app/api/mcp/copilot/.well-known/oauth-authorization-server/route.ts
+++ b/apps/sim/app/api/mcp/copilot/.well-known/oauth-authorization-server/route.ts
@@ -0,0 +1,6 @@
+import type { NextRequest, NextResponse } from 'next/server'
+import { createMcpAuthorizationServerMetadataResponse } from '@/lib/mcp/oauth-discovery'
+
+export async function GET(request: NextRequest): Promise<NextResponse> {
+  return createMcpAuthorizationServerMetadataResponse(request)
+}
--- a/apps/sim/app/api/mcp/copilot/.well-known/oauth-protected-resource/route.ts
+++ b/apps/sim/app/api/mcp/copilot/.well-known/oauth-protected-resource/route.ts
@@ -0,0 +1,6 @@
+import type { NextRequest, NextResponse } from 'next/server'
+import { createMcpProtectedResourceMetadataResponse } from '@/lib/mcp/oauth-discovery'
+
+export async function GET(request: NextRequest): Promise<NextResponse> {
+  return createMcpProtectedResourceMetadataResponse(request)
+}
--- a/apps/sim/app/api/mcp/copilot/route.ts
+++ b/apps/sim/app/api/mcp/copilot/route.ts
@@ -0,0 +1,793 @@
+import { randomUUID } from 'node:crypto'
+import { Server } from '@modelcontextprotocol/sdk/server/index.js'
+import { StreamableHTTPServerTransport } from '@modelcontextprotocol/sdk/server/streamableHttp.js'
+import {
+  CallToolRequestSchema,
+  type CallToolResult,
+  ErrorCode,
+  type JSONRPCError,
+  ListToolsRequestSchema,
+  type ListToolsResult,
+  McpError,
+  type RequestId,
+} from '@modelcontextprotocol/sdk/types.js'
+import { db } from '@sim/db'
+import { userStats } from '@sim/db/schema'
+import { createLogger } from '@sim/logger'
+import { eq, sql } from 'drizzle-orm'
+import { type NextRequest, NextResponse } from 'next/server'
+import { getHighestPrioritySubscription } from '@/lib/billing/core/subscription'
+import { getCopilotModel } from '@/lib/copilot/config'
+import {
+  ORCHESTRATION_TIMEOUT_MS,
+  SIM_AGENT_API_URL,
+  SIM_AGENT_VERSION,
+} from '@/lib/copilot/constants'
+import { orchestrateCopilotStream } from '@/lib/copilot/orchestrator'
+import { orchestrateSubagentStream } from '@/lib/copilot/orchestrator/subagent'
+import {
+  executeToolServerSide,
+  prepareExecutionContext,
+} from '@/lib/copilot/orchestrator/tool-executor'
+import { DIRECT_TOOL_DEFS, SUBAGENT_TOOL_DEFS } from '@/lib/copilot/tools/mcp/definitions'
+import { env } from '@/lib/core/config/env'
+import { RateLimiter } from '@/lib/core/rate-limiter'
+import { resolveWorkflowIdForUser } from '@/lib/workflows/utils'
+
+const logger = createLogger('CopilotMcpAPI')
+const mcpRateLimiter = new RateLimiter()
+
+export const dynamic = 'force-dynamic'
+export const runtime = 'nodejs'
+export const maxDuration = 300
+
+interface CopilotKeyAuthResult {
+  success: boolean
+  userId?: string
+  error?: string
+}
+
+/**
+ * Validates a copilot API key by forwarding it to the Go copilot service's
+ * `/api/validate-key` endpoint. Returns the associated userId on success.
