feat(vfs): add lazy vfs + remove dynamic fields for prompt caching hits

apps/sim/lib/copilot/chat/payload.ts

@@ -3,6 +3,7 @@ import { toError } from '@sim/utils/errors'
 import { LRUCache } from 'lru-cache'
 import { getHighestPrioritySubscription } from '@/lib/billing/core/subscription'
 import { isPaid } from '@/lib/billing/plan-helpers'
+import type { VfsSnapshotV1 } from '@/lib/copilot/generated/vfs-snapshot-v1'
 import { getExposedIntegrationTools } from '@/lib/copilot/integration-tools'
 import { getToolEntry } from '@/lib/copilot/tool-executor/router'
 import { getCopilotToolDescription } from '@/lib/copilot/tools/descriptions'
@@ -33,6 +34,7 @@ interface BuildPayloadParams {
   prefetch?: boolean
   implicitFeedback?: string
   workspaceContext?: string
+  vfs?: VfsSnapshotV1
   userPermission?: string
   userTimezone?: string
   userMetadata?: {
@@ -366,6 +368,7 @@ export async function buildCopilotRequestPayload(
     ...(mothershipTools.length > 0 ? { mothershipTools } : {}),
     ...(commands && commands.length > 0 ? { commands } : {}),
     ...(params.workspaceContext ? { workspaceContext: params.workspaceContext } : {}),
+    ...(params.vfs ? { vfs: params.vfs } : {}),
     ...(params.userPermission ? { userPermission: params.userPermission } : {}),
     ...(params.userTimezone ? { userTimezone: params.userTimezone } : {}),
     ...(params.userMetadata &&

apps/sim/lib/copilot/chat/post.test.ts

@@ -17,7 +17,7 @@ const getUserEntityPermissions = permissionsMockFns.mockGetUserEntityPermissions
 
 const {
   getEffectiveDecryptedEnv,
-  generateWorkspaceContext,
+  generateWorkspaceSnapshot,
   processContextsServer,
   resolveActiveResourceContext,
   buildCopilotRequestPayload,
@@ -31,7 +31,7 @@ const {
   mockPublishStatusChanged,
 } = vi.hoisted(() => ({
   getEffectiveDecryptedEnv: vi.fn(),
-  generateWorkspaceContext: vi.fn(),
+  generateWorkspaceSnapshot: vi.fn(),
   processContextsServer: vi.fn(),
   resolveActiveResourceContext: vi.fn(),
   buildCopilotRequestPayload: vi.fn(),
@@ -56,7 +56,7 @@ vi.mock('@/lib/environment/utils', () => ({
 }))
 
 vi.mock('@/lib/copilot/chat/workspace-context', () => ({
-  generateWorkspaceContext,
+  generateWorkspaceSnapshot,
 }))
 
 vi.mock('@/lib/copilot/chat/process-contents', () => ({
@@ -142,7 +142,10 @@ describe('handleUnifiedChatPost', () => {
     })
     getUserEntityPermissions.mockResolvedValue('write')
     getEffectiveDecryptedEnv.mockResolvedValue({ API_KEY: 'secret' })
-    generateWorkspaceContext.mockResolvedValue('workspace context')
+    generateWorkspaceSnapshot.mockResolvedValue({
+      markdown: 'workspace context',
+      snapshot: { workflows: [{ id: 'wf-1', name: 'Alpha', path: 'workflows/Alpha' }] },
+    })
     processContextsServer.mockResolvedValue([])
     resolveActiveResourceContext.mockResolvedValue(null)
     buildCopilotRequestPayload.mockImplementation(async (params: Record<string, unknown>) => params)
@@ -178,11 +181,13 @@ describe('handleUnifiedChatPost', () => {
     )
 
