diff --git a/apps/sim/app/api/copilot/headless/route.ts b/apps/sim/app/api/copilot/headless/route.ts
new file mode 100644
index 000000000..9735b4859
--- /dev/null
+++ b/apps/sim/app/api/copilot/headless/route.ts
@@ -0,0 +1,364 @@
+import { db } from '@sim/db'
+import { copilotChats, workflow as workflowTable } from '@sim/db/schema'
+import { createLogger } from '@sim/logger'
+import { eq } from 'drizzle-orm'
+import { type NextRequest, NextResponse } from 'next/server'
+import { z } from 'zod'
+import { authenticateApiKeyFromHeader, updateApiKeyLastUsed } from '@/lib/api-key/service'
+import { getSession } from '@/lib/auth'
+import { getCopilotModel } from '@/lib/copilot/config'
+import { SIM_AGENT_API_URL_DEFAULT, SIM_AGENT_VERSION } from '@/lib/copilot/constants'
+import { COPILOT_MODEL_IDS } from '@/lib/copilot/models'
+import {
+  createRequestTracker,
+  createUnauthorizedResponse,
+} from '@/lib/copilot/request-helpers'
+import {
+  createStream,
+  completeStream,
+  errorStream,
+  updateStreamStatus,
+} from '@/lib/copilot/stream-persistence'
+import { executeToolServerSide, isServerExecutableTool } from '@/lib/copilot/tools/server/executor'
+import { getCredentialsServerTool } from '@/lib/copilot/tools/server/user/get-credentials'
+import { loadWorkflowFromNormalizedTables } from '@/lib/workflows/persistence/utils'
+import { sanitizeForCopilot } from '@/lib/workflows/sanitization/json-sanitizer'
+import { env } from '@/lib/core/config/env'
+import { tools } from '@/tools/registry'
+import { getLatestVersionTools, stripVersionSuffix } from '@/tools/utils'
+
+const logger = createLogger('HeadlessCopilotAPI')
+
+const SIM_AGENT_API_URL = env.SIM_AGENT_API_URL || SIM_AGENT_API_URL_DEFAULT
+
+const HeadlessRequestSchema = z.object({
+  message: z.string().min(1, 'Message is required'),
+  workflowId: z.string().min(1, 'Workflow ID is required'),
+  chatId: z.string().optional(),
+  model: z.enum(COPILOT_MODEL_IDS).optional(),
+  mode: z.enum(['agent', 'build', 'chat']).optional().default('agent'),
+  timeout: z.number().optional().default(300000), // 5 minute default
+  persistChanges: z.boolean().optional().default(true),
+  createNewChat: z.boolean().optional().default(false),
+})
+
+export const dynamic = 'force-dynamic'
+export const fetchCache = 'force-no-store'
+export const runtime = 'nodejs'
+
+/**
+ * POST /api/copilot/headless
+ *
+ * Execute copilot completely server-side without any client connection.
+ * All tool calls are executed server-side and results are persisted directly.
+ *
+ * Returns the final result after all processing is complete.
+ */
+export async function POST(req: NextRequest) {
+  const tracker = createRequestTracker()
+  const startTime = Date.now()
+
+  try {
+    // Authenticate via session or API key
+    let userId: string | null = null
+
+    const session = await getSession()
+    if (session?.user?.id) {
+      userId = session.user.id
+    } else {
+      // Try API key authentication from header
+      const apiKey = req.headers.get('x-api-key')
+      if (apiKey) {
+        const authResult = await authenticateApiKeyFromHeader(apiKey)
+        if (authResult.success && authResult.userId) {
+          userId = authResult.userId
+          // Update last used timestamp in background
+          if (authResult.keyId) {
+            updateApiKeyLastUsed(authResult.keyId).catch(() => {})
+          }
+        }
+      }
+    }
+
+    if (!userId) {
+      return createUnauthorizedResponse()
+    }
+
+    const body = await req.json()
+    const { message, workflowId, chatId, model, mode, timeout, persistChanges, createNewChat } =
+      HeadlessRequestSchema.parse(body)
+
+    logger.info(`[${tracker.requestId}] Headless copilot request`, {
+      userId,
+      workflowId,
+      messageLength: message.length,
+      mode,
+    })
+
+    // Verify user has access to workflow
+    const [wf] = await db
+      .select({ userId: workflowTable.userId, workspaceId: workflowTable.workspaceId })
+      .from(workflowTable)
+      .where(eq(workflowTable.id, workflowId))
+      .limit(1)
+
+    if (!wf) {
+      return NextResponse.json({ error: 'Workflow not found' }, { status: 404 })
+    }
+
+    // TODO: Add proper workspace access check
+    if (wf.userId !== userId) {
+      return NextResponse.json({ error: 'Access denied' }, { status: 403 })
+    }
+
+    // Load current workflow state from database
+    const workflowData = await loadWorkflowFromNormalizedTables(workflowId)
+    if (!workflowData) {
+      return NextResponse.json({ error: 'Workflow data not found' }, { status: 404 })
+    }
+
+    const sanitizedWorkflow = sanitizeForCopilot({
+      blocks: workflowData.blocks,
+      edges: workflowData.edges,
+      loops: workflowData.loops,
+      parallels: workflowData.parallels,
+    })
+
+    // Create a stream for tracking (even in headless mode)
+    const streamId = crypto.randomUUID()
+    const userMessageId = crypto.randomUUID()
+    const assistantMessageId = crypto.randomUUID()
+
+    await createStream({
+      streamId,
+      chatId: chatId || '',
+      userId,
+      workflowId,
+      userMessageId,
+      isClientSession: false, // Key: this is headless
+    })
+
+    await updateStreamStatus(streamId, 'streaming')
+
+    // Handle chat persistence
+    let actualChatId = chatId
+    if (createNewChat && !chatId) {
+      const { provider, model: defaultModel } = getCopilotModel('chat')
+      const [newChat] = await db
+        .insert(copilotChats)
+        .values({
+          userId,
+          workflowId,
+          title: null,
+          model: model || defaultModel,
+          messages: [],
+        })
+        .returning()
+
+      if (newChat) {
+        actualChatId = newChat.id
+      }
+    }
+
+    // Get credentials for tools
+    let credentials: {
+      oauth: Record<string, { accessToken: string; accountId: string; name: string }>
+      apiKeys: string[]
+    } | null = null
+
+    try {
+      const rawCredentials = await getCredentialsServerTool.execute({ workflowId }, { userId })
+      const oauthMap: Record<string, { accessToken: string; accountId: string; name: string }> = {}
+
+      for (const cred of rawCredentials?.oauth?.connected?.credentials || []) {
+        if (cred.accessToken) {
+          oauthMap[cred.provider] = {
+            accessToken: cred.accessToken,
+            accountId: cred.id,
+            name: cred.name,
+          }
+        }
+      }
+
+      credentials = {
+        oauth: oauthMap,
+        apiKeys: rawCredentials?.environment?.variableNames || [],
+      }
+    } catch (error) {
+      logger.warn(`[${tracker.requestId}] Failed to fetch credentials`, { error })
+    }
+
+    // Build tool definitions
+    const { createUserToolSchema } = await import('@/tools/params')
+    const latestTools = getLatestVersionTools(tools)
+    const integrationTools = Object.entries(latestTools).map(([toolId, toolConfig]) => {
+      const userSchema = createUserToolSchema(toolConfig)
+      const strippedName = stripVersionSuffix(toolId)
+      return {
+        name: strippedName,
+        description: toolConfig.description || toolConfig.name || strippedName,
+        input_schema: userSchema,
+        defer_loading: true,
+      }
+    })
+
+    // Build request payload
+    const defaults = getCopilotModel('chat')
+    const selectedModel = model || defaults.model
+    const effectiveMode = mode === 'agent' ? 'build' : mode
+
+    const requestPayload = {
+      message,
+      workflowId,
+      userId,
+      stream: false, // Non-streaming for headless
+      model: selectedModel,
+      mode: effectiveMode,
+      version: SIM_AGENT_VERSION,
+      messageId: userMessageId,
+      ...(actualChatId && { chatId: actualChatId }),
+      ...(integrationTools.length > 0 && { tools: integrationTools }),
+      ...(credentials && { credentials }),
+    }
+
+    // Call sim agent (non-streaming)
+    const controller = new AbortController()
+    const timeoutId = setTimeout(() => controller.abort(), timeout)
+
+    try {
+      const response = await fetch(`${SIM_AGENT_API_URL}/api/chat-completion`, {
+        method: 'POST',
+        headers: {
+          'Content-Type': 'application/json',