+ */
+async function authenticateCopilotApiKey(apiKey: string): Promise<CopilotKeyAuthResult> {
+  try {
+    const internalSecret = env.INTERNAL_API_SECRET
+    if (!internalSecret) {
+      logger.error('INTERNAL_API_SECRET not configured')
+      return { success: false, error: 'Server configuration error' }
+    }
+
+    const res = await fetch(`${SIM_AGENT_API_URL}/api/validate-key`, {
+      method: 'POST',
+      headers: {
+        'Content-Type': 'application/json',
+        'x-api-key': internalSecret,
+      },
+      body: JSON.stringify({ targetApiKey: apiKey }),
+      signal: AbortSignal.timeout(10_000),
+    })
+
+    if (!res.ok) {
+      const body = await res.json().catch(() => null)
+      const upstream = (body as Record<string, unknown>)?.message
+      const status = res.status
+
+      if (status === 401 || status === 403) {
+        return {
+          success: false,
+          error: `Invalid Copilot API key. Generate a new key in Settings → Copilot and set it in the x-api-key header.`,
+        }
+      }
+      if (status === 402) {
+        return {
+          success: false,
+          error: `Usage limit exceeded for this Copilot API key. Upgrade your plan or wait for your quota to reset.`,
+        }
+      }
+
+      return { success: false, error: String(upstream ?? 'Copilot API key validation failed') }
+    }
+
+    const data = (await res.json()) as { ok?: boolean; userId?: string }
+    if (!data.ok || !data.userId) {
+      return {
+        success: false,
+        error: 'Invalid Copilot API key. Generate a new key in Settings → Copilot.',
+      }
+    }
+
+    return { success: true, userId: data.userId }
+  } catch (error) {
+    logger.error('Copilot API key validation failed', { error })
+    return {
+      success: false,
+      error:
+        'Could not validate Copilot API key — the authentication service is temporarily unreachable. This is NOT a problem with the API key itself; please retry shortly.',
+    }
+  }
+}
+
+/**
+ * MCP Server instructions that guide LLMs on how to use the Sim copilot tools.
+ * This is included in the initialize response to help external LLMs understand
+ * the workflow lifecycle and best practices.
+ */
+const MCP_SERVER_INSTRUCTIONS = `
+## Sim Workflow Copilot
+
+Sim is a workflow automation platform. Workflows are visual pipelines of connected blocks (Agent, Function, Condition, API, integrations, etc.). The Agent block is the core — an LLM with tools, memory, structured output, and knowledge bases.
+
+### Workflow Lifecycle (Happy Path)
+
+1. \`list_workspaces\` → know where to work
+2. \`create_workflow(name, workspaceId)\` → get a workflowId
+3. \`sim_build(request, workflowId)\` → plan and build in one pass
+4. \`sim_test(request, workflowId)\` → verify it works
+5. \`sim_deploy("deploy as api", workflowId)\` → make it accessible externally (optional)
+
+For fine-grained control, use \`sim_plan\` → \`sim_edit\` instead of \`sim_build\`. Pass the plan object from sim_plan EXACTLY as-is to sim_edit's context.plan field.
+
+### Working with Existing Workflows
+
+When the user refers to a workflow by name or description ("the email one", "my Slack bot"):
+1. Use \`sim_discovery\` to find it by functionality
+2. Or use \`list_workflows\` and match by name
+3. Then pass the workflowId to other tools
+
+### Organization
+
+- \`rename_workflow\` — rename a workflow
+- \`move_workflow\` — move a workflow into a folder (or root with null)
+- \`move_folder\` — nest a folder inside another (or root with null)
+- \`create_folder(name, parentId)\` — create nested folder hierarchies
+
+### Key Rules
+
+- You can test workflows immediately after building — deployment is only needed for external access (API, chat, MCP).
+- All copilot tools (build, plan, edit, deploy, test, debug) require workflowId.
+- If the user reports errors → use \`sim_debug\` first, don't guess.
+- Variable syntax: \`<blockname.field>\` for block outputs, \`{{ENV_VAR}}\` for env vars.
