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
2026-02-12 23:45:07 -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/.well-known/oauth-authorization-server/[...issuer]/route.ts
+++ b/apps/sim/app/.well-known/oauth-authorization-server/[...issuer]/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/.well-known/oauth-authorization-server/api/mcp/copilot/route.ts
+++ b/apps/sim/app/.well-known/oauth-authorization-server/api/mcp/copilot/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/.well-known/oauth-authorization-server/route.ts
+++ b/apps/sim/app/.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/.well-known/oauth-protected-resource/api/mcp/copilot/route.ts
+++ b/apps/sim/app/.well-known/oauth-protected-resource/api/mcp/copilot/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/.well-known/oauth-protected-resource/route.ts
+++ b/apps/sim/app/.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/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') {
--- a/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/copilot/components/copilot-message/copilot-message.tsx
+++ b/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/copilot/components/copilot-message/copilot-message.tsx
@@ -211,7 +211,7 @@ const CopilotMessage: FC<CopilotMessageProps> = memo(
        if (block.type === 'text') {
          const isLastTextBlock =
            index === message.contentBlocks!.length - 1 && block.type === 'text'
-          const parsed = parseSpecialTags(block.content)
+          const parsed = parseSpecialTags(block.content ?? '')
          // Mask credential IDs in the displayed content
          const cleanBlockContent = maskCredentialValue(
            parsed.cleanContent.replace(/\n{3,}/g, '\n\n')
@@ -243,7 +243,7 @@ const CopilotMessage: FC<CopilotMessageProps> = memo(
          return (
            <div key={blockKey} className='w-full'>
              <ThinkingBlock
-                content={maskCredentialValue(block.content)}
+                content={maskCredentialValue(block.content ?? '')}
                isStreaming={isActivelyStreaming}
                hasFollowingContent={hasFollowingContent}
                hasSpecialTags={hasSpecialTags}
@@ -251,7 +251,7 @@ const CopilotMessage: FC<CopilotMessageProps> = memo(
            </div>
          )
        }
-        if (block.type === 'tool_call') {
+        if (block.type === 'tool_call' && block.toolCall) {
          const blockKey = `tool-${block.toolCall.id}`

          return (
--- a/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/copilot/components/tool-call/tool-call.tsx
+++ b/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/copilot/components/tool-call/tool-call.tsx
@@ -1,20 +1,19 @@
 'use client'

 import { memo, useEffect, useMemo, useRef, useState } from 'react'
+import { createLogger } from '@sim/logger'
 import clsx from 'clsx'
 import { ChevronUp, LayoutList } from 'lucide-react'
 import Editor from 'react-simple-code-editor'
 import { Button, Code, getCodeEditorProps, highlight, languages } from '@/components/emcn'
-import { ClientToolCallState } from '@/lib/copilot/tools/client/base-tool'
-import { getClientTool } from '@/lib/copilot/tools/client/manager'
-import { getRegisteredTools } from '@/lib/copilot/tools/client/registry'
-import '@/lib/copilot/tools/client/init-tool-configs'
 import {
-  getSubagentLabels as getSubagentLabelsFromConfig,
-  getToolUIConfig,
-  hasInterrupt as hasInterruptFromConfig,
-  isSpecialTool as isSpecialToolFromConfig,
-} from '@/lib/copilot/tools/client/ui-config'
+  CLIENT_EXECUTABLE_RUN_TOOLS,
+  executeRunToolOnClient,
+} from '@/lib/copilot/client-sse/run-tool-execution'
+import {
+  ClientToolCallState,
+  TOOL_DISPLAY_REGISTRY,
+} from '@/lib/copilot/tools/client/tool-display-registry'
 import { formatDuration } from '@/lib/core/utils/formatting'
 import { CopilotMarkdownRenderer } from '@/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/copilot/components/copilot-message/components/markdown-renderer'
 import { SmoothStreamingText } from '@/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/copilot/components/copilot-message/components/smooth-streaming'
@@ -25,7 +24,6 @@ import { getDisplayValue } from '@/app/workspace/[workspaceId]/w/[workflowId]/co
 import { getBlock } from '@/blocks/registry'
 import type { CopilotToolCall } from '@/stores/panel'
 import { useCopilotStore } from '@/stores/panel'
-import { CLASS_TOOL_METADATA } from '@/stores/panel/copilot/store'
 import type { SubAgentContentBlock } from '@/stores/panel/copilot/types'
 import { useWorkflowStore } from '@/stores/workflows/workflow/store'