     expect(response.status).toBe(200)
-    expect(generateWorkspaceContext).toHaveBeenCalledWith('ws-1', 'user-1')
+    expect(generateWorkspaceSnapshot).toHaveBeenCalledWith('ws-1', 'user-1')
     expect(buildCopilotRequestPayload).toHaveBeenCalledWith(
       expect.objectContaining({
         model: 'claude-opus-4-8',
         workspaceContext: 'workspace context',
+        // Regression guard: the branch must forward the typed snapshot, not drop it.
+        vfs: expect.objectContaining({ workflows: expect.any(Array) }),
       }),
       { selectedModel: 'claude-opus-4-8' }
     )
@@ -221,6 +226,8 @@ describe('handleUnifiedChatPost', () => {
       expect.objectContaining({
         workspaceId: 'ws-1',
         workspaceContext: 'workspace context',
+        // Regression guard: the branch must forward the typed snapshot, not drop it.
+        vfs: expect.objectContaining({ workflows: expect.any(Array) }),
       }),
       { selectedModel: '' }
     )

apps/sim/lib/copilot/chat/post.ts

@@ -22,7 +22,7 @@ import {
   resolveActiveResourceContext,
 } from '@/lib/copilot/chat/process-contents'
 import { finalizeAssistantTurn } from '@/lib/copilot/chat/terminal-state'
-import { generateWorkspaceContext } from '@/lib/copilot/chat/workspace-context'
+import { generateWorkspaceSnapshot } from '@/lib/copilot/chat/workspace-context'
 import { chatPubSub } from '@/lib/copilot/chat-status'
 import { COPILOT_REQUEST_MODES } from '@/lib/copilot/constants'
 import {
@@ -32,6 +32,7 @@ import {
 } from '@/lib/copilot/generated/trace-attribute-values-v1'
 import { TraceAttr } from '@/lib/copilot/generated/trace-attributes-v1'
 import { TraceSpan } from '@/lib/copilot/generated/trace-spans-v1'
+import type { VfsSnapshotV1 } from '@/lib/copilot/generated/vfs-snapshot-v1'
 import { createBadRequestResponse, createUnauthorizedResponse } from '@/lib/copilot/request/http'
 import { createSSEStream, SSE_RESPONSE_HEADERS } from '@/lib/copilot/request/lifecycle/start'
 import { startCopilotOtelRoot, withCopilotSpan } from '@/lib/copilot/request/otel'
@@ -183,6 +184,7 @@ type UnifiedChatBranch =
         prefetch?: boolean
         implicitFeedback?: string
         workspaceContext?: string
+        vfs?: VfsSnapshotV1
       }) => Promise<Record<string, unknown>>
       buildExecutionContext: (params: {
         userId: string
@@ -210,6 +212,7 @@ type UnifiedChatBranch =
         userTimezone?: string
         userMetadata?: { name?: string; email?: string; timezone?: string }
         workspaceContext?: string
+        vfs?: VfsSnapshotV1
       }) => Promise<Record<string, unknown>>
       buildExecutionContext: (params: {
         userId: string
@@ -616,6 +619,7 @@ async function resolveBranch(params: {
             prefetch: payloadParams.prefetch,
             implicitFeedback: payloadParams.implicitFeedback,
             workspaceContext: payloadParams.workspaceContext,
+            vfs: payloadParams.vfs,
             userPermission: payloadParams.userPermission,
             userTimezone: payloadParams.userTimezone,
             userMetadata: payloadParams.userMetadata,
@@ -675,6 +679,7 @@ async function resolveBranch(params: {
           fileAttachments: payloadParams.fileAttachments,
           chatId: payloadParams.chatId,
           workspaceContext: payloadParams.workspaceContext,
+          vfs: payloadParams.vfs,
           userPermission: payloadParams.userPermission,
           userTimezone: payloadParams.userTimezone,
           userMetadata: payloadParams.userMetadata,
@@ -898,7 +903,7 @@ export async function handleUnifiedChatPost(req: NextRequest) {
         ? withCopilotSpan(
             TraceSpan.CopilotChatBuildWorkspaceContext,
             { [TraceAttr.WorkspaceId]: workspaceId },
-            () => generateWorkspaceContext(workspaceId, authenticatedUserId),
+            () => generateWorkspaceSnapshot(workspaceId, authenticatedUserId),
             activeOtelRoot.context
           )
         : Promise.resolve(undefined)
@@ -943,14 +948,19 @@ export async function handleUnifiedChatPost(req: NextRequest) {
         activeOtelRoot.context
       )
 
