diff --git a/apps/sim/app/api/folders/route.test.ts b/apps/sim/app/api/folders/route.test.ts
index a72c0a7bbf8..baafe6fd2ad 100644
--- a/apps/sim/app/api/folders/route.test.ts
+++ b/apps/sim/app/api/folders/route.test.ts
@@ -9,6 +9,7 @@ import {
   createMockRequest,
   permissionsMock,
   permissionsMockFns,
+  workflowAuthzMockFns,
 } from '@sim/testing'
 import { drizzleOrmMock } from '@sim/testing/mocks'
 import { beforeEach, describe, expect, it, vi } from 'vitest'
@@ -390,6 +391,26 @@ describe('Folders API Route', () => {
       })
     })
 
+    it('should reject creating a subfolder inside a locked parent folder', async () => {
+      mockAuthenticatedUser()
+
+      const { FolderLockedError } = await import('@sim/workflow-authz')
+      workflowAuthzMockFns.mockAssertFolderMutable.mockRejectedValueOnce(
+        new FolderLockedError('Folder is locked')
+      )
+
+      const req = createMockRequest('POST', {
+        name: 'Subfolder',
+        workspaceId: 'workspace-123',
+        parentId: 'locked-folder',
+      })
+
+      const response = await POST(req)
+
+      expect(response.status).toBe(423)
+      expect(mockTransaction).not.toHaveBeenCalled()
+    })
+
     it('should reject a parentId that does not resolve to a folder in the workspace', async () => {
       mockAuthenticatedUser()
 
diff --git a/apps/sim/app/api/folders/route.ts b/apps/sim/app/api/folders/route.ts
index 404ebe0873c..f359e376542 100644
--- a/apps/sim/app/api/folders/route.ts
+++ b/apps/sim/app/api/folders/route.ts
@@ -1,6 +1,7 @@
 import { db } from '@sim/db'
 import { workflowFolder } from '@sim/db/schema'
 import { createLogger } from '@sim/logger'
+import { assertFolderMutable, FolderLockedError } from '@sim/workflow-authz'
 import { and, asc, eq, isNotNull, isNull } from 'drizzle-orm'
 import { type NextRequest, NextResponse } from 'next/server'
 import { createFolderContract, listFoldersContract } from '@/lib/api/contracts'
@@ -93,6 +94,8 @@ export const POST = withRouteHandler(async (request: NextRequest) => {
       )
     }
 
+    await assertFolderMutable(parentId ?? null)
+
     const result = await performCreateFolder({
       id: clientId,
       userId: session.user.id,
@@ -123,6 +126,9 @@ export const POST = withRouteHandler(async (request: NextRequest) => {
 
     return NextResponse.json({ folder: newFolder })
   } catch (error) {
+    if (error instanceof FolderLockedError) {
+      return NextResponse.json({ error: error.message }, { status: error.status })
+    }
     logger.error('Error creating folder:', { error })
     return NextResponse.json({ error: 'Internal server error' }, { status: 500 })
   }
diff --git a/apps/sim/app/api/workflows/route.test.ts b/apps/sim/app/api/workflows/route.test.ts
index 30e75ad2ed7..2bfddb39343 100644
--- a/apps/sim/app/api/workflows/route.test.ts
+++ b/apps/sim/app/api/workflows/route.test.ts
@@ -7,6 +7,7 @@ import {
   hybridAuthMockFns,
   permissionsMock,
   permissionsMockFns,
+  workflowAuthzMockFns,
   workflowsApiUtilsMock,
   workflowsPersistenceUtilsMock,
   workflowsPersistenceUtilsMockFns,
@@ -80,11 +81,30 @@ describe('Workflows API Route - POST ordering', () => {
       userEmail: 'test@example.com',
     })
     mockGetUserEntityPermissions.mockResolvedValue('write')
+    workflowAuthzMockFns.mockAssertFolderMutable.mockResolvedValue(undefined)
     workflowsPersistenceUtilsMockFns.mockSaveWorkflowToNormalizedTables.mockResolvedValue({
       success: true,
     })
   })
 
+  it('rejects creating a workflow inside a locked folder', async () => {
+    const { FolderLockedError } = await import('@sim/workflow-authz')
+    workflowAuthzMockFns.mockAssertFolderMutable.mockRejectedValueOnce(
+      new FolderLockedError('Folder is locked')
+    )
+
+    const req = createMockRequest('POST', {
+      name: 'New Workflow',
+      description: 'desc',
+      workspaceId: 'workspace-123',
+      folderId: 'locked-folder',
+    })
+
+    const response = await POST(req)
+    expect(response.status).toBe(423)
+    expect(mockDbInsert).not.toHaveBeenCalled()
+  })
+
   it('uses top insertion against mixed siblings (folders + workflows)', async () => {
     const minResultsQueue: Array<Array<{ minOrder: number }>> = [
       [],
diff --git a/apps/sim/app/api/workflows/route.ts b/apps/sim/app/api/workflows/route.ts
index 92a17985965..224cb68417d 100644
--- a/apps/sim/app/api/workflows/route.ts
+++ b/apps/sim/app/api/workflows/route.ts
@@ -1,4 +1,5 @@
 import { createLogger } from '@sim/logger'
+import { assertFolderMutable, FolderLockedError } from '@sim/workflow-authz'
 import { type NextRequest, NextResponse } from 'next/server'
 import { createWorkflowContract, workflowListQuerySchema } from '@/lib/api/contracts/workflows'
 import { parseRequest } from '@/lib/api/server'
@@ -116,6 +117,8 @@ export const POST = withRouteHandler(async (req: NextRequest) => {
       )
     }
 