@@ -710,8 +708,8 @@ const ShimmerOverlayText = memo(function ShimmerOverlayText({
 * @returns The completion label from UI config, defaults to 'Thought'
 */
 function getSubagentCompletionLabel(toolName: string): string {
-  const labels = getSubagentLabelsFromConfig(toolName, false)
-  return labels?.completed ?? 'Thought'
+  const labels = TOOL_DISPLAY_REGISTRY[toolName]?.uiConfig?.subagentLabels
+  return labels?.completed || 'Thought'
 }

 /**
@@ -943,7 +941,7 @@ const SubagentContentRenderer = memo(function SubagentContentRenderer({
 * Determines if a tool call should display with special gradient styling.
 */
 function isSpecialToolCall(toolCall: CopilotToolCall): boolean {
-  return isSpecialToolFromConfig(toolCall.name)
+  return TOOL_DISPLAY_REGISTRY[toolCall.name]?.uiConfig?.isSpecial === true
 }

 /**
@@ -1223,143 +1221,88 @@ const WorkflowEditSummary = memo(function WorkflowEditSummary({

 /** Checks if a tool is server-side executed (not a client tool) */
 function isIntegrationTool(toolName: string): boolean {
-  return !CLASS_TOOL_METADATA[toolName]
+  return !TOOL_DISPLAY_REGISTRY[toolName]
 }

 function shouldShowRunSkipButtons(toolCall: CopilotToolCall): boolean {
-  if (hasInterruptFromConfig(toolCall.name) && toolCall.state === 'pending') {
+  if (!toolCall.name || toolCall.name === 'unknown_tool') {
+    return false
+  }
+
+  if (toolCall.state !== ClientToolCallState.pending) {
+    return false
+  }
+
+  // Never show buttons for tools the user has marked as always-allowed
+  if (useCopilotStore.getState().isToolAutoAllowed(toolCall.name)) {
+    return false
+  }
+
+  const hasInterrupt = !!TOOL_DISPLAY_REGISTRY[toolCall.name]?.uiConfig?.interrupt
+  if (hasInterrupt) {
    return true
  }

-  const instance = getClientTool(toolCall.id)
-  let hasInterrupt = !!instance?.getInterruptDisplays?.()
-  if (!hasInterrupt) {
-    try {
-      const def = getRegisteredTools()[toolCall.name]
-      if (def) {
-        hasInterrupt =
-          typeof def.hasInterrupt === 'function'
-            ? !!def.hasInterrupt(toolCall.params || {})
-            : !!def.hasInterrupt
-      }
-    } catch {}
-  }
-
-  if (hasInterrupt && toolCall.state === 'pending') {
-    return true
-  }
-
-  const mode = useCopilotStore.getState().mode
-  if (mode === 'build' && isIntegrationTool(toolCall.name) && toolCall.state === 'pending') {
+  // Integration tools (user-installed) always require approval
+  if (isIntegrationTool(toolCall.name)) {
    return true
  }

  return false
 }

+const toolCallLogger = createLogger('CopilotToolCall')
+
+async function sendToolDecision(
+  toolCallId: string,
+  status: 'accepted' | 'rejected' | 'background'
+) {
+  try {
+    await fetch('/api/copilot/confirm', {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({ toolCallId, status }),
+    })
+  } catch (error) {
+    toolCallLogger.warn('Failed to send tool decision', {
+      toolCallId,
+      status,
+      error: error instanceof Error ? error.message : String(error),
+    })
+  }
+}
+
 async function handleRun(
  toolCall: CopilotToolCall,
  setToolCallState: any,
  onStateChange?: any,
  editedParams?: any
 ) {
-  const instance = getClientTool(toolCall.id)
+  setToolCallState(toolCall, 'executing', editedParams ? { params: editedParams } : undefined)
+  onStateChange?.('executing')
+  await sendToolDecision(toolCall.id, 'accepted')