+          ...(env.COPILOT_API_KEY ? { 'x-api-key': env.COPILOT_API_KEY } : {}),
+        },
+        body: JSON.stringify(requestPayload),
+        signal: controller.signal,
+      })
+
+      clearTimeout(timeoutId)
+
+      if (!response.ok) {
+        const errorText = await response.text()
+        logger.error(`[${tracker.requestId}] Sim agent error`, {
+          status: response.status,
+          error: errorText,
+        })
+        await errorStream(streamId, `Agent error: ${response.statusText}`)
+        return NextResponse.json(
+          { error: `Agent error: ${response.statusText}` },
+          { status: response.status }
+        )
+      }
+
+      const result = await response.json()
+
+      // Execute tool calls server-side
+      const toolResults: Record<string, { success: boolean; result?: unknown; error?: string }> = {}
+
+      if (result.toolCalls && Array.isArray(result.toolCalls)) {
+        for (const toolCall of result.toolCalls) {
+          const toolName = toolCall.name
+          const toolArgs = toolCall.arguments || toolCall.input || {}
+
+          logger.info(`[${tracker.requestId}] Executing tool server-side`, {
+            toolName,
+            toolCallId: toolCall.id,
+          })
+
+          if (!isServerExecutableTool(toolName)) {
+            logger.warn(`[${tracker.requestId}] Tool not executable server-side`, { toolName })
+            toolResults[toolCall.id] = {
+              success: false,
+              error: `Tool ${toolName} requires client-side execution`,
+            }
+            continue
+          }
+
+          const toolResult = await executeToolServerSide(
+            { name: toolName, args: toolArgs },
+            { workflowId, userId, persistChanges }
+          )
+
+          toolResults[toolCall.id] = toolResult
+        }
+      }
+
+      // Mark stream complete
+      await completeStream(streamId, { content: result.content, toolResults })
+
+      // Save to chat history
+      if (actualChatId && persistChanges) {
+        const [chat] = await db
+          .select()
+          .from(copilotChats)
+          .where(eq(copilotChats.id, actualChatId))
+          .limit(1)
+
+        const existingMessages = chat ? (Array.isArray(chat.messages) ? chat.messages : []) : []
+
+        const newMessages = [
+          ...existingMessages,
+          {
+            id: userMessageId,
+            role: 'user',
+            content: message,
+            timestamp: new Date().toISOString(),
+          },
+          {
+            id: assistantMessageId,
+            role: 'assistant',
+            content: result.content,
+            timestamp: new Date().toISOString(),
+            toolCalls: Object.entries(toolResults).map(([id, r]) => ({
+              id,
+              success: r.success,
+            })),
+          },
+        ]
+
+        await db
+          .update(copilotChats)
+          .set({ messages: newMessages, updatedAt: new Date() })
+          .where(eq(copilotChats.id, actualChatId))
+      }
+
+      const duration = Date.now() - startTime
+      logger.info(`[${tracker.requestId}] Headless copilot complete`, {
+        duration,
+        contentLength: result.content?.length || 0,
+        toolCallsExecuted: Object.keys(toolResults).length,
+      })
+
+      return NextResponse.json({
+        success: true,
+        streamId,
+        chatId: actualChatId,
+        content: result.content,
+        toolResults,
+        duration,
+      })
+    } catch (error) {
+      clearTimeout(timeoutId)
+
+      if (error instanceof Error && error.name === 'AbortError') {
+        await errorStream(streamId, 'Request timed out')
+        return NextResponse.json({ error: 'Request timed out' }, { status: 504 })
+      }
+
+      throw error
+    }
+  } catch (error) {
+    logger.error(`[${tracker.requestId}] Headless copilot error`, { error })
+
+    if (error instanceof z.ZodError) {
+      return NextResponse.json({ error: 'Invalid request', details: error.errors }, { status: 400 })
+    }
+
+    return NextResponse.json(
+      { error: error instanceof Error ? error.message : 'Internal error' },
+      { status: 500 }
+    )
+  }
+}
+
diff --git a/apps/sim/app/api/copilot/stream/[streamId]/route.ts b/apps/sim/app/api/copilot/stream/[streamId]/route.ts
new file mode 100644
index 000000000..62e0a15f1
--- /dev/null
+++ b/apps/sim/app/api/copilot/stream/[streamId]/route.ts
@@ -0,0 +1,237 @@
+import { createLogger } from '@sim/logger'
+import { type NextRequest, NextResponse } from 'next/server'
+import { getSession } from '@/lib/auth'
+import {
+  getStreamMetadata,
+  getStreamEvents,
+  getStreamEventCount,
+  getToolCallStates,
+  refreshStreamTTL,
+  checkAbortSignal,
+  abortStream,
+} from '@/lib/copilot/stream-persistence'
+
+const logger = createLogger('StreamResumeAPI')
+
+interface RouteParams {
+  streamId: string
+}
+
+/**
+ * GET /api/copilot/stream/{streamId}
+ * Subscribe to or resume a stream
+ *
+ * Query params:
+ * - offset: Start from this event index (for resumption)
+ * - mode: 'sse' (default) or 'poll'
+ */
+export async function GET(req: NextRequest, { params }: { params: Promise<RouteParams> }) {
+  const { streamId } = await params
+  const session = await getSession()
+
+  if (!session?.user?.id) {
+    return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
+  }
+
+  const metadata = await getStreamMetadata(streamId)
+  if (!metadata) {
+    return NextResponse.json({ error: 'Stream not found' }, { status: 404 })
+  }
+
+  // Verify user owns this stream
+  if (metadata.userId !== session.user.id) {
+    return NextResponse.json({ error: 'Forbidden' }, { status: 403 })
+  }
+
+  const offset = parseInt(req.nextUrl.searchParams.get('offset') || '0', 10)
+  const mode = req.nextUrl.searchParams.get('mode') || 'sse'
+
+  // Refresh TTL since someone is actively consuming
+  await refreshStreamTTL(streamId)
+
+  // Poll mode: return current state as JSON
+  if (mode === 'poll') {
+    const events = await getStreamEvents(streamId, offset)
+    const toolCalls = await getToolCallStates(streamId)
+    const eventCount = await getStreamEventCount(streamId)
+
+    return NextResponse.json({
+      metadata,
+      events,
+      toolCalls,
+      totalEvents: eventCount,
+      nextOffset: offset + events.length,
+    })
+  }
+
+  // SSE mode: stream events
+  const encoder = new TextEncoder()
+
+  const readable = new ReadableStream({
+    async start(controller) {
+      let closed = false
+
+      const safeEnqueue = (data: string) => {
+        if (closed) return
+        try {
+          controller.enqueue(encoder.encode(data))
+        } catch {
+          closed = true
+        }
+      }
+
+      const safeClose = () => {
+        if (closed) return
+        closed = true
+        try {
+          controller.close()
+        } catch {
+          // Already closed
+        }
+      }
+
+      // Send initial connection event
+      safeEnqueue(`: connected\n\n`)
+
+      // Send metadata
+      safeEnqueue(`event: metadata\ndata: ${JSON.stringify(metadata)}\n\n`)
+
+      // Send tool call states
+      const toolCalls = await getToolCallStates(streamId)
+      if (Object.keys(toolCalls).length > 0) {
+        safeEnqueue(`event: tool_states\ndata: ${JSON.stringify(toolCalls)}\n\n`)
+      }
+
+      // Replay missed events
+      const missedEvents = await getStreamEvents(streamId, offset)
+      for (const event of missedEvents) {
+        safeEnqueue(event)
+      }
+
+      // If stream is complete, send done and close
+      if (metadata.status === 'complete' || metadata.status === 'error' || metadata.status === 'aborted') {
+        safeEnqueue(
+          `event: stream_status\ndata: ${JSON.stringify({
+            status: metadata.status,
+            error: metadata.error,
+          })}\n\n`
+        )
+        safeClose()
+        return
+      }
+
+      // Stream is still active - poll for new events
+      let lastOffset = offset + missedEvents.length
+      const pollInterval = 100 // 100ms
+      const maxPollTime = 5 * 60 * 1000 // 5 minutes max
+      const startTime = Date.now()
+
+      const poll = async () => {
+        if (closed) return
+
+        try {
+          // Check for timeout
+          if (Date.now() - startTime > maxPollTime) {