-      const [agentContexts, userPermission, workspaceContext, , executionContext] =
+      const [agentContexts, userPermission, workspaceSnapshot, , executionContext] =
         await Promise.all([
           agentContextsPromise,
           userPermissionPromise,
           workspaceContextPromise,
           persistUserMessagePromise,
           executionContextPromise,
         ])
+      // Both halves come from one primary-db fetch (workspace-context.ts):
+      // `workspaceContext` is the markdown transition fallback, `vfs` is the
+      // typed snapshot Go diffs into baseline+delta messages.
+      const workspaceContext = workspaceSnapshot?.markdown
+      const vfs = workspaceSnapshot?.snapshot
 
       executionContext.userPermission = userPermission ?? undefined
 
@@ -987,6 +997,7 @@ export async function handleUnifiedChatPost(req: NextRequest) {
                 prefetch: body.prefetch,
                 implicitFeedback: body.implicitFeedback,
                 workspaceContext,
+                vfs,
               })
             : branch.buildPayload({
                 message: body.message,
@@ -999,6 +1010,7 @@ export async function handleUnifiedChatPost(req: NextRequest) {
                 userTimezone: body.userTimezone,
                 userMetadata,
                 workspaceContext,
+                vfs,
               }),
         activeOtelRoot.context
       )