+`
+
+type HeaderMap = Record<string, string | string[] | undefined>
+
+function createError(id: RequestId, code: ErrorCode | number, message: string): JSONRPCError {
+  return {
+    jsonrpc: '2.0',
+    id,
+    error: { code, message },
+  }
+}
+
+function normalizeRequestHeaders(request: NextRequest): HeaderMap {
+  const headers: HeaderMap = {}
+
+  request.headers.forEach((value, key) => {
+    headers[key.toLowerCase()] = value
+  })
+
+  return headers
+}
+
+function readHeader(headers: HeaderMap | undefined, name: string): string | undefined {
+  if (!headers) return undefined
+  const value = headers[name.toLowerCase()]
+  if (Array.isArray(value)) {
+    return value[0]
+  }
+  return value
+}
+
+class NextResponseCapture {
+  private _status = 200
+  private _headers = new Headers()
+  private _controller: ReadableStreamDefaultController<Uint8Array> | null = null
+  private _pendingChunks: Uint8Array[] = []
+  private _closeHandlers: Array<() => void> = []
+  private _errorHandlers: Array<(error: Error) => void> = []
+  private _headersWritten = false
+  private _ended = false
+  private _headersPromise: Promise<void>
+  private _resolveHeaders: (() => void) | null = null
+  private _endedPromise: Promise<void>
+  private _resolveEnded: (() => void) | null = null
+  readonly readable: ReadableStream<Uint8Array>
+
+  constructor() {
+    this._headersPromise = new Promise<void>((resolve) => {
+      this._resolveHeaders = resolve
+    })
+
+    this._endedPromise = new Promise<void>((resolve) => {
+      this._resolveEnded = resolve
+    })
+
+    this.readable = new ReadableStream<Uint8Array>({
+      start: (controller) => {
+        this._controller = controller
+        if (this._pendingChunks.length > 0) {
+          for (const chunk of this._pendingChunks) {
+            controller.enqueue(chunk)
+          }
+          this._pendingChunks = []
+        }
+      },
+      cancel: () => {
+        this._ended = true
+        this._resolveEnded?.()
+        this.triggerCloseHandlers()
+      },
+    })
+  }
+
+  private markHeadersWritten(): void {
+    if (this._headersWritten) return
+    this._headersWritten = true
+    this._resolveHeaders?.()
+  }
+
+  private triggerCloseHandlers(): void {
+    for (const handler of this._closeHandlers) {
+      try {
+        handler()
+      } catch (error) {
+        this.triggerErrorHandlers(error instanceof Error ? error : new Error(String(error)))
+      }
+    }
+  }
+
+  private triggerErrorHandlers(error: Error): void {
+    for (const errorHandler of this._errorHandlers) {
+      errorHandler(error)
+    }
+  }
+
+  private normalizeChunk(chunk: unknown): Uint8Array | null {
+    if (typeof chunk === 'string') {
+      return new TextEncoder().encode(chunk)
+    }
+
+    if (chunk instanceof Uint8Array) {
+      return chunk
+    }
+
+    if (chunk === undefined || chunk === null) {
+      return null
+    }
+
+    return new TextEncoder().encode(String(chunk))
+  }
+
+  writeHead(status: number, headers?: Record<string, string | number | string[]>): this {
+    this._status = status
+
+    if (headers) {
+      Object.entries(headers).forEach(([key, value]) => {
+        if (Array.isArray(value)) {
+          this._headers.set(key, value.join(', '))
+        } else {
+          this._headers.set(key, String(value))
+        }
+      })
+    }
+
+    this.markHeadersWritten()
+    return this
+  }
+
+  flushHeaders(): this {
+    this.markHeadersWritten()
+    return this
+  }
+
+  write(chunk: unknown): boolean {
+    const normalized = this.normalizeChunk(chunk)
+    if (!normalized) return true
+
+    this.markHeadersWritten()
+
+    if (this._controller) {
+      try {
+        this._controller.enqueue(normalized)
+      } catch (error) {
+        this.triggerErrorHandlers(error instanceof Error ? error : new Error(String(error)))
+      }
+    } else {
+      this._pendingChunks.push(normalized)
+    }
+
+    return true
+  }
+
+  end(chunk?: unknown): this {
+    if (chunk !== undefined) this.write(chunk)
+    this.markHeadersWritten()
+    if (this._ended) return this
+
+    this._ended = true
+    this._resolveEnded?.()
+
+    if (this._controller) {
+      try {
+        this._controller.close()
+      } catch (error) {
+        this.triggerErrorHandlers(error instanceof Error ? error : new Error(String(error)))
+      }
+    }
+
+    this.triggerCloseHandlers()
+
+    return this
+  }
+
+  async waitForHeaders(timeoutMs = 30000): Promise<void> {
+    if (this._headersWritten) return
+
+    await Promise.race([
+      this._headersPromise,
+      new Promise<void>((resolve) => {