+            logger.info('Stream poll timeout', { streamId })
+            safeEnqueue(
+              `event: stream_status\ndata: ${JSON.stringify({ status: 'timeout' })}\n\n`
+            )
+            safeClose()
+            return
+          }
+
+          // Check if client disconnected
+          if (await checkAbortSignal(streamId)) {
+            safeEnqueue(
+              `event: stream_status\ndata: ${JSON.stringify({ status: 'aborted' })}\n\n`
+            )
+            safeClose()
+            return
+          }
+
+          // Get current metadata to check status
+          const currentMeta = await getStreamMetadata(streamId)
+          if (!currentMeta) {
+            safeClose()
+            return
+          }
+
+          // Get new events
+          const newEvents = await getStreamEvents(streamId, lastOffset)
+          for (const event of newEvents) {
+            safeEnqueue(event)
+          }
+          lastOffset += newEvents.length
+
+          // Refresh TTL
+          await refreshStreamTTL(streamId)
+
+          // If complete, send status and close
+          if (
+            currentMeta.status === 'complete' ||
+            currentMeta.status === 'error' ||
+            currentMeta.status === 'aborted'
+          ) {
+            safeEnqueue(
+              `event: stream_status\ndata: ${JSON.stringify({
+                status: currentMeta.status,
+                error: currentMeta.error,
+              })}\n\n`
+            )
+            safeClose()
+            return
+          }
+
+          // Continue polling
+          setTimeout(poll, pollInterval)
+        } catch (error) {
+          logger.error('Stream poll error', { streamId, error })
+          safeClose()
+        }
+      }
+
+      // Start polling
+      setTimeout(poll, pollInterval)
+    },
+  })
+
+  return new Response(readable, {
+    headers: {
+      'Content-Type': 'text/event-stream; charset=utf-8',
+      'Cache-Control': 'no-cache, no-transform',
+      Connection: 'keep-alive',
+      'X-Accel-Buffering': 'no',
+      'X-Stream-Id': streamId,
+    },
+  })
+}
+
+/**
+ * DELETE /api/copilot/stream/{streamId}
+ * Abort a stream
+ */
+export async function DELETE(req: NextRequest, { params }: { params: Promise<RouteParams> }) {
+  const { streamId } = await params
+  const session = await getSession()
+
+  if (!session?.user?.id) {
+    return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
+  }
+
+  const metadata = await getStreamMetadata(streamId)
+  if (!metadata) {
+    return NextResponse.json({ error: 'Stream not found' }, { status: 404 })
+  }
+
+  // Verify user owns this stream
+  if (metadata.userId !== session.user.id) {
+    return NextResponse.json({ error: 'Forbidden' }, { status: 403 })
+  }
+
+  await abortStream(streamId)
+
+  logger.info('Stream aborted by user', { streamId, userId: session.user.id })
+
+  return NextResponse.json({ success: true, streamId })
+}
+
diff --git a/apps/sim/lib/copilot/api.ts b/apps/sim/lib/copilot/api.ts
index c680f9751..12021699c 100644
--- a/apps/sim/lib/copilot/api.ts
+++ b/apps/sim/lib/copilot/api.ts
@@ -98,6 +98,8 @@ export interface ApiResponse {
  */
 export interface StreamingResponse extends ApiResponse {
   stream?: ReadableStream
+  streamId?: string
+  chatId?: string
 }
 
 /**
@@ -163,9 +165,15 @@ export async function sendStreamingMessage(
       }
     }
 
+    // Extract stream and chat IDs from headers for resumption support
+    const streamId = response.headers.get('X-Stream-Id') || undefined
+    const chatId = response.headers.get('X-Chat-Id') || undefined
+
     return {
       success: true,
       stream: response.body,
+      streamId,
+      chatId,
     }
   } catch (error) {
     // Handle AbortError gracefully - this is expected when user aborts
diff --git a/apps/sim/lib/copilot/render-events.ts b/apps/sim/lib/copilot/render-events.ts
new file mode 100644
index 000000000..8afd3a519
--- /dev/null
+++ b/apps/sim/lib/copilot/render-events.ts
@@ -0,0 +1,324 @@
+/**
+ * Render events are the normalized event types sent to clients.
+ * These are independent of the sim agent's internal event format.
+ */
+
+export type RenderEventType =
+  | 'text_delta'
+  | 'text_complete'
+  | 'tool_pending'
+  | 'tool_executing'
+  | 'tool_success'
+  | 'tool_error'
+  | 'tool_result'
+  | 'subagent_start'
+  | 'subagent_text'
+  | 'subagent_tool_call'
+  | 'subagent_end'
+  | 'thinking_start'
+  | 'thinking_delta'
+  | 'thinking_end'
+  | 'message_start'
+  | 'message_complete'
+  | 'chat_id'
+  | 'conversation_id'
+  | 'error'
+  | 'stream_status'
+
+export interface BaseRenderEvent {
+  type: RenderEventType
+  timestamp?: number
+}
+
+export interface TextDeltaEvent extends BaseRenderEvent {
+  type: 'text_delta'
+  content: string
+}
+
+export interface TextCompleteEvent extends BaseRenderEvent {
+  type: 'text_complete'
+  content: string
+}
+
+export interface ToolPendingEvent extends BaseRenderEvent {
+  type: 'tool_pending'
+  toolCallId: string
+  toolName: string
+  args?: Record<string, unknown>
+  display?: {
+    label: string
+    icon?: string
+  }
+}
+
+export interface ToolExecutingEvent extends BaseRenderEvent {
+  type: 'tool_executing'
+  toolCallId: string
+  toolName: string
+}
+
+export interface ToolSuccessEvent extends BaseRenderEvent {
+  type: 'tool_success'
+  toolCallId: string
+  toolName: string
+  result?: unknown
+  display?: {
+    label: string
+    icon?: string
+  }
+}
+
+export interface ToolErrorEvent extends BaseRenderEvent {
+  type: 'tool_error'
+  toolCallId: string
+  toolName: string
+  error: string
+  display?: {
+    label: string
+    icon?: string
+  }
+}
+
+export interface ToolResultEvent extends BaseRenderEvent {
+  type: 'tool_result'
+  toolCallId: string
+  success: boolean
+  result?: unknown
+  error?: string
+  failedDependency?: boolean
+  skipped?: boolean
+}
+
+export interface SubagentStartEvent extends BaseRenderEvent {
+  type: 'subagent_start'
+  parentToolCallId: string
+  subagentName: string
+}
+
+export interface SubagentTextEvent extends BaseRenderEvent {
+  type: 'subagent_text'
+  parentToolCallId: string
+  content: string
+}
+
+export interface SubagentToolCallEvent extends BaseRenderEvent {
+  type: 'subagent_tool_call'
+  parentToolCallId: string
+  toolCallId: string
+  toolName: string
+  args?: Record<string, unknown>
+  state: 'pending' | 'executing' | 'success' | 'error'
+  result?: unknown
+  error?: string
+}
+
+export interface SubagentEndEvent extends BaseRenderEvent {
+  type: 'subagent_end'
+  parentToolCallId: string
+}
+
+export interface ThinkingStartEvent extends BaseRenderEvent {
+  type: 'thinking_start'
+}
+
+export interface ThinkingDeltaEvent extends BaseRenderEvent {
+  type: 'thinking_delta'
+  content: string
+}
+
+export interface ThinkingEndEvent extends BaseRenderEvent {
+  type: 'thinking_end'
+}
+
+export interface MessageStartEvent extends BaseRenderEvent {
+  type: 'message_start'
+  messageId: string
+}
+
+export interface MessageCompleteEvent extends BaseRenderEvent {
+  type: 'message_complete'
+  messageId: string
+  content?: string
+}
+
+export interface ChatIdEvent extends BaseRenderEvent {
+  type: 'chat_id'
+  chatId: string
+}
+
+export interface ConversationIdEvent extends BaseRenderEvent {
+  type: 'conversation_id'
+  conversationId: string
+}
+
+export interface ErrorEvent extends BaseRenderEvent {
+  type: 'error'
+  error: string
+  code?: string
+}
+
+export interface StreamStatusEvent extends BaseRenderEvent {
+  type: 'stream_status'
+  status: 'streaming' | 'complete' | 'error' | 'aborted'
+  error?: string
+}
+
+export type RenderEvent =
+  | TextDeltaEvent
+  | TextCompleteEvent
+  | ToolPendingEvent
+  | ToolExecutingEvent
+  | ToolSuccessEvent
+  | ToolErrorEvent
+  | ToolResultEvent
+  | SubagentStartEvent
+  | SubagentTextEvent
+  | SubagentToolCallEvent
+  | SubagentEndEvent
+  | ThinkingStartEvent
+  | ThinkingDeltaEvent
+  | ThinkingEndEvent
+  | MessageStartEvent
+  | MessageCompleteEvent
+  | ChatIdEvent
+  | ConversationIdEvent
+  | ErrorEvent
+  | StreamStatusEvent
+
+/**
+ * Serialize a render event to SSE format
+ */
+export function serializeRenderEvent(event: RenderEvent): string {