apps/sim/lib/copilot/chat/workspace-context.test.ts

@@ -116,3 +116,157 @@ describe('buildWorkspaceMd - connected integrations / credentials', () => {
     expect(md).toContain('## Connected Integrations\n(none)')
   })
 })
+
+describe('buildWorkspaceMd - determinism (prompt-cache stability)', () => {
+  it('is byte-identical regardless of input row order', () => {
+    const a = buildWorkspaceMd(
+      baseData({
+        members: [
+          { name: 'Bob', email: 'bob@x.com', permissionType: 'admin' },
+          { name: 'Amy', email: 'amy@x.com', permissionType: 'write' },
+        ],
+        workflows: [
+          { id: 'wf-2', name: 'Zeta', isDeployed: false, folderPath: null },
+          { id: 'wf-1', name: 'Alpha', isDeployed: true, folderPath: null },
+        ],
+        tables: [
+          { id: 't-2', name: 'Orders', description: null, rowCount: 5 },
+          { id: 't-1', name: 'Customers', description: null, rowCount: 9 },
+        ],
+        knowledgeBases: [
+          { id: 'kb-2', name: 'Docs', connectorTypes: ['notion', 'github'] },
+          { id: 'kb-1', name: 'Articles', connectorTypes: ['github', 'notion'] },
+        ],
+        oauthIntegrations: [
+          { id: 'c-2', providerId: 'slack', displayName: null, role: null },
+          { id: 'c-1', providerId: 'github', displayName: null, role: null },
+        ],
+        envVariables: ['ZED', 'API_KEY'],
+        customTools: [
+          { id: 'ct-2', name: 'Beta Tool' },
+          { id: 'ct-1', name: 'Alpha Tool' },
+        ],
+        mcpServers: [
+          { id: 'mcp-2', name: 'Zulu', url: null, enabled: false },
+          { id: 'mcp-1', name: 'Mike', url: 'https://x', enabled: true },
+        ],
+        skills: [
+          { id: 'sk-2', name: 'Writer', description: 'writes' },
+          { id: 'sk-1', name: 'Editor', description: 'edits' },
+        ],
+        jobs: [
+          {
+            id: 'j-2',
+            title: 'Nightly',
+            prompt: 'run nightly',
+            cronExpression: '0 0 * * *',
+            status: 'active',
+            lifecycle: 'persistent',
+            sourceTaskName: null,
+          },
+          {
+            id: 'j-1',
+            title: 'Hourly',
+            prompt: 'run hourly',
+            cronExpression: '0 * * * *',
+            status: 'active',
+            lifecycle: 'persistent',
+            sourceTaskName: null,
+          },
+        ],
+      })
+    )
+    const b = buildWorkspaceMd(
+      baseData({
+        members: [
+          { name: 'Amy', email: 'amy@x.com', permissionType: 'write' },
+          { name: 'Bob', email: 'bob@x.com', permissionType: 'admin' },
+        ],
+        workflows: [
+          { id: 'wf-1', name: 'Alpha', isDeployed: true, folderPath: null },
+          { id: 'wf-2', name: 'Zeta', isDeployed: false, folderPath: null },
+        ],
+        tables: [
+          { id: 't-1', name: 'Customers', description: null, rowCount: 9 },
+          { id: 't-2', name: 'Orders', description: null, rowCount: 5 },
+        ],
+        knowledgeBases: [
+          { id: 'kb-1', name: 'Articles', connectorTypes: ['notion', 'github'] },
+          { id: 'kb-2', name: 'Docs', connectorTypes: ['github', 'notion'] },
+        ],
+        oauthIntegrations: [
+          { id: 'c-1', providerId: 'github', displayName: null, role: null },
+          { id: 'c-2', providerId: 'slack', displayName: null, role: null },
+        ],
+        envVariables: ['API_KEY', 'ZED'],
+        customTools: [
+          { id: 'ct-1', name: 'Alpha Tool' },
+          { id: 'ct-2', name: 'Beta Tool' },
+        ],
+        mcpServers: [
+          { id: 'mcp-1', name: 'Mike', url: 'https://x', enabled: true },
+          { id: 'mcp-2', name: 'Zulu', url: null, enabled: false },
+        ],
+        skills: [
+          { id: 'sk-1', name: 'Editor', description: 'edits' },
+          { id: 'sk-2', name: 'Writer', description: 'writes' },
+        ],
+        jobs: [
+          {
+            id: 'j-1',
+            title: 'Hourly',
+            prompt: 'run hourly',
+            cronExpression: '0 * * * *',
+            status: 'active',
+            lifecycle: 'persistent',
+            sourceTaskName: null,
+          },
+          {
+            id: 'j-2',
+            title: 'Nightly',
+            prompt: 'run nightly',
+            cronExpression: '0 0 * * *',
+            status: 'active',
+            lifecycle: 'persistent',
+            sourceTaskName: null,
+          },
+        ],
+      })
+    )
+    expect(a).toBe(b)
+  })
+
+  it('ignores volatile workflow run timestamps', () => {
+    const withRun = buildWorkspaceMd(
+      baseData({
+        workflows: [
+          {
+            id: 'wf-1',
+            name: 'Alpha',
+            isDeployed: false,
+            folderPath: null,
+            lastRunAt: new Date('2026-06-18T12:00:00Z'),
+          },
+        ],
+      })
+    )
+    const withoutRun = buildWorkspaceMd(
+      baseData({
+        workflows: [{ id: 'wf-1', name: 'Alpha', isDeployed: false, folderPath: null }],
+      })
+    )
+    expect(withRun).toBe(withoutRun)
+    expect(withRun).not.toContain('last run')
+  })
+
+  it('ignores volatile table row counts', () => {
+    const a = buildWorkspaceMd(
+      baseData({ tables: [{ id: 't-1', name: 'Customers', description: null, rowCount: 1 }] })
+    )
+    const b = buildWorkspaceMd(
+      baseData({ tables: [{ id: 't-1', name: 'Customers', description: null, rowCount: 9999 }] })
+    )
+    expect(a).toBe(b)
+    expect(a).not.toContain('rows')
+  })
+})