-  if (!instance && isIntegrationTool(toolCall.name)) {
-    onStateChange?.('executing')
-    try {
-      await useCopilotStore.getState().executeIntegrationTool(toolCall.id)
-    } catch (e) {
-      setToolCallState(toolCall, 'error', { error: e instanceof Error ? e.message : String(e) })
-      onStateChange?.('error')
-      try {
-        await fetch('/api/copilot/tools/mark-complete', {
-          method: 'POST',
-          headers: { 'Content-Type': 'application/json' },
-          body: JSON.stringify({
-            id: toolCall.id,
-            name: toolCall.name,
-            status: 500,
-            message: e instanceof Error ? e.message : 'Tool execution failed',
-            data: { error: e instanceof Error ? e.message : String(e) },
-          }),
-        })
-      } catch {
-        console.error('[handleRun] Failed to notify backend of tool error:', toolCall.id)
-      }
-    }
-    return
-  }
-
-  if (!instance) return
-  try {
-    const mergedParams =
-      editedParams ||
-      (toolCall as any).params ||
-      (toolCall as any).parameters ||
-      (toolCall as any).input ||
-      {}
-    await instance.handleAccept?.(mergedParams)
-    onStateChange?.('executing')
-  } catch (e) {
-    setToolCallState(toolCall, 'error', { error: e instanceof Error ? e.message : String(e) })
+  // Client-executable run tools: execute on the client for real-time feedback
+  // (block pulsing, console logs, stop button). The server defers execution
+  // for these tools; the client reports back via mark-complete.
+  if (CLIENT_EXECUTABLE_RUN_TOOLS.has(toolCall.name)) {
+    const params = editedParams || toolCall.params || {}
+    executeRunToolOnClient(toolCall.id, toolCall.name, params)
  }
 }

 async function handleSkip(toolCall: CopilotToolCall, setToolCallState: any, onStateChange?: any) {
-  const instance = getClientTool(toolCall.id)
-
-  if (!instance && isIntegrationTool(toolCall.name)) {
-    setToolCallState(toolCall, 'rejected')
-    onStateChange?.('rejected')
-
-    let notified = false
-    for (let attempt = 0; attempt < 3 && !notified; attempt++) {
-      try {
-        const res = await fetch('/api/copilot/tools/mark-complete', {
-          method: 'POST',
-          headers: { 'Content-Type': 'application/json' },
-          body: JSON.stringify({
-            id: toolCall.id,
-            name: toolCall.name,
-            status: 400,
-            message: 'Tool execution skipped by user',
-            data: { skipped: true, reason: 'user_skipped' },
-          }),
-        })
-        if (res.ok) {
-          notified = true
-        }
-      } catch (e) {
-        if (attempt < 2) {
-          await new Promise((resolve) => setTimeout(resolve, 500))
-        }
-      }
-    }
-
-    if (!notified) {
-      console.error('[handleSkip] Failed to notify backend after 3 attempts:', toolCall.id)
-    }
-    return
-  }
-
-  if (instance) {
-    try {
-      await instance.handleReject?.()
-    } catch {}
-  }
  setToolCallState(toolCall, 'rejected')
  onStateChange?.('rejected')
+  await sendToolDecision(toolCall.id, 'rejected')
 }

 function getDisplayName(toolCall: CopilotToolCall): string {
  const fromStore = (toolCall as any).display?.text
  if (fromStore) return fromStore
-  try {
-    const def = getRegisteredTools()[toolCall.name] as any
-    const byState = def?.metadata?.displayNames?.[toolCall.state]
-    if (byState?.text) return byState.text
-  } catch {}
+  const registryEntry = TOOL_DISPLAY_REGISTRY[toolCall.name]
+  const byState = registryEntry?.displayNames?.[toolCall.state as ClientToolCallState]
+  if (byState?.text) return byState.text

  const stateVerb = getStateVerb(toolCall.state)
  const formattedName = formatToolName(toolCall.name)
@@ -1431,9 +1374,7 @@ function RunSkipButtons({
    setButtonsHidden(true)
    try {
      await addAutoAllowedTool(toolCall.name)
-      if (!isIntegrationTool(toolCall.name)) {
-        await handleRun(toolCall, setToolCallState, onStateChange, editedParams)
-      }
+      await handleRun(toolCall, setToolCallState, onStateChange, editedParams)
    } finally {
      setIsProcessing(false)
      actionInProgressRef.current = false
@@ -1507,10 +1448,10 @@ export function ToolCall({
  const paramsRef = useRef(params)

  // Check if this integration tool is auto-allowed
-  // Subscribe to autoAllowedTools so we re-render when it changes
-  const autoAllowedTools = useCopilotStore((s) => s.autoAllowedTools)
-  const { removeAutoAllowedTool } = useCopilotStore()
-  const isAutoAllowed = isIntegrationTool(toolCall.name) && autoAllowedTools.includes(toolCall.name)
+  const { removeAutoAllowedTool, setToolCallState } = useCopilotStore()
+  const isAutoAllowed = useCopilotStore(
+    (s) => isIntegrationTool(toolCall.name) && s.isToolAutoAllowed(toolCall.name)
+  )