+  const eventWithTimestamp = {
+    ...event,
+    timestamp: event.timestamp || Date.now(),
+  }
+  return `event: ${event.type}\ndata: ${JSON.stringify(eventWithTimestamp)}\n\n`
+}
+
+/**
+ * Parse an SSE chunk into a render event
+ */
+export function parseRenderEvent(chunk: string): RenderEvent | null {
+  // SSE format: "event: <type>\ndata: <json>\n\n"
+  const lines = chunk.trim().split('\n')
+  let eventType: string | null = null
+  let data: string | null = null
+
+  for (const line of lines) {
+    if (line.startsWith('event: ')) {
+      eventType = line.slice(7)
+    } else if (line.startsWith('data: ')) {
+      data = line.slice(6)
+    }
+  }
+
+  if (!data) return null
+
+  try {
+    const parsed = JSON.parse(data)
+    // If we extracted an event type from SSE, use it; otherwise use from data
+    if (eventType && !parsed.type) {
+      parsed.type = eventType
+    }
+    return parsed as RenderEvent
+  } catch {
+    return null
+  }
+}
+
+/**
+ * Create a text delta event
+ */
+export function createTextDelta(content: string): TextDeltaEvent {
+  return { type: 'text_delta', content, timestamp: Date.now() }
+}
+
+/**
+ * Create a tool pending event
+ */
+export function createToolPending(
+  toolCallId: string,
+  toolName: string,
+  args?: Record<string, unknown>,
+  display?: { label: string; icon?: string }
+): ToolPendingEvent {
+  return {
+    type: 'tool_pending',
+    toolCallId,
+    toolName,
+    args,
+    display,
+    timestamp: Date.now(),
+  }
+}
+
+/**
+ * Create a tool executing event
+ */
+export function createToolExecuting(toolCallId: string, toolName: string): ToolExecutingEvent {
+  return { type: 'tool_executing', toolCallId, toolName, timestamp: Date.now() }
+}
+
+/**
+ * Create a tool success event
+ */
+export function createToolSuccess(
+  toolCallId: string,
+  toolName: string,
+  result?: unknown,
+  display?: { label: string; icon?: string }
+): ToolSuccessEvent {
+  return {
+    type: 'tool_success',
+    toolCallId,
+    toolName,
+    result,
+    display,
+    timestamp: Date.now(),
+  }
+}
+
+/**
+ * Create a tool error event
+ */
+export function createToolError(
+  toolCallId: string,
+  toolName: string,
+  error: string,
+  display?: { label: string; icon?: string }
+): ToolErrorEvent {
+  return {
+    type: 'tool_error',
+    toolCallId,
+    toolName,
+    error,
+    display,
+    timestamp: Date.now(),
+  }
+}
+
+/**
+ * Create a message complete event
+ */
+export function createMessageComplete(messageId: string, content?: string): MessageCompleteEvent {
+  return { type: 'message_complete', messageId, content, timestamp: Date.now() }
+}
+
+/**
+ * Create a stream status event
+ */
+export function createStreamStatus(
+  status: 'streaming' | 'complete' | 'error' | 'aborted',
+  error?: string
+): StreamStatusEvent {
+  return { type: 'stream_status', status, error, timestamp: Date.now() }
+}
+
+/**
+ * Create an error event
+ */
+export function createError(error: string, code?: string): ErrorEvent {
+  return { type: 'error', error, code, timestamp: Date.now() }
+}
+
diff --git a/apps/sim/lib/copilot/stream-client.ts b/apps/sim/lib/copilot/stream-client.ts
new file mode 100644
index 000000000..614fb1dc0
--- /dev/null
+++ b/apps/sim/lib/copilot/stream-client.ts
@@ -0,0 +1,299 @@
+'use client'
+
+import { createLogger } from '@sim/logger'
+
+const logger = createLogger('StreamClient')
+
+export interface StreamMetadata {
+  streamId: string
+  chatId: string
+  userId: string
+  workflowId: string
+  userMessageId: string
+  assistantMessageId?: string
+  status: 'pending' | 'streaming' | 'complete' | 'error' | 'aborted'
+  isClientSession: boolean
+  createdAt: number
+  updatedAt: number
+  completedAt?: number
+  error?: string
+}
+
+export interface StreamResumeResponse {
+  metadata: StreamMetadata
+  events: string[]
+  toolCalls: Record<string, unknown>
+  totalEvents: number
+  nextOffset: number
+}
+
+const STREAM_ID_STORAGE_KEY = 'copilot:activeStream'
+const RECONNECT_DELAY_MS = 1000
+const MAX_RECONNECT_ATTEMPTS = 5
+
+/**
+ * Store active stream info for potential resumption
+ */
+export function storeActiveStream(
+  chatId: string,
+  streamId: string,
+  messageId: string
+): void {
+  try {
+    const data = { chatId, streamId, messageId, storedAt: Date.now() }
+    sessionStorage.setItem(STREAM_ID_STORAGE_KEY, JSON.stringify(data))
+    logger.info('Stored active stream for potential resumption', { streamId, chatId })
+  } catch {
+    // Session storage not available
+  }
+}
+
+/**
+ * Get stored active stream if one exists
+ */
+export function getStoredActiveStream(): {
+  chatId: string
+  streamId: string
+  messageId: string
+  storedAt: number
+} | null {
+  try {
+    const data = sessionStorage.getItem(STREAM_ID_STORAGE_KEY)
+    if (!data) return null
+    return JSON.parse(data)
+  } catch {
+    return null
+  }
+}
+
+/**
+ * Clear stored active stream
+ */
+export function clearStoredActiveStream(): void {
+  try {
+    sessionStorage.removeItem(STREAM_ID_STORAGE_KEY)
+  } catch {
+    // Session storage not available
+  }
+}
+
+/**
+ * Check if a stream is still active
+ */
+export async function checkStreamStatus(streamId: string): Promise<StreamMetadata | null> {
+  try {
+    const response = await fetch(`/api/copilot/stream/${streamId}?mode=poll&offset=0`)
+    if (!response.ok) {
+      if (response.status === 404) {
+        // Stream not found or expired
+        return null
+      }
+      throw new Error(`Failed to check stream status: ${response.statusText}`)
+    }
+    const data: StreamResumeResponse = await response.json()
+    return data.metadata
+  } catch (error) {
+    logger.error('Failed to check stream status', { streamId, error })
+    return null
+  }
+}
+
+/**
+ * Resume a stream from a given offset using SSE
+ */
+export async function resumeStream(
+  streamId: string,
+  offset: number = 0
+): Promise<ReadableStream<Uint8Array> | null> {
+  try {
+    const response = await fetch(`/api/copilot/stream/${streamId}?mode=sse&offset=${offset}`)
+    if (!response.ok || !response.body) {
+      if (response.status === 404) {
+        logger.info('Stream not found for resumption', { streamId })
+        clearStoredActiveStream()
+        return null
+      }
+      throw new Error(`Failed to resume stream: ${response.statusText}`)
+    }
+
+    logger.info('Stream resumption started', { streamId, offset })
+    return response.body
+  } catch (error) {
+    logger.error('Failed to resume stream', { streamId, error })
+    return null
+  }
+}
+
+/**
+ * Abort a stream
+ */
+export async function abortStream(streamId: string): Promise<boolean> {
+  try {
+    const response = await fetch(`/api/copilot/stream/${streamId}`, {
+      method: 'DELETE',
+    })
+    if (!response.ok && response.status !== 404) {
+      throw new Error(`Failed to abort stream: ${response.statusText}`)
+    }
+    clearStoredActiveStream()
+    return true
+  } catch (error) {
+    logger.error('Failed to abort stream', { streamId, error })
+    return false
+  }
+}
+
+export interface StreamSubscription {
+  unsubscribe: () => void
+  getStreamId: () => string
+}
+
+export interface StreamEventHandler {
+  onEvent: (event: { type: string; data: Record<string, unknown> }) => void
+  onError?: (error: Error) => void
+  onComplete?: () => void
+}
+
+/**
+ * Subscribe to a stream (new or resumed) and process events
+ * This provides a unified interface for both initial streams and resumed streams
+ */
+export function subscribeToStream(
+  streamBody: ReadableStream<Uint8Array>,
+  handlers: StreamEventHandler
+): StreamSubscription {
+  const reader = streamBody.getReader()
+  const decoder = new TextDecoder()
+  let cancelled = false
+  let buffer = ''
+  let streamId = ''
+
+  const processEvents = async () => {
+    try {
+      while (!cancelled) {
+        const { done, value } = await reader.read()
+        if (done || cancelled) break
+
+        buffer += decoder.decode(value, { stream: true })
+
+        // Process complete SSE messages
+        const messages = buffer.split('\n\n')
+        buffer = messages.pop() || ''
+
+        for (const message of messages) {
+          if (!message.trim()) continue
+          if (message.startsWith(':')) continue // SSE comment (ping)