+        setTimeout(resolve, timeoutMs)
+      }),
+    ])
+  }
+
+  async waitForEnd(timeoutMs = 30000): Promise<void> {
+    if (this._ended) return
+
+    await Promise.race([
+      this._endedPromise,
+      new Promise<void>((resolve) => {
+        setTimeout(resolve, timeoutMs)
+      }),
+    ])
+  }
+
+  on(event: 'close' | 'error', handler: (() => void) | ((error: Error) => void)): this {
+    if (event === 'close') {
+      this._closeHandlers.push(handler as () => void)
+    }
+
+    if (event === 'error') {
+      this._errorHandlers.push(handler as (error: Error) => void)
+    }
+
+    return this
+  }
+
+  toNextResponse(): NextResponse {
+    return new NextResponse(this.readable, {
+      status: this._status,
+      headers: this._headers,
+    })
+  }
+}
+
+function buildMcpServer(abortSignal?: AbortSignal): Server {
+  const server = new Server(
+    {
+      name: 'sim-copilot',
+      version: '1.0.0',
+    },
+    {
+      capabilities: { tools: {} },
+      instructions: MCP_SERVER_INSTRUCTIONS,
+    }
+  )
+
+  server.setRequestHandler(ListToolsRequestSchema, async () => {
+    const directTools = DIRECT_TOOL_DEFS.map((tool) => ({
+      name: tool.name,
+      description: tool.description,
+      inputSchema: tool.inputSchema,
+    }))
+
+    const subagentTools = SUBAGENT_TOOL_DEFS.map((tool) => ({
+      name: tool.name,
+      description: tool.description,
+      inputSchema: tool.inputSchema,
+    }))
+
+    const result: ListToolsResult = {
+      tools: [...directTools, ...subagentTools],
+    }
+
+    return result
+  })
+
+  server.setRequestHandler(CallToolRequestSchema, async (request, extra) => {
+    const headers = (extra.requestInfo?.headers || {}) as HeaderMap
+    const apiKeyHeader = readHeader(headers, 'x-api-key')
+
+    if (!apiKeyHeader) {
+      return {
+        content: [
+          {
+            type: 'text' as const,
+            text: 'AUTHENTICATION ERROR: No Copilot API key provided. The user must set their Copilot API key in the x-api-key header. They can generate one in the Sim app under Settings → Copilot. Do NOT retry — this will fail until the key is configured.',
+          },
+        ],
+        isError: true,
+      }
+    }
+
+    const authResult = await authenticateCopilotApiKey(apiKeyHeader)
+    if (!authResult.success || !authResult.userId) {
+      logger.warn('MCP copilot key auth failed', { method: request.method })
+      return {
+        content: [
+          {
+            type: 'text' as const,
+            text: `AUTHENTICATION ERROR: ${authResult.error} Do NOT retry — this will fail until the user fixes their Copilot API key.`,
+          },
+        ],
+        isError: true,
+      }
+    }
+
+    const rateLimitResult = await mcpRateLimiter.checkRateLimitWithSubscription(
+      authResult.userId,
+      await getHighestPrioritySubscription(authResult.userId),
+      'api-endpoint',
+      false
+    )
+
+    if (!rateLimitResult.allowed) {
+      return {
+        content: [
+          {
+            type: 'text' as const,
+            text: `RATE LIMIT: Too many requests. Please wait and retry after ${rateLimitResult.resetAt.toISOString()}.`,
+          },
+        ],
+        isError: true,
+      }
+    }
+
+    const params = request.params as
+      | { name?: string; arguments?: Record<string, unknown> }
+      | undefined
+    if (!params?.name) {
+      throw new McpError(ErrorCode.InvalidParams, 'Tool name required')
+    }
+
+    const result = await handleToolsCall(
+      {
+        name: params.name,
+        arguments: params.arguments,
+      },
+      authResult.userId,
+      abortSignal
+    )
+
+    trackMcpCopilotCall(authResult.userId)
+
+    return result
+  })
+
+  return server
+}
+
+async function handleMcpRequestWithSdk(
+  request: NextRequest,
+  parsedBody: unknown
+): Promise<NextResponse> {
+  const server = buildMcpServer(request.signal)
+  const transport = new StreamableHTTPServerTransport({
+    sessionIdGenerator: undefined,
+    enableJsonResponse: true,
+  })
+
+  const responseCapture = new NextResponseCapture()
+  const requestAdapter = {
+    method: request.method,
+    headers: normalizeRequestHeaders(request),
+  }
+
+  await server.connect(transport)
+
+  try {
+    await transport.handleRequest(requestAdapter as any, responseCapture as any, parsedBody)
+    await responseCapture.waitForHeaders()
+    // Must exceed the longest possible tool execution (build = 5 min).
+    // Using ORCHESTRATION_TIMEOUT_MS + 60 s buffer so the orchestrator can
+    // finish or time-out on its own before the transport is torn down.