+    await assertFolderMutable(folderId ?? null)
+
     const result = await performCreateWorkflow({
       id: clientId,
       name: requestedName,
@@ -180,6 +183,9 @@ export const POST = withRouteHandler(async (req: NextRequest) => {
       subBlockValues: createdWorkflow.subBlockValues,
     })
   } catch (error) {
+    if (error instanceof FolderLockedError) {
+      return NextResponse.json({ error: error.message }, { status: error.status })
+    }
     logger.error(`[${requestId}] Error creating workflow`, error)
     return NextResponse.json({ error: 'Failed to create workflow' }, { status: 500 })
   }
diff --git a/apps/sim/lib/copilot/tools/handlers/workflow/mutations.test.ts b/apps/sim/lib/copilot/tools/handlers/workflow/mutations.test.ts
index 582c42c6a6b..037894bf30c 100644
--- a/apps/sim/lib/copilot/tools/handlers/workflow/mutations.test.ts
+++ b/apps/sim/lib/copilot/tools/handlers/workflow/mutations.test.ts
@@ -1,7 +1,7 @@
 /**
  * @vitest-environment node
  */
-import { createEnvMock } from '@sim/testing'
+import { createEnvMock, workflowAuthzMockFns } from '@sim/testing'
 import { beforeEach, describe, expect, it, vi } from 'vitest'
 
 const {
@@ -88,7 +88,16 @@ vi.mock('../access', () => ({
   getDefaultWorkspaceId: vi.fn(),
 }))
 
-import { executeRunFromBlock, executeSetGlobalWorkflowVariables } from './mutations'
+import { performUpdateWorkflow } from '@/lib/workflows/orchestration'
+import { verifyFolderWorkspace } from '@/lib/workflows/utils'
+import {
+  executeMoveWorkflow,
+  executeRunFromBlock,
+  executeSetGlobalWorkflowVariables,
+} from './mutations'
+
+const performUpdateWorkflowMock = vi.mocked(performUpdateWorkflow)
+const verifyFolderWorkspaceMock = vi.mocked(verifyFolderWorkspace)
 
 describe('executeSetGlobalWorkflowVariables', () => {
   beforeEach(() => {
@@ -134,6 +143,56 @@ describe('executeSetGlobalWorkflowVariables', () => {
   })
 })
 
+describe('lock enforcement', () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+    global.fetch = vi.fn().mockResolvedValue(new Response(null, { status: 200 })) as typeof fetch
+    workflowAuthzMockFns.mockAssertWorkflowMutable.mockResolvedValue(undefined)
+    workflowAuthzMockFns.mockAssertFolderMutable.mockResolvedValue(undefined)
+  })
+
+  it('does not persist variable changes when the workflow is locked', async () => {
+    ensureWorkflowAccessMock.mockResolvedValue({
+      workflow: { id: 'workflow-1', variables: {} },
+    })
+    workflowAuthzMockFns.mockAssertWorkflowMutable.mockRejectedValueOnce(
+      new Error('Workflow is locked')
+    )
+
+    const result = await executeSetGlobalWorkflowVariables(
+      {
+        workflowId: 'workflow-1',
+        operations: [{ operation: 'add', name: 'threshold', type: 'number', value: '5' }],
+      },
+      { userId: 'user-1' } as any
+    )
+
+    expect(result.success).toBe(false)
+    expect(result.error).toBe('Workflow is locked')
+    expect(setWorkflowVariablesMock).not.toHaveBeenCalled()
+  })
+
+  it('does not move a workflow into a locked target folder', async () => {
+    ensureWorkflowAccessMock.mockResolvedValue({
+      workspaceId: 'workspace-1',
+      workflow: { id: 'workflow-1', name: 'WF', folderId: null },
+    })
+    verifyFolderWorkspaceMock.mockResolvedValue(true)
+    workflowAuthzMockFns.mockAssertFolderMutable.mockRejectedValueOnce(
+      new Error('Folder is locked')
+    )
+
+    const result = await executeMoveWorkflow(
+      { workflowIds: ['workflow-1'], folderId: 'locked-folder' },
+      { userId: 'user-1' } as any
+    )
+
+    expect(result.success).toBe(false)
+    expect(result.error).toBe('Folder is locked')
+    expect(performUpdateWorkflowMock).not.toHaveBeenCalled()
+  })
+})
+
 describe('executeRunFromBlock', () => {
   beforeEach(() => {
     vi.clearAllMocks()
diff --git a/apps/sim/lib/copilot/tools/handlers/workflow/mutations.ts b/apps/sim/lib/copilot/tools/handlers/workflow/mutations.ts
index 115f8ff3590..7ae8c2e6a4d 100644
--- a/apps/sim/lib/copilot/tools/handlers/workflow/mutations.ts
+++ b/apps/sim/lib/copilot/tools/handlers/workflow/mutations.ts
@@ -3,6 +3,7 @@ import { db, workflow as workflowTable } from '@sim/db'
 import { createLogger } from '@sim/logger'
 import { toError } from '@sim/utils/errors'
 import { generateId } from '@sim/utils/id'
+import { assertFolderMutable, assertWorkflowMutable } from '@sim/workflow-authz'
 import { mergeSubblockStateWithValues } from '@sim/workflow-persistence/subblocks'
 import { eq } from 'drizzle-orm'
 import { performCreateWorkspaceApiKey } from '@/lib/api-key/orchestration'
@@ -353,6 +354,7 @@ export async function executeCreateWorkflow(
     const folderId = params?.folderId || null
 