+
+          // Parse SSE format
+          const lines = message.split('\n')
+          let eventType = 'message'
+          let data: Record<string, unknown> = {}
+
+          for (const line of lines) {
+            if (line.startsWith('event: ')) {
+              eventType = line.slice(7)
+            } else if (line.startsWith('data: ')) {
+              try {
+                data = JSON.parse(line.slice(6))
+              } catch {
+                data = { raw: line.slice(6) }
+              }
+            }
+          }
+
+          // Track stream ID if provided in metadata
+          if (eventType === 'metadata' && data.streamId) {
+            streamId = data.streamId as string
+          }
+
+          handlers.onEvent({ type: eventType, data })
+
+          // Check for terminal events
+          if (eventType === 'stream_status') {
+            const status = data.status as string
+            if (status === 'complete' || status === 'error' || status === 'aborted') {
+              if (status === 'error' && handlers.onError) {
+                handlers.onError(new Error(data.error as string || 'Stream error'))
+              }
+              if (handlers.onComplete) {
+                handlers.onComplete()
+              }
+              clearStoredActiveStream()
+              return
+            }
+          }
+        }
+      }
+
+      // Stream ended without explicit status
+      if (handlers.onComplete) {
+        handlers.onComplete()
+      }
+    } catch (error) {
+      if (!cancelled && handlers.onError) {
+        handlers.onError(error instanceof Error ? error : new Error(String(error)))
+      }
+    } finally {
+      reader.releaseLock()
+    }
+  }
+
+  // Start processing
+  processEvents()
+
+  return {
+    unsubscribe: () => {
+      cancelled = true
+      reader.cancel().catch(() => {})
+      clearStoredActiveStream()
+    },
+    getStreamId: () => streamId,
+  }
+}
+
+/**
+ * Attempt to resume any active stream from session storage
+ * Returns handlers if resumption is possible, null otherwise
+ */
+export async function attemptStreamResumption(): Promise<{
+  stream: ReadableStream<Uint8Array>
+  metadata: StreamMetadata
+  offset: number
+} | null> {
+  const stored = getStoredActiveStream()
+  if (!stored) return null
+
+  // Check if stream is still valid (not too old)
+  const maxAge = 5 * 60 * 1000 // 5 minutes
+  if (Date.now() - stored.storedAt > maxAge) {
+    clearStoredActiveStream()
+    return null
+  }
+
+  // Check stream status
+  const metadata = await checkStreamStatus(stored.streamId)
+  if (!metadata) {
+    clearStoredActiveStream()
+    return null
+  }
+
+  // Only resume if stream is still active
+  if (metadata.status !== 'streaming' && metadata.status !== 'pending') {
+    clearStoredActiveStream()
+    return null
+  }
+
+  // Get the stream
+  const stream = await resumeStream(stored.streamId, 0)
+  if (!stream) {
+    return null
+  }
+
+  logger.info('Stream resumption possible', {
+    streamId: stored.streamId,
+    status: metadata.status,
+  })
+
+  return { stream, metadata, offset: 0 }
+}
+
diff --git a/apps/sim/lib/copilot/stream-persistence.ts b/apps/sim/lib/copilot/stream-persistence.ts
new file mode 100644
index 000000000..f3ef70aa2
--- /dev/null
+++ b/apps/sim/lib/copilot/stream-persistence.ts
@@ -0,0 +1,327 @@
+import { createLogger } from '@sim/logger'
+import { getRedisClient } from '@/lib/core/config/redis'
+
+const logger = createLogger('StreamPersistence')
+
+const STREAM_PREFIX = 'copilot:stream:'
+const STREAM_TTL = 60 * 60 * 24 // 24 hours
+
+export type StreamStatus = 'pending' | 'streaming' | 'complete' | 'error' | 'aborted'
+
+export interface StreamMetadata {
+  streamId: string
+  chatId: string
+  userId: string
+  workflowId: string
+  userMessageId: string
+  assistantMessageId?: string
+  status: StreamStatus
+  isClientSession: boolean
+  createdAt: number
+  updatedAt: number
+  completedAt?: number
+  error?: string
+}
+
+export interface ToolCallState {
+  id: string
+  name: string
+  args: Record<string, unknown>
+  state: 'pending' | 'executing' | 'success' | 'error'
+  result?: unknown
+  error?: string
+}
+
+/**
+ * Initialize a new stream in Redis
+ */
+export async function createStream(params: {
+  streamId: string
+  chatId: string
+  userId: string
+  workflowId: string
+  userMessageId: string
+  isClientSession: boolean
+}): Promise<void> {
+  const redis = getRedisClient()
+  if (!redis) {
+    logger.warn('Redis not available, stream will not be resumable')
+    return
+  }
+
+  const metadata: StreamMetadata = {
+    ...params,
+    status: 'pending',
+    createdAt: Date.now(),
+    updatedAt: Date.now(),
+  }
+
+  const key = `${STREAM_PREFIX}${params.streamId}:meta`
+  await redis.set(key, JSON.stringify(metadata), 'EX', STREAM_TTL)
+
+  logger.info('Stream created', { streamId: params.streamId })
+}
+
+/**
+ * Update stream status
+ */
+export async function updateStreamStatus(
+  streamId: string,
+  status: StreamStatus,
+  error?: string
+): Promise<void> {
+  const redis = getRedisClient()
+  if (!redis) return
+
+  const key = `${STREAM_PREFIX}${streamId}:meta`
+  const data = await redis.get(key)
+  if (!data) return
+
+  const metadata: StreamMetadata = JSON.parse(data)
+  metadata.status = status
+  metadata.updatedAt = Date.now()
+  if (status === 'complete' || status === 'error') {
+    metadata.completedAt = Date.now()
+  }
+  if (error) {
+    metadata.error = error
+  }
+
+  await redis.set(key, JSON.stringify(metadata), 'EX', STREAM_TTL)
+}
+
+/**
+ * Update stream metadata with additional fields
+ */
+export async function updateStreamMetadata(
+  streamId: string,
+  updates: Partial<StreamMetadata>
+): Promise<void> {
+  const redis = getRedisClient()
+  if (!redis) return
+
+  const key = `${STREAM_PREFIX}${streamId}:meta`
+  const data = await redis.get(key)
+  if (!data) return
+
+  const metadata: StreamMetadata = JSON.parse(data)
+  Object.assign(metadata, updates, { updatedAt: Date.now() })
+
+  await redis.set(key, JSON.stringify(metadata), 'EX', STREAM_TTL)
+}
+
+/**
+ * Append a serialized SSE event chunk to the stream
+ */
+export async function appendChunk(streamId: string, chunk: string): Promise<void> {
+  const redis = getRedisClient()
+  if (!redis) return
+
+  const key = `${STREAM_PREFIX}${streamId}:events`
+  await redis.rpush(key, chunk)
+  await redis.expire(key, STREAM_TTL)
+}
+
+/**
+ * Append text content (for quick content retrieval without parsing events)
+ */
+export async function appendContent(streamId: string, content: string): Promise<void> {
+  const redis = getRedisClient()
+  if (!redis) return
+
+  const key = `${STREAM_PREFIX}${streamId}:content`
+  await redis.append(key, content)
+  await redis.expire(key, STREAM_TTL)
+}
+
+/**
+ * Update tool call state
+ */
+export async function updateToolCall(
+  streamId: string,
+  toolCallId: string,
+  update: Partial<ToolCallState>
+): Promise<void> {
+  const redis = getRedisClient()
+  if (!redis) return
+
+  const key = `${STREAM_PREFIX}${streamId}:tools`
+  const existing = await redis.hget(key, toolCallId)
+  const current: ToolCallState = existing
+    ? JSON.parse(existing)
+    : { id: toolCallId, name: '', args: {}, state: 'pending' }
+
+  const updated = { ...current, ...update }
+  await redis.hset(key, toolCallId, JSON.stringify(updated))
+  await redis.expire(key, STREAM_TTL)
+}
+
+/**
+ * Mark stream as complete
+ */
+export async function completeStream(streamId: string, result?: unknown): Promise<void> {
+  const redis = getRedisClient()
+  if (!redis) return
+
+  await updateStreamStatus(streamId, 'complete')
+
+  if (result !== undefined) {
+    const key = `${STREAM_PREFIX}${streamId}:result`
+    await redis.set(key, JSON.stringify(result), 'EX', STREAM_TTL)
+  }
+
+  logger.info('Stream completed', { streamId })
+}
+
+/**
+ * Mark stream as errored
+ */
+export async function errorStream(streamId: string, error: string): Promise<void> {
+  await updateStreamStatus(streamId, 'error', error)
+  logger.error('Stream errored', { streamId, error })
+}
+
+/**
+ * Check if stream was aborted (client requested abort)
+ */
+export async function checkAbortSignal(streamId: string): Promise<boolean> {