+    await responseCapture.waitForEnd(ORCHESTRATION_TIMEOUT_MS + 60_000)
+    return responseCapture.toNextResponse()
+  } finally {
+    await server.close().catch(() => {})
+    await transport.close().catch(() => {})
+  }
+}
+
+export async function GET() {
+  // Return 405 to signal that server-initiated SSE notifications are not
+  // supported.  Without this, clients like mcp-remote will repeatedly
+  // reconnect trying to open an SSE stream, flooding the logs with GETs.
+  return new NextResponse(null, { status: 405 })
+}
+
+export async function POST(request: NextRequest) {
+  try {
+    let parsedBody: unknown
+
+    try {
+      parsedBody = await request.json()
+    } catch {
+      return NextResponse.json(createError(0, ErrorCode.ParseError, 'Invalid JSON body'), {
+        status: 400,
+      })
+    }
+
+    return await handleMcpRequestWithSdk(request, parsedBody)
+  } catch (error) {
+    logger.error('Error handling MCP request', { error })
+    return NextResponse.json(createError(0, ErrorCode.InternalError, 'Internal error'), {
+      status: 500,
+    })
+  }
+}
+
+export async function DELETE(request: NextRequest) {
+  void request
+  return NextResponse.json(createError(0, -32000, 'Method not allowed.'), { status: 405 })
+}
+
+/**
+ * Increment MCP copilot call counter in userStats (fire-and-forget).
+ */
+function trackMcpCopilotCall(userId: string): void {
+  db.update(userStats)
+    .set({
+      totalMcpCopilotCalls: sql`total_mcp_copilot_calls + 1`,
+      lastActive: new Date(),
+    })
+    .where(eq(userStats.userId, userId))
+    .then(() => {})
+    .catch((error) => {
+      logger.error('Failed to track MCP copilot call', { error, userId })
+    })
+}
+
+async function handleToolsCall(
+  params: { name: string; arguments?: Record<string, unknown> },
+  userId: string,
+  abortSignal?: AbortSignal
+): Promise<CallToolResult> {
+  const args = params.arguments || {}
+
+  const directTool = DIRECT_TOOL_DEFS.find((tool) => tool.name === params.name)
+  if (directTool) {
+    return handleDirectToolCall(directTool, args, userId)
+  }
+
+  const subagentTool = SUBAGENT_TOOL_DEFS.find((tool) => tool.name === params.name)
+  if (subagentTool) {
+    return handleSubagentToolCall(subagentTool, args, userId, abortSignal)
+  }
+
+  throw new McpError(ErrorCode.MethodNotFound, `Tool not found: ${params.name}`)
+}
+
+async function handleDirectToolCall(
+  toolDef: (typeof DIRECT_TOOL_DEFS)[number],
+  args: Record<string, unknown>,
+  userId: string
+): Promise<CallToolResult> {
+  try {
+    const execContext = await prepareExecutionContext(userId, (args.workflowId as string) || '')
+
+    const toolCall = {
+      id: randomUUID(),
+      name: toolDef.toolId,
+      status: 'pending' as const,
+      params: args as Record<string, any>,
+      startTime: Date.now(),
+    }
+
+    const result = await executeToolServerSide(toolCall, execContext)
+
+    return {
+      content: [
+        {
+          type: 'text',
+          text: JSON.stringify(result.output ?? result, null, 2),
+        },
+      ],
+      isError: !result.success,
+    }
+  } catch (error) {
+    logger.error('Direct tool execution failed', { tool: toolDef.name, error })
+    return {
+      content: [
+        {
+          type: 'text',
+          text: `Tool execution failed: ${error instanceof Error ? error.message : String(error)}`,
+        },
+      ],
+      isError: true,
+    }
+  }
+}
+
+/**
+ * Build mode uses the main chat orchestrator with the 'fast' command instead of
+ * the subagent endpoint. In Go, 'build' is not a registered subagent — it's a mode
+ * (ModeFast) on the main chat processor that bypasses subagent orchestration and
+ * executes all tools directly.