  // Update edited params when toolCall params change (deep comparison to avoid resetting user edits on ref change)
  useEffect(() => {
@@ -1526,34 +1467,12 @@ export function ToolCall({
    toolCall.name === 'mark_todo_in_progress' ||
    toolCall.name === 'tool_search_tool_regex' ||
    toolCall.name === 'user_memory' ||
-    toolCall.name === 'edit_respond' ||
-    toolCall.name === 'debug_respond' ||
-    toolCall.name === 'plan_respond' ||
-    toolCall.name === 'research_respond' ||
-    toolCall.name === 'info_respond' ||
-    toolCall.name === 'deploy_respond' ||
-    toolCall.name === 'superagent_respond'
+    toolCall.name.endsWith('_respond')
  )
    return null

  // Special rendering for subagent tools - show as thinking text with tool calls at top level
-  const SUBAGENT_TOOLS = [
-    'plan',
-    'edit',
-    'debug',
-    'test',
-    'deploy',
-    'evaluate',
-    'auth',
-    'research',
-    'knowledge',
-    'custom_tool',
-    'tour',
-    'info',
-    'workflow',
-    'superagent',
-  ]
-  const isSubagentTool = SUBAGENT_TOOLS.includes(toolCall.name)
+  const isSubagentTool = TOOL_DISPLAY_REGISTRY[toolCall.name]?.uiConfig?.subagent === true

  // For ALL subagent tools, don't show anything until we have blocks with content
  if (isSubagentTool) {
@@ -1593,17 +1512,18 @@ export function ToolCall({
    stateStr === 'aborted'

  // Allow rendering if:
-  // 1. Tool is in CLASS_TOOL_METADATA (client tools), OR
+  // 1. Tool is in TOOL_DISPLAY_REGISTRY (client tools), OR
  // 2. We're in build mode (integration tools are executed server-side), OR
  // 3. Tool call is already completed (historical - should always render)
-  const isClientTool = !!CLASS_TOOL_METADATA[toolCall.name]
+  const isClientTool = !!TOOL_DISPLAY_REGISTRY[toolCall.name]
  const isIntegrationToolInBuildMode = mode === 'build' && !isClientTool

  if (!isClientTool && !isIntegrationToolInBuildMode && !isCompletedToolCall) {
    return null
  }
+  const toolUIConfig = TOOL_DISPLAY_REGISTRY[toolCall.name]?.uiConfig
  // Check if tool has params table config (meaning it's expandable)
-  const hasParamsTable = !!getToolUIConfig(toolCall.name)?.paramsTable
+  const hasParamsTable = !!toolUIConfig?.paramsTable
  const isRunWorkflow = toolCall.name === 'run_workflow'
  const isExpandableTool =
    hasParamsTable ||
@@ -1613,7 +1533,6 @@ export function ToolCall({
  const showButtons = isCurrentMessage && shouldShowRunSkipButtons(toolCall)