+  const redis = getRedisClient()
+  if (!redis) return false
+
+  const key = `${STREAM_PREFIX}${streamId}:abort`
+  const aborted = await redis.exists(key)
+  return aborted === 1
+}
+
+/**
+ * Signal stream abort
+ */
+export async function abortStream(streamId: string): Promise<void> {
+  const redis = getRedisClient()
+  if (!redis) return
+
+  await redis.set(`${STREAM_PREFIX}${streamId}:abort`, '1', 'EX', STREAM_TTL)
+  await updateStreamStatus(streamId, 'aborted')
+  logger.info('Stream aborted', { streamId })
+}
+
+/**
+ * Refresh TTL on all stream keys
+ */
+export async function refreshStreamTTL(streamId: string): Promise<void> {
+  const redis = getRedisClient()
+  if (!redis) return
+
+  const keys = [
+    `${STREAM_PREFIX}${streamId}:meta`,
+    `${STREAM_PREFIX}${streamId}:events`,
+    `${STREAM_PREFIX}${streamId}:content`,
+    `${STREAM_PREFIX}${streamId}:tools`,
+    `${STREAM_PREFIX}${streamId}:result`,
+  ]
+
+  for (const key of keys) {
+    await redis.expire(key, STREAM_TTL)
+  }
+}
+
+/**
+ * Get stream metadata
+ */
+export async function getStreamMetadata(streamId: string): Promise<StreamMetadata | null> {
+  const redis = getRedisClient()
+  if (!redis) return null
+
+  const data = await redis.get(`${STREAM_PREFIX}${streamId}:meta`)
+  return data ? JSON.parse(data) : null
+}
+
+/**
+ * Get stream events from offset (for resumption)
+ */
+export async function getStreamEvents(streamId: string, fromOffset: number = 0): Promise<string[]> {
+  const redis = getRedisClient()
+  if (!redis) return []
+
+  const key = `${STREAM_PREFIX}${streamId}:events`
+  return redis.lrange(key, fromOffset, -1)
+}
+
+/**
+ * Get current event count (for client to know where it is)
+ */
+export async function getStreamEventCount(streamId: string): Promise<number> {
+  const redis = getRedisClient()
+  if (!redis) return 0
+
+  const key = `${STREAM_PREFIX}${streamId}:events`
+  return redis.llen(key)
+}
+
+/**
+ * Get all tool call states
+ */
+export async function getToolCallStates(streamId: string): Promise<Record<string, ToolCallState>> {
+  const redis = getRedisClient()
+  if (!redis) return {}
+
+  const key = `${STREAM_PREFIX}${streamId}:tools`
+  const data = await redis.hgetall(key)
+
+  const result: Record<string, ToolCallState> = {}
+  for (const [id, json] of Object.entries(data)) {
+    result[id] = JSON.parse(json)
+  }
+  return result
+}
+
+/**
+ * Get accumulated content
+ */
+export async function getStreamContent(streamId: string): Promise<string> {
+  const redis = getRedisClient()
+  if (!redis) return ''
+
+  const key = `${STREAM_PREFIX}${streamId}:content`
+  return (await redis.get(key)) || ''
+}
+
+/**
+ * Get final result (if complete)
+ */
+export async function getStreamResult(streamId: string): Promise<unknown | null> {
+  const redis = getRedisClient()
+  if (!redis) return null
+
+  const key = `${STREAM_PREFIX}${streamId}:result`
+  const data = await redis.get(key)
+  return data ? JSON.parse(data) : null
+}
+
+/**
+ * Check if Redis is available for stream persistence
+ */
+export function isStreamPersistenceEnabled(): boolean {
+  return getRedisClient() !== null
+}
+
+/**
+ * Delete all stream data (cleanup)
+ */
+export async function deleteStream(streamId: string): Promise<void> {
+  const redis = getRedisClient()
+  if (!redis) return
+
+  const keys = [
+    `${STREAM_PREFIX}${streamId}:meta`,
+    `${STREAM_PREFIX}${streamId}:events`,
+    `${STREAM_PREFIX}${streamId}:content`,
+    `${STREAM_PREFIX}${streamId}:tools`,
+    `${STREAM_PREFIX}${streamId}:result`,
+    `${STREAM_PREFIX}${streamId}:abort`,
+  ]
+
+  await redis.del(...keys)
+  logger.info('Stream deleted', { streamId })
+}
+
diff --git a/apps/sim/lib/copilot/stream-transformer.ts b/apps/sim/lib/copilot/stream-transformer.ts
new file mode 100644
index 000000000..8b6e20358
--- /dev/null
+++ b/apps/sim/lib/copilot/stream-transformer.ts
@@ -0,0 +1,419 @@
+import { createLogger } from '@sim/logger'
+import type { RenderEvent } from './render-events'
+
+const logger = createLogger('StreamTransformer')
+
+export interface TransformStreamContext {
+  streamId: string
+  chatId: string
+  userId: string
+  workflowId: string
+  userMessageId: string
+  assistantMessageId: string
+
+  /** Callback for each render event - handles both client delivery and persistence */
+  onRenderEvent: (event: RenderEvent) => Promise<void>
+
+  /** Callback for persistence operations */
+  onPersist?: (data: { type: string; [key: string]: unknown }) => Promise<void>
+
+  /** Check if stream should be aborted */
+  isAborted: () => boolean | Promise<boolean>
+}
+
+interface SimAgentEvent {
+  type?: string
+  event?: string
+  data?: unknown
+  [key: string]: unknown
+}
+
+/**
+ * Transform a sim agent SSE stream into normalized render events.
+ * This function consumes the entire stream and emits events via callbacks.
+ */
+export async function transformStream(
+  body: ReadableStream<Uint8Array>,
+  context: TransformStreamContext
+): Promise<void> {
+  const { onRenderEvent, onPersist, isAborted } = context
+
+  const reader = body.getReader()
+  const decoder = new TextDecoder()
+  let buffer = ''
+
+  try {
+    while (true) {
+      // Check abort signal
+      const shouldAbort = await Promise.resolve(isAborted())
+      if (shouldAbort) {
+        logger.info('Stream aborted by signal', { streamId: context.streamId })
+        break
+      }
+
+      const { done, value } = await reader.read()
+      if (done) break
+
+      buffer += decoder.decode(value, { stream: true })
+
+      // Process complete SSE messages (separated by double newlines)
+      const messages = buffer.split('\n\n')
+      buffer = messages.pop() || '' // Keep incomplete message in buffer
+
+      for (const message of messages) {
+        if (!message.trim()) continue
+
+        const events = parseSimAgentMessage(message)
+        for (const simEvent of events) {
+          const renderEvents = transformSimAgentEvent(simEvent, context)
+          for (const renderEvent of renderEvents) {
+            await onRenderEvent(renderEvent)
+          }
+        }
+      }
+    }
+
+    // Process any remaining buffer content
+    if (buffer.trim()) {
+      const events = parseSimAgentMessage(buffer)
+      for (const simEvent of events) {
+        const renderEvents = transformSimAgentEvent(simEvent, context)
+        for (const renderEvent of renderEvents) {
+          await onRenderEvent(renderEvent)
+        }
+      }
+    }
+
+    // Emit message complete
+    await onRenderEvent({
+      type: 'message_complete',
+      messageId: context.assistantMessageId,
+      timestamp: Date.now(),
+    })
+
+    // Notify persistence layer
+    if (onPersist) {
+      await onPersist({ type: 'message_complete', messageId: context.assistantMessageId })
+    }
+  } catch (error) {
+    logger.error('Stream transform error', { streamId: context.streamId, error })
+
+    await onRenderEvent({
+      type: 'error',
+      error: error instanceof Error ? error.message : 'Stream processing error',
+      timestamp: Date.now(),
+    })
+
+    throw error
+  } finally {
+    reader.releaseLock()
+  }
+}
+
+/**
+ * Parse a raw SSE message into sim agent events
+ */
+function parseSimAgentMessage(message: string): SimAgentEvent[] {
+  const events: SimAgentEvent[] = []
+  const lines = message.split('\n')
+
+  let currentEvent: string | null = null
+  let currentData: string[] = []
+
+  for (const line of lines) {
+    if (line.startsWith('event: ')) {
+      // If we have accumulated data, emit previous event
+      if (currentData.length > 0) {
+        const dataStr = currentData.join('\n')
+        const parsed = tryParseJson(dataStr)
+        if (parsed) {
+          events.push({ ...parsed, event: currentEvent || undefined })
+        }
+        currentData = []
+      }
+      currentEvent = line.slice(7)
+    } else if (line.startsWith('data: ')) {
+      currentData.push(line.slice(6))
+    } else if (line === '' && currentData.length > 0) {
+      // Empty line signals end of event
+      const dataStr = currentData.join('\n')
+      const parsed = tryParseJson(dataStr)
+      if (parsed) {
+        events.push({ ...parsed, event: currentEvent || undefined })