+ */
+async function handleBuildToolCall(
+  args: Record<string, unknown>,
+  userId: string,
+  abortSignal?: AbortSignal
+): Promise<CallToolResult> {
+  try {
+    const requestText = (args.request as string) || JSON.stringify(args)
+    const { model } = getCopilotModel('chat')
+    const workflowId = args.workflowId as string | undefined
+
+    const resolved = workflowId ? { workflowId } : await resolveWorkflowIdForUser(userId)
+
+    if (!resolved?.workflowId) {
+      return {
+        content: [
+          {
+            type: 'text',
+            text: JSON.stringify(
+              {
+                success: false,
+                error: 'workflowId is required for build. Call create_workflow first.',
+              },
+              null,
+              2
+            ),
+          },
+        ],
+        isError: true,
+      }
+    }
+
+    const chatId = randomUUID()
+
+    const requestPayload = {
+      message: requestText,
+      workflowId: resolved.workflowId,
+      userId,
+      model,
+      mode: 'agent',
+      commands: ['fast'],
+      messageId: randomUUID(),
+      version: SIM_AGENT_VERSION,
+      headless: true,
+      chatId,
+      source: 'mcp',
+    }
+
+    const result = await orchestrateCopilotStream(requestPayload, {
+      userId,
+      workflowId: resolved.workflowId,
+      chatId,
+      autoExecuteTools: true,
+      timeout: 300000,
+      interactive: false,
+      abortSignal,
+    })
+
+    const responseData = {
+      success: result.success,
+      content: result.content,
+      toolCalls: result.toolCalls,
+      error: result.error,
+    }
+
+    return {
+      content: [{ type: 'text', text: JSON.stringify(responseData, null, 2) }],
+      isError: !result.success,
+    }
+  } catch (error) {
+    logger.error('Build tool call failed', { error })
+    return {
+      content: [
+        {
+          type: 'text',
+          text: `Build failed: ${error instanceof Error ? error.message : String(error)}`,
+        },
+      ],
+      isError: true,
+    }
+  }
+}
+
+async function handleSubagentToolCall(
+  toolDef: (typeof SUBAGENT_TOOL_DEFS)[number],
+  args: Record<string, unknown>,
+  userId: string,
+  abortSignal?: AbortSignal
+): Promise<CallToolResult> {
+  if (toolDef.agentId === 'build') {
+    return handleBuildToolCall(args, userId, abortSignal)
+  }
+
+  try {
+    const requestText =
+      (args.request as string) ||
+      (args.message as string) ||
+      (args.error as string) ||
+      JSON.stringify(args)
+
+    const context = (args.context as Record<string, unknown>) || {}
+    if (args.plan && !context.plan) {
+      context.plan = args.plan
+    }
+
+    const { model } = getCopilotModel('chat')
+
+    const result = await orchestrateSubagentStream(
+      toolDef.agentId,
+      {
+        message: requestText,
+        workflowId: args.workflowId,
+        workspaceId: args.workspaceId,
+        context,
+        model,
+        headless: true,
+        source: 'mcp',
+      },
+      {
+        userId,
+        workflowId: args.workflowId as string | undefined,
+        workspaceId: args.workspaceId as string | undefined,
+        abortSignal,
+      }
+    )
+
+    let responseData: unknown
+
+    if (result.structuredResult) {
+      responseData = {
+        success: result.structuredResult.success ?? result.success,
+        type: result.structuredResult.type,
+        summary: result.structuredResult.summary,
+        data: result.structuredResult.data,
+      }
+    } else if (result.error) {
+      responseData = {
+        success: false,
+        error: result.error,
+        errors: result.errors,
+      }
+    } else {
+      responseData = {
+        success: result.success,
+        content: result.content,
+      }
+    }
+
+    return {
+      content: [
+        {
+          type: 'text',
+          text: JSON.stringify(responseData, null, 2),
+        },
+      ],
+      isError: !result.success,
+    }
+  } catch (error) {
+    logger.error('Subagent tool call failed', {
+      tool: toolDef.name,
+      agentId: toolDef.agentId,
+      error,
+    })
+
+    return {
+      content: [
+        {
+          type: 'text',
+          text: `Subagent call failed: ${error instanceof Error ? error.message : String(error)}`,
+        },
+      ],
+      isError: true,
+    }
+  }
+}
--- a/apps/sim/app/api/v1/copilot/chat/route.ts
+++ b/apps/sim/app/api/v1/copilot/chat/route.ts
@@ -0,0 +1,114 @@
+import { createLogger } from '@sim/logger'
+import { type NextRequest, NextResponse } from 'next/server'
+import { z } from 'zod'
+import { getCopilotModel } from '@/lib/copilot/config'
+import { SIM_AGENT_VERSION } from '@/lib/copilot/constants'
+import { COPILOT_REQUEST_MODES } from '@/lib/copilot/models'
+import { orchestrateCopilotStream } from '@/lib/copilot/orchestrator'
+import { resolveWorkflowIdForUser } from '@/lib/workflows/utils'
+import { authenticateV1Request } from '@/app/api/v1/auth'
+
+const logger = createLogger('CopilotHeadlessAPI')
+
+const RequestSchema = z.object({
+  message: z.string().min(1, 'message is required'),
+  workflowId: z.string().optional(),
+  workflowName: z.string().optional(),
+  chatId: z.string().optional(),
+  mode: z.enum(COPILOT_REQUEST_MODES).optional().default('agent'),
+  model: z.string().optional(),
+  autoExecuteTools: z.boolean().optional().default(true),
+  timeout: z.number().optional().default(300000),
+})
+
+/**
+ * POST /api/v1/copilot/chat
+ * Headless copilot endpoint for server-side orchestration.