  // Check UI config for secondary action - only show for current message tool calls
-  const toolUIConfig = getToolUIConfig(toolCall.name)
  const secondaryAction = toolUIConfig?.secondaryAction
  const showSecondaryAction = secondaryAction?.showInStates.includes(
    toolCall.state as ClientToolCallState
@@ -2211,16 +2130,9 @@ export function ToolCall({
        <div className='mt-[10px]'>
          <Button
            onClick={async () => {
-              try {
-                const instance = getClientTool(toolCall.id)
-                instance?.setState?.((ClientToolCallState as any).background)
-                await instance?.markToolComplete?.(
-                  200,
-                  'The user has chosen to move the workflow execution to the background. Check back with them later to know when the workflow execution is complete'
-                )
-                forceUpdate({})
-                onStateChange?.('background')
-              } catch {}
+              setToolCallState(toolCall, ClientToolCallState.background)
+              onStateChange?.('background')
+              await sendToolDecision(toolCall.id, 'background')
            }}
            variant='tertiary'
            title='Move to Background'
@@ -2232,21 +2144,9 @@ export function ToolCall({
        <div className='mt-[10px]'>
          <Button
            onClick={async () => {
-              try {
-                const instance = getClientTool(toolCall.id)
-                const elapsedSeconds = instance?.getElapsedSeconds?.() || 0
-                instance?.setState?.((ClientToolCallState as any).background, {
-                  result: { _elapsedSeconds: elapsedSeconds },
-                })
-                const { updateToolCallParams } = useCopilotStore.getState()
-                updateToolCallParams?.(toolCall.id, { _elapsedSeconds: Math.round(elapsedSeconds) })
-                await instance?.markToolComplete?.(
-                  200,
-                  `User woke you up after ${Math.round(elapsedSeconds)} seconds`
-                )
-                forceUpdate({})
-                onStateChange?.('background')
-              } catch {}
+              setToolCallState(toolCall, ClientToolCallState.background)
+              onStateChange?.('background')
+              await sendToolDecision(toolCall.id, 'background')
            }}
            variant='tertiary'
            title='Wake'
--- a/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/copilot/components/user-input/constants.ts
+++ b/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/copilot/components/user-input/constants.ts
@@ -246,6 +246,7 @@ export function getCommandDisplayLabel(commandId: string): string {
 * Model configuration options
 */
 export const MODEL_OPTIONS = [
+  { value: 'claude-4.6-opus', label: 'Claude 4.6 Opus' },
  { value: 'claude-4.5-opus', label: 'Claude 4.5 Opus' },
  { value: 'claude-4.5-sonnet', label: 'Claude 4.5 Sonnet' },
  { value: 'claude-4.5-haiku', label: 'Claude 4.5 Haiku' },
--- a/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/copilot/copilot.tsx
+++ b/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/copilot/copilot.tsx
@@ -107,13 +107,13 @@ export const Copilot = forwardRef<CopilotRef, CopilotProps>(({ panelWidth }, ref
    currentChat,
    selectChat,
    deleteChat,
-    areChatsFresh,
    workflowId: copilotWorkflowId,
    setPlanTodos,
    closePlanTodos,
    clearPlanArtifact,
    savePlanArtifact,
    loadAutoAllowedTools,
+    resumeActiveStream,
  } = useCopilotStore()

  // Initialize copilot
@@ -126,6 +126,7 @@ export const Copilot = forwardRef<CopilotRef, CopilotProps>(({ panelWidth }, ref
    loadAutoAllowedTools,
    currentChat,
    isSendingMessage,
+    resumeActiveStream,
  })

  // Handle scroll management (80px stickiness for copilot)
@@ -140,7 +141,6 @@ export const Copilot = forwardRef<CopilotRef, CopilotProps>(({ panelWidth }, ref
      activeWorkflowId,
      copilotWorkflowId,
      loadChats,
-      areChatsFresh,
      isSendingMessage,
    }
  )
@@ -421,8 +421,8 @@ export const Copilot = forwardRef<CopilotRef, CopilotProps>(({ panelWidth }, ref
          </div>
        </div>

-        {/* Show loading state until fully initialized */}
-        {!isInitialized ? (
+        {/* Show loading state until fully initialized, but skip if actively streaming (resume case) */}
+        {!isInitialized && !isSendingMessage ? (
          <div className='flex h-full w-full items-center justify-center'>
            <div className='flex flex-col items-center gap-3'>
              <p className='text-muted-foreground text-sm'>Loading copilot</p>
--- a/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/copilot/hooks/use-chat-history.ts
+++ b/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/copilot/hooks/use-chat-history.ts
@@ -10,7 +10,6 @@ interface UseChatHistoryProps {
  activeWorkflowId: string | null
  copilotWorkflowId: string | null
  loadChats: (forceRefresh: boolean) => Promise<void>
-  areChatsFresh: (workflowId: string) => boolean
  isSendingMessage: boolean
 }

@@ -21,8 +20,7 @@ interface UseChatHistoryProps {
 * @returns Chat history utilities
 */
 export function useChatHistory(props: UseChatHistoryProps) {
-  const { chats, activeWorkflowId, copilotWorkflowId, loadChats, areChatsFresh, isSendingMessage } =
-    props
+  const { chats, activeWorkflowId, copilotWorkflowId, loadChats, isSendingMessage } = props