+      }
+      currentEvent = null
+      currentData = []
+    }
+  }
+
+  // Handle remaining data
+  if (currentData.length > 0) {
+    const dataStr = currentData.join('\n')
+    const parsed = tryParseJson(dataStr)
+    if (parsed) {
+      events.push({ ...parsed, event: currentEvent || undefined })
+    }
+  }
+
+  return events
+}
+
+function tryParseJson(str: string): Record<string, unknown> | null {
+  if (str === '[DONE]') return null
+  try {
+    return JSON.parse(str)
+  } catch {
+    return null
+  }
+}
+
+/**
+ * Transform a sim agent event into one or more render events
+ */
+function transformSimAgentEvent(
+  simEvent: SimAgentEvent,
+  context: TransformStreamContext
+): RenderEvent[] {
+  const eventType = simEvent.type || simEvent.event
+  const events: RenderEvent[] = []
+  const timestamp = Date.now()
+
+  switch (eventType) {
+    // Text content events
+    case 'content_block_delta':
+    case 'text_delta':
+    case 'delta': {
+      const delta = (simEvent.delta as Record<string, unknown>) || simEvent
+      const text = (delta.text as string) || (delta.content as string) || (simEvent.text as string)
+      if (text) {
+        events.push({ type: 'text_delta', content: text, timestamp })
+      }
+      break
+    }
+
+    case 'content_block_stop':
+    case 'text_complete': {
+      events.push({
+        type: 'text_complete',
+        content: (simEvent.content as string) || '',
+        timestamp,
+      })
+      break
+    }
+
+    // Tool call events
+    case 'tool_call':
+    case 'tool_use': {
+      const data = (simEvent.data as Record<string, unknown>) || simEvent
+      const toolCallId = (data.id as string) || (simEvent.id as string)
+      const toolName = (data.name as string) || (simEvent.name as string)
+      const args = (data.arguments as Record<string, unknown>) || (data.input as Record<string, unknown>)
+
+      if (toolCallId && toolName) {
+        events.push({
+          type: 'tool_pending',
+          toolCallId,
+          toolName,
+          args,
+          timestamp,
+        })
+      }
+      break
+    }
+
+    case 'tool_executing': {
+      const toolCallId = (simEvent.toolCallId as string) || (simEvent.id as string)
+      const toolName = (simEvent.toolName as string) || (simEvent.name as string) || ''
+
+      if (toolCallId) {
+        events.push({
+          type: 'tool_executing',
+          toolCallId,
+          toolName,
+          timestamp,
+        })
+      }
+      break
+    }
+
+    case 'tool_result': {
+      const toolCallId = (simEvent.toolCallId as string) || (simEvent.id as string)
+      const success = simEvent.success as boolean
+      const result = simEvent.result
+      const error = simEvent.error as string | undefined
+
+      if (toolCallId) {
+        events.push({
+          type: 'tool_result',
+          toolCallId,
+          success: success !== false,
+          result,
+          error,
+          failedDependency: simEvent.failedDependency as boolean | undefined,
+          skipped: (simEvent.result as Record<string, unknown>)?.skipped as boolean | undefined,
+          timestamp,
+        })
+
+        // Also emit success/error event for UI
+        if (success !== false) {
+          events.push({
+            type: 'tool_success',
+            toolCallId,
+            toolName: (simEvent.toolName as string) || '',
+            result,
+            timestamp,
+          })
+        } else {
+          events.push({
+            type: 'tool_error',
+            toolCallId,
+            toolName: (simEvent.toolName as string) || '',
+            error: error || 'Tool execution failed',
+            timestamp,
+          })
+        }
+      }
+      break
+    }
+
+    // Subagent events
+    case 'subagent_start': {
+      events.push({
+        type: 'subagent_start',
+        parentToolCallId: simEvent.parentToolCallId as string,
+        subagentName: simEvent.subagentName as string,
+        timestamp,
+      })
+      break
+    }
+
+    case 'subagent_text':
+    case 'subagent_delta': {
+      events.push({
+        type: 'subagent_text',
+        parentToolCallId: simEvent.parentToolCallId as string,
+        content: (simEvent.content as string) || (simEvent.text as string) || '',
+        timestamp,
+      })
+      break
+    }
+
+    case 'subagent_tool_call': {
+      events.push({
+        type: 'subagent_tool_call',
+        parentToolCallId: simEvent.parentToolCallId as string,
+        toolCallId: simEvent.toolCallId as string,
+        toolName: simEvent.toolName as string,
+        args: simEvent.args as Record<string, unknown> | undefined,
+        state: (simEvent.state as 'pending' | 'executing' | 'success' | 'error') || 'pending',
+        result: simEvent.result,
+        error: simEvent.error as string | undefined,
+        timestamp,
+      })
+      break
+    }
+
+    case 'subagent_end': {
+      events.push({
+        type: 'subagent_end',
+        parentToolCallId: simEvent.parentToolCallId as string,
+        timestamp,
+      })
+      break
+    }
+
+    // Thinking events (for extended thinking models)
+    case 'thinking_start':
+    case 'thinking': {
+      if (simEvent.type === 'thinking_start' || !simEvent.content) {
+        events.push({ type: 'thinking_start', timestamp })
+      }
+      if (simEvent.content) {
+        events.push({
+          type: 'thinking_delta',
+          content: simEvent.content as string,
+          timestamp,
+        })
+      }
+      break
+    }
+
+    case 'thinking_delta': {
+      events.push({
+        type: 'thinking_delta',
+        content: (simEvent.content as string) || '',
+        timestamp,
+      })
+      break
+    }
+
+    case 'thinking_end':
+    case 'thinking_complete': {
+      events.push({ type: 'thinking_end', timestamp })
+      break
+    }
+
+    // Message lifecycle events
+    case 'message_start': {
+      events.push({
+        type: 'message_start',
+        messageId: (simEvent.messageId as string) || context.assistantMessageId,
+        timestamp,
+      })
+      break
+    }
+
+    case 'message_stop':
+    case 'message_complete':
+    case 'message_delta': {
+      if (eventType === 'message_complete' || eventType === 'message_stop') {
+        events.push({
+          type: 'message_complete',
+          messageId: (simEvent.messageId as string) || context.assistantMessageId,
+          content: simEvent.content as string | undefined,
+          timestamp,
+        })
+      }
+      break
+    }
+
+    // Metadata events
+    case 'chat_id': {
+      events.push({
+        type: 'chat_id',
+        chatId: simEvent.chatId as string,
+        timestamp,
+      })
+      break
+    }
+
+    case 'conversation_id': {
+      events.push({
+        type: 'conversation_id',
+        conversationId: simEvent.conversationId as string,
+        timestamp,
+      })
+      break
+    }
+
+    // Error events
+    case 'error': {
+      events.push({
+        type: 'error',
+        error: (simEvent.error as string) || (simEvent.message as string) || 'Unknown error',
+        code: simEvent.code as string | undefined,
+        timestamp,
+      })
+      break
+    }
+
+    default: {
+      // Log unhandled event types for debugging
+      if (eventType && eventType !== 'ping') {
+        logger.debug('Unhandled sim agent event type', { eventType, streamId: context.streamId })
+      }
+    }
+  }
+
+  return events
+}
diff --git a/apps/sim/lib/copilot/tools/server/executor.ts b/apps/sim/lib/copilot/tools/server/executor.ts
new file mode 100644
index 000000000..77277adfa
--- /dev/null
+++ b/apps/sim/lib/copilot/tools/server/executor.ts
@@ -0,0 +1,255 @@
+import { createLogger } from '@sim/logger'
+import { routeExecution } from './router'
+import { saveWorkflowToNormalizedTables } from '@/lib/workflows/persistence/utils'
+
+const logger = createLogger('ServerToolExecutor')
+
+export interface ServerToolContext {
+  workflowId: string
+  userId: string
+  persistChanges?: boolean
+}
+
+export interface ServerToolResult {
+  success: boolean
+  result?: unknown
+  error?: string
+}
+
+/**
+ * Execute any copilot tool completely server-side.
+ * This is the central dispatcher for headless/API operation.