+ *
+ * workflowId is optional - if not provided:
+ * - If workflowName is provided, finds that workflow
+ * - Otherwise uses the user's first workflow as context
+ * - The copilot can still operate on any workflow using list_user_workflows
+ */
+export async function POST(req: NextRequest) {
+  const auth = await authenticateV1Request(req)
+  if (!auth.authenticated || !auth.userId) {
+    return NextResponse.json(
+      { success: false, error: auth.error || 'Unauthorized' },
+      { status: 401 }
+    )
+  }
+
+  try {
+    const body = await req.json()
+    const parsed = RequestSchema.parse(body)
+    const defaults = getCopilotModel('chat')
+    const selectedModel = parsed.model || defaults.model
+
+    // Resolve workflow ID
+    const resolved = await resolveWorkflowIdForUser(
+      auth.userId,
+      parsed.workflowId,
+      parsed.workflowName
+    )
+    if (!resolved) {
+      return NextResponse.json(
+        {
+          success: false,
+          error: 'No workflows found. Create a workflow first or provide a valid workflowId.',
+        },
+        { status: 400 }
+      )
+    }
+
+    // Transform mode to transport mode (same as client API)
+    // build and agent both map to 'agent' on the backend
+    const effectiveMode = parsed.mode === 'agent' ? 'build' : parsed.mode
+    const transportMode = effectiveMode === 'build' ? 'agent' : effectiveMode
+
+    // Always generate a chatId - required for artifacts system to work with subagents
+    const chatId = parsed.chatId || crypto.randomUUID()
+
+    const requestPayload = {
+      message: parsed.message,
+      workflowId: resolved.workflowId,
+      userId: auth.userId,
+      model: selectedModel,
+      mode: transportMode,
+      messageId: crypto.randomUUID(),
+      version: SIM_AGENT_VERSION,
+      headless: true,
+      chatId,
+    }
+
+    const result = await orchestrateCopilotStream(requestPayload, {
+      userId: auth.userId,
+      workflowId: resolved.workflowId,
+      chatId,
+      autoExecuteTools: parsed.autoExecuteTools,
+      timeout: parsed.timeout,
+      interactive: false,
+    })
+
+    return NextResponse.json({
+      success: result.success,
+      content: result.content,
+      toolCalls: result.toolCalls,
+      chatId: result.chatId || chatId, // Return the chatId for conversation continuity
+      conversationId: result.conversationId,
+      error: result.error,
+    })
+  } catch (error) {
+    if (error instanceof z.ZodError) {
+      return NextResponse.json(
+        { success: false, error: 'Invalid request', details: error.errors },
+        { status: 400 }
+      )
+    }
+
+    logger.error('Headless copilot request failed', {
+      error: error instanceof Error ? error.message : String(error),
+    })
+    return NextResponse.json({ success: false, error: 'Internal server error' }, { status: 500 })
+  }
+}
--- a/apps/sim/app/api/workflows/[id]/execute/route.ts
+++ b/apps/sim/app/api/workflows/[id]/execute/route.ts
@@ -33,7 +33,11 @@ import { createHttpResponseFromBlock, workflowHasResponseBlock } from '@/lib/wor
 import { executeWorkflowJob, type WorkflowExecutionPayload } from '@/background/workflow-execution'
 import { normalizeName } from '@/executor/constants'
 import { ExecutionSnapshot } from '@/executor/execution/snapshot'
-import type { ExecutionMetadata, IterationContext } from '@/executor/execution/types'
+import type {
+  ExecutionMetadata,
+  IterationContext,
+  SerializableExecutionState,
+} from '@/executor/execution/types'
 import type { NormalizedBlockOutput, StreamingExecution } from '@/executor/types'
 import { hasExecutionResult } from '@/executor/utils/errors'
 import { Serializer } from '@/serializer'
@@ -62,20 +66,23 @@ const ExecuteWorkflowSchema = z.object({
  runFromBlock: z
    .object({
      startBlockId: z.string().min(1, 'Start block ID is required'),