  /** Groups chats by time period (Today, Yesterday, This Week, etc.) */
  const groupedChats = useMemo(() => {
@@ -80,7 +78,7 @@ export function useChatHistory(props: UseChatHistoryProps) {
  /** Handles history dropdown opening and loads chats if needed (non-blocking) */
  const handleHistoryDropdownOpen = useCallback(
    (open: boolean) => {
-      if (open && activeWorkflowId && !isSendingMessage && !areChatsFresh(activeWorkflowId)) {
+      if (open && activeWorkflowId && !isSendingMessage) {
        loadChats(false).catch((error) => {
          logger.error('Failed to load chat history:', error)
        })
@@ -90,7 +88,7 @@ export function useChatHistory(props: UseChatHistoryProps) {
        logger.info('Chat history opened during stream - showing cached data only')
      }
    },
-    [activeWorkflowId, areChatsFresh, isSendingMessage, loadChats]
+    [activeWorkflowId, isSendingMessage, loadChats]
  )

  return {
--- a/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/copilot/hooks/use-copilot-initialization.ts
+++ b/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/copilot/hooks/use-copilot-initialization.ts
@@ -14,6 +14,7 @@ interface UseCopilotInitializationProps {
  loadAutoAllowedTools: () => Promise<void>
  currentChat: any
  isSendingMessage: boolean
+  resumeActiveStream: () => Promise<boolean>
 }

 /**
@@ -32,11 +33,13 @@ export function useCopilotInitialization(props: UseCopilotInitializationProps) {
    loadAutoAllowedTools,
    currentChat,
    isSendingMessage,
+    resumeActiveStream,
  } = props

  const [isInitialized, setIsInitialized] = useState(false)
  const lastWorkflowIdRef = useRef<string | null>(null)
  const hasMountedRef = useRef(false)
+  const hasResumedRef = useRef(false)

  /** Initialize on mount - loads chats if needed. Never loads during streaming */
  useEffect(() => {
@@ -105,6 +108,16 @@ export function useCopilotInitialization(props: UseCopilotInitializationProps) {
    isSendingMessage,
  ])

+  /** Try to resume active stream on mount - runs early, before waiting for chats */
+  useEffect(() => {
+    if (hasResumedRef.current || isSendingMessage) return
+    hasResumedRef.current = true
+    // Resume immediately on mount - don't wait for isInitialized
+    resumeActiveStream().catch((err) => {
+      logger.warn('[Copilot] Failed to resume active stream', err)
+    })
+  }, [isSendingMessage, resumeActiveStream])
+
  /** Load auto-allowed tools once on mount - runs immediately, independent of workflow */
  const hasLoadedAutoAllowedToolsRef = useRef(false)
  useEffect(() => {
--- a/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/utils/workflow-execution-utils.ts
+++ b/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/utils/workflow-execution-utils.ts
@@ -11,6 +11,12 @@ export interface WorkflowExecutionOptions {
  executionId?: string
  onBlockComplete?: (blockId: string, output: any) => Promise<void>
  overrideTriggerType?: 'chat' | 'manual' | 'api'
+  stopAfterBlockId?: string
+  /** For run_from_block / run_block: start from a specific block using cached state */
+  runFromBlock?: {
+    startBlockId: string
+    executionId?: string
+  }
 }

 /**
@@ -39,6 +45,15 @@ export async function executeWorkflowWithFullLogging(
    triggerType: options.overrideTriggerType || 'manual',
    useDraftState: true,
    isClientSession: true,
+    ...(options.stopAfterBlockId ? { stopAfterBlockId: options.stopAfterBlockId } : {}),
+    ...(options.runFromBlock
+      ? {
+          runFromBlock: {
+            startBlockId: options.runFromBlock.startBlockId,
+            executionId: options.runFromBlock.executionId || 'latest',
+          },
+        }
+      : {}),
  }

  const response = await fetch(`/api/workflows/${activeWorkflowId}/execute`, {
--- a/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/workflow.tsx
+++ b/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/workflow.tsx
@@ -18,7 +18,7 @@ import 'reactflow/dist/style.css'
 import { createLogger } from '@sim/logger'
 import { useShallow } from 'zustand/react/shallow'
 import { useSession } from '@/lib/auth/auth-client'
-import type { OAuthConnectEventDetail } from '@/lib/copilot/tools/client/other/oauth-request-access'
+import type { OAuthConnectEventDetail } from '@/lib/copilot/tools/client/base-tool'
 import type { OAuthProvider } from '@/lib/oauth'
 import { BLOCK_DIMENSIONS, CONTAINER_DIMENSIONS } from '@/lib/workflows/blocks/block-dimensions'
 import { TriggerUtils } from '@/lib/workflows/triggers/triggers'