+ */
+export async function executeToolServerSide(
+  toolCall: { name: string; args: Record<string, unknown> },
+  context: ServerToolContext
+): Promise<ServerToolResult> {
+  const { name, args } = toolCall
+  const { workflowId, userId, persistChanges = true } = context
+
+  logger.info('Executing tool server-side', { name, workflowId, userId })
+
+  try {
+    const result = await executeToolInternal(name, args, context)
+    return { success: true, result }
+  } catch (error) {
+    logger.error('Server-side tool execution failed', {
+      name,
+      workflowId,
+      error: error instanceof Error ? error.message : String(error),
+    })
+    return {
+      success: false,
+      error: error instanceof Error ? error.message : 'Tool execution failed',
+    }
+  }
+}
+
+async function executeToolInternal(
+  name: string,
+  args: Record<string, unknown>,
+  context: ServerToolContext
+): Promise<unknown> {
+  const { workflowId, userId, persistChanges = true } = context
+
+  switch (name) {
+    case 'edit_workflow': {
+      // Execute edit_workflow with direct persistence
+      const result = await routeExecution(
+        'edit_workflow',
+        {
+          ...args,
+          workflowId,
+          // Don't require currentUserWorkflow - server tool will load from DB
+        },
+        { userId }
+      )
+
+      // Persist directly to database if enabled
+      if (persistChanges && result.workflowState) {
+        try {
+          await saveWorkflowToNormalizedTables(workflowId, result.workflowState)
+          logger.info('Workflow changes persisted directly', { workflowId })
+        } catch (error) {
+          logger.error('Failed to persist workflow changes', { error, workflowId })
+          // Don't throw - return the result anyway
+        }
+      }
+
+      return result
+    }
+
+    case 'run_workflow': {
+      // Import dynamically to avoid circular dependencies
+      const { executeWorkflow } = await import('@/lib/workflows/executor/execute-workflow')
+
+      const result = await executeWorkflow({
+        workflowId,
+        input: (args.workflow_input as Record<string, unknown>) || {},
+        isClientSession: false,
+      })
+
+      return result
+    }
+
+    case 'deploy_api':
+    case 'deploy_chat':
+    case 'deploy_mcp': {
+      // Import dynamically
+      const { deployWorkflow } = await import('@/lib/workflows/persistence/utils')
+
+      const deployType = name.replace('deploy_', '')
+      const result = await deployWorkflow({
+        workflowId,
+        deployedBy: userId,
+      })
+
+      return { ...result, deployType }
+    }
+
+    case 'redeploy': {
+      const { deployWorkflow } = await import('@/lib/workflows/persistence/utils')
+
+      const result = await deployWorkflow({
+        workflowId,
+        deployedBy: userId,
+      })
+
+      return result
+    }
+
+    // Server tools that already exist in the router
+    case 'get_blocks_and_tools':
+    case 'get_blocks_metadata':
+    case 'get_block_options':
+    case 'get_block_config':
+    case 'get_trigger_blocks':
+    case 'get_workflow_console':
+    case 'search_documentation':
+    case 'search_online':
+    case 'set_environment_variables':
+    case 'get_credentials':
+    case 'make_api_request':
+    case 'knowledge_base': {
+      return routeExecution(name, args, { userId })
+    }
+
+    // Tools that just need workflowId context
+    case 'get_user_workflow':
+    case 'get_workflow_data': {
+      const { loadWorkflowFromNormalizedTables } = await import(
+        '@/lib/workflows/persistence/utils'
+      )
+      const { sanitizeForCopilot } = await import('@/lib/workflows/sanitization/json-sanitizer')
+
+      const workflowData = await loadWorkflowFromNormalizedTables(workflowId)
+      if (!workflowData) {
+        throw new Error('Workflow not found')
+      }
+
+      const sanitized = sanitizeForCopilot({
+        blocks: workflowData.blocks,
+        edges: workflowData.edges,
+        loops: workflowData.loops,
+        parallels: workflowData.parallels,
+      })
+
+      return { workflow: JSON.stringify(sanitized, null, 2) }
+    }
+
+    case 'list_user_workflows': {
+      const { db } = await import('@sim/db')
+      const { workflow: workflowTable } = await import('@sim/db/schema')
+      const { eq } = await import('drizzle-orm')
+
+      const workflows = await db
+        .select({
+          id: workflowTable.id,
+          name: workflowTable.name,
+          description: workflowTable.description,
+          isDeployed: workflowTable.isDeployed,
+          createdAt: workflowTable.createdAt,
+          updatedAt: workflowTable.updatedAt,
+        })
+        .from(workflowTable)
+        .where(eq(workflowTable.userId, userId))
+
+      return { workflows }
+    }
+
+    case 'check_deployment_status': {
+      const { db } = await import('@sim/db')
+      const { workflow: workflowTable } = await import('@sim/db/schema')
+      const { eq } = await import('drizzle-orm')
+
+      const [wf] = await db
+        .select({
+          isDeployed: workflowTable.isDeployed,
+          deployedAt: workflowTable.deployedAt,
+        })
+        .from(workflowTable)
+        .where(eq(workflowTable.id, workflowId))
+        .limit(1)
+
+      return {
+        isDeployed: wf?.isDeployed || false,
+        deployedAt: wf?.deployedAt || null,
+      }
+    }
+
+    default: {
+      logger.warn('Unknown tool for server-side execution', { name })
+      throw new Error(`Tool ${name} is not available for server-side execution`)
+    }
+  }
+}
+
+/**
+ * Check if a tool can be executed server-side
+ */
+export function isServerExecutableTool(toolName: string): boolean {
+  const serverExecutableTools = new Set([
+    // Core editing tools
+    'edit_workflow',
+    'run_workflow',
+
+    // Deployment tools
+    'deploy_api',
+    'deploy_chat',
+    'deploy_mcp',
+    'redeploy',
+    'check_deployment_status',
+
+    // Existing server tools
+    'get_blocks_and_tools',
+    'get_blocks_metadata',
+    'get_block_options',
+    'get_block_config',
+    'get_trigger_blocks',
+    'get_workflow_console',
+    'search_documentation',
+    'search_online',
+    'set_environment_variables',
+    'get_credentials',
+    'make_api_request',
+    'knowledge_base',
+
+    // Workflow info tools
+    'get_user_workflow',
+    'get_workflow_data',
+    'list_user_workflows',
+  ])
+
+  return serverExecutableTools.has(toolName)
+}
+
+/**
+ * Get list of tools that require client-side execution
+ */
+export function getClientOnlyTools(): string[] {
+  return [
+    'navigate_ui', // Requires DOM
+    'oauth_request_access', // Requires browser auth flow
+  ]
+}
+
diff --git a/apps/sim/stores/panel/copilot/store.ts b/apps/sim/stores/panel/copilot/store.ts
index 697265df8..aa4f10cbf 100644
--- a/apps/sim/stores/panel/copilot/store.ts
+++ b/apps/sim/stores/panel/copilot/store.ts
@@ -2708,6 +2708,16 @@ export const useCopilotStore = create<CopilotStore>()(
         })
 
         if (result.success && result.stream) {
+          // Store stream ID for potential resumption on disconnect
+          if (result.streamId) {
+            const { storeActiveStream } = await import('@/lib/copilot/stream-client')
+            storeActiveStream(
+              result.chatId || currentChat?.id || '',
+              result.streamId,
+              streamingMessage.id
+            )
+          }
+
           await get().handleStreamingResponse(
             result.stream,
             streamingMessage.id,
@@ -2715,6 +2725,12 @@ export const useCopilotStore = create<CopilotStore>()(
             userMessage.id
           )
           set({ chatsLastLoadedAt: null, chatsLoadedForWorkflow: null })
+
+          // Clear stream storage on successful completion
+          if (result.streamId) {
+            const { clearStoredActiveStream } = await import('@/lib/copilot/stream-client')
+            clearStoredActiveStream()
+          }
         } else {
           if (result.error === 'Request was aborted') {
             return
@@ -3853,6 +3869,68 @@ export const useCopilotStore = create<CopilotStore>()(
       return autoAllowedTools.includes(toolId)
     },
 
+    // Stream resumption
+    attemptStreamResumption: async () => {
+      const { isSendingMessage } = get()
+      if (isSendingMessage) {
+        logger.info('[Stream] Cannot attempt resumption while already sending')
+        return false
+      }
+
+      try {
+        const { attemptStreamResumption, clearStoredActiveStream } = await import(
+          '@/lib/copilot/stream-client'
+        )
+
+        const resumption = await attemptStreamResumption()
+        if (!resumption) {
+          return false
+        }
+
+        const { stream, metadata } = resumption
+
+        logger.info('[Stream] Resuming stream', {
+          streamId: metadata.streamId,
+          chatId: metadata.chatId,
+        })
+
+        // Find or create the assistant message for this stream
+        const { messages } = get()
+        let assistantMessageId = metadata.assistantMessageId
+
+        // If we don't have the assistant message, create a placeholder
+        if (!assistantMessageId || !messages.find((m) => m.id === assistantMessageId)) {
+          assistantMessageId = crypto.randomUUID()
+          const streamingMessage: CopilotMessage = {
+            id: assistantMessageId,
+            role: 'assistant',
+            content: '',
+            timestamp: new Date().toISOString(),
+            isStreaming: true,
+            contentBlocks: [],
+          }
+          set((state) => ({
+            messages: [...state.messages, streamingMessage],
+            isSendingMessage: true,
+          }))
+        }
+
+        // Process the resumed stream
+        await get().handleStreamingResponse(
+          stream,
+          assistantMessageId,
+          true, // This is a continuation
+          metadata.userMessageId
+        )
+
+        clearStoredActiveStream()
+        return true
+      } catch (error) {
+        logger.error('[Stream] Resumption failed', { error })
+        return false
+      }
+    },
+
     // Message queue actions
     addToQueue: (message, options) => {
       const queuedMessage: import('./types').QueuedMessage = {
diff --git a/apps/sim/stores/panel/copilot/types.ts b/apps/sim/stores/panel/copilot/types.ts
index 477275c3a..29c244cc2 100644
--- a/apps/sim/stores/panel/copilot/types.ts
+++ b/apps/sim/stores/panel/copilot/types.ts
@@ -63,6 +63,8 @@ export interface CopilotMessage {
   fileAttachments?: MessageFileAttachment[]
   contexts?: ChatContext[]
   errorType?: 'usage_limit' | 'unauthorized' | 'forbidden' | 'rate_limit' | 'upgrade_required'
+  /** Whether this message is currently being streamed */
+  isStreaming?: boolean
 }
 
 /**
@@ -235,6 +237,9 @@ export interface CopilotActions {
   removeAutoAllowedTool: (toolId: string) => Promise<void>
   isToolAutoAllowed: (toolId: string) => boolean
 
+  // Stream resumption
+  attemptStreamResumption: () => Promise<boolean>
+
   // Message queue actions
   addToQueue: (
     message: string,