-      sourceSnapshot: z.object({
-        blockStates: z.record(z.any()),
-        executedBlocks: z.array(z.string()),
-        blockLogs: z.array(z.any()),
-        decisions: z.object({
-          router: z.record(z.string()),
-          condition: z.record(z.string()),
-        }),
-        completedLoops: z.array(z.string()),
-        loopExecutions: z.record(z.any()).optional(),
-        parallelExecutions: z.record(z.any()).optional(),
-        parallelBlockMapping: z.record(z.any()).optional(),
-        activeExecutionPath: z.array(z.string()),
-      }),
+      sourceSnapshot: z
+        .object({
+          blockStates: z.record(z.any()),
+          executedBlocks: z.array(z.string()),
+          blockLogs: z.array(z.any()),
+          decisions: z.object({
+            router: z.record(z.string()),
+            condition: z.record(z.string()),
+          }),
+          completedLoops: z.array(z.string()),
+          loopExecutions: z.record(z.any()).optional(),
+          parallelExecutions: z.record(z.any()).optional(),
+          parallelBlockMapping: z.record(z.any()).optional(),
+          activeExecutionPath: z.array(z.string()),
+        })
+        .optional(),
+      executionId: z.string().optional(),
    })
    .optional(),
 })
@@ -269,9 +276,47 @@ export async function POST(req: NextRequest, { params }: { params: Promise<{ id:
      base64MaxBytes,
      workflowStateOverride,
      stopAfterBlockId,
-      runFromBlock,
+      runFromBlock: rawRunFromBlock,
    } = validation.data

+    // Resolve runFromBlock snapshot from executionId if needed
+    let resolvedRunFromBlock:
+      | { startBlockId: string; sourceSnapshot: SerializableExecutionState }
+      | undefined
+    if (rawRunFromBlock) {
+      if (rawRunFromBlock.sourceSnapshot) {
+        resolvedRunFromBlock = {
+          startBlockId: rawRunFromBlock.startBlockId,
+          sourceSnapshot: rawRunFromBlock.sourceSnapshot as SerializableExecutionState,
+        }
+      } else if (rawRunFromBlock.executionId) {
+        const { getExecutionState, getLatestExecutionState } = await import(
+          '@/lib/workflows/executor/execution-state'
+        )
+        const snapshot =
+          rawRunFromBlock.executionId === 'latest'
+            ? await getLatestExecutionState(workflowId)
+            : await getExecutionState(rawRunFromBlock.executionId)
+        if (!snapshot) {
+          return NextResponse.json(
+            {
+              error: `No execution state found for ${rawRunFromBlock.executionId === 'latest' ? 'workflow' : `execution ${rawRunFromBlock.executionId}`}. Run the full workflow first.`,
+            },
+            { status: 400 }
+          )
+        }
+        resolvedRunFromBlock = {
+          startBlockId: rawRunFromBlock.startBlockId,
+          sourceSnapshot: snapshot,
+        }
+      } else {
+        return NextResponse.json(
+          { error: 'runFromBlock requires either sourceSnapshot or executionId' },
+          { status: 400 }
+        )
+      }
+    }
+
    // For API key and internal JWT auth, the entire body is the input (except for our control fields)
    // For session auth, the input is explicitly provided in the input field
    const input =
@@ -496,7 +541,7 @@ export async function POST(req: NextRequest, { params }: { params: Promise<{ id:
          includeFileBase64,
          base64MaxBytes,
          stopAfterBlockId,
-          runFromBlock,
+          runFromBlock: resolvedRunFromBlock,
          abortSignal: timeoutController.signal,
        })

@@ -837,7 +882,7 @@ export async function POST(req: NextRequest, { params }: { params: Promise<{ id:
            includeFileBase64,
            base64MaxBytes,
            stopAfterBlockId,
-            runFromBlock,
+            runFromBlock: resolvedRunFromBlock,
          })

          if (result.status === 'paused') {