     await ensureWorkspaceAccess(workspaceId, context.userId, 'write')
+    await assertFolderMutable(folderId)
     assertWorkflowMutationNotAborted(context)
 
     const result = await performCreateWorkflow({
@@ -422,6 +424,7 @@ export async function executeCreateFolder(
     const parentId = params?.parentId || null
 
     await ensureWorkspaceAccess(workspaceId, context.userId, 'write')
+    await assertFolderMutable(parentId)
     assertWorkflowMutationNotAborted(context)
 
     const result = await performCreateFolder({
@@ -512,6 +515,7 @@ export async function executeSetGlobalWorkflowVariables(
       context.userId,
       'write'
     )
+    await assertWorkflowMutable(workflowId)
 
     interface WorkflowVariable {
       id: string
@@ -633,9 +637,9 @@ export async function executeRenameWorkflow(
       return { success: false, error: 'Workflow name must be 200 characters or less' }
     }
 
-    await ensureWorkflowAccess(workflowId, context.userId, 'write')
-    assertWorkflowMutationNotAborted(context)
     const current = await ensureWorkflowAccess(workflowId, context.userId, 'write')
+    await assertWorkflowMutable(workflowId)
+    assertWorkflowMutationNotAborted(context)
     if (!current.workspaceId) {
       return { success: false, error: 'Workflow workspace is required' }
     }
@@ -671,6 +675,8 @@ export async function executeMoveWorkflow(
     const moved: string[] = []
     const failed: string[] = []
 
+    await assertFolderMutable(folderId)
+
     for (const workflowId of workflowIds) {
       try {
         const { workspaceId, workflow } = await ensureWorkflowAccess(
@@ -688,6 +694,7 @@ export async function executeMoveWorkflow(
             continue
           }
         }
+        await assertWorkflowMutable(workflowId)
         assertWorkflowMutationNotAborted(context)
         const result = await performUpdateWorkflow({
           workflowId,
@@ -735,6 +742,8 @@ export async function executeMoveFolder(
       return { success: false, error: 'Parent folder not found' }
     }
 
+    await assertFolderMutable(folderId)
+    await assertFolderMutable(parentId)
     assertWorkflowMutationNotAborted(context)
     const result = await performUpdateFolder({
       folderId,
@@ -941,6 +950,7 @@ async function executeUpdateWorkflow(
     if (!current.workspaceId) {
       return { success: false, error: 'Workflow workspace is required' }
     }
+    await assertWorkflowMutable(workflowId)
     assertWorkflowMutationNotAborted(context)
     const result = await performUpdateWorkflow({
       workflowId,
@@ -984,6 +994,7 @@ export async function executeSetBlockEnabled(
       context.userId,
       'write'
     )
+    await assertWorkflowMutable(workflowId)
     assertWorkflowMutationNotAborted(context)
 
     const normalized = await loadWorkflowFromNormalizedTables(workflowId)
@@ -1114,6 +1125,7 @@ export async function executeDeleteWorkflow(
           context.userId,
           'write'
         )
+        await assertWorkflowMutable(workflowId)
         assertWorkflowMutationNotAborted(context)
 
         const result = await performDeleteWorkflow({ workflowId, userId: context.userId })
@@ -1162,16 +1174,22 @@ export async function executeDeleteFolder(
 
       assertWorkflowMutationNotAborted(context)
 
-      const result = await performDeleteFolder({
-        folderId,
-        workspaceId,
-        userId: context.userId,
-        folderName: folder.folderName,
-      })
+      try {
+        await assertFolderMutable(folderId)
 
-      if (result.success) {
-        deleted.push(folderId)
-      } else {
+        const result = await performDeleteFolder({
+          folderId,
+          workspaceId,
+          userId: context.userId,
+          folderName: folder.folderName,
+        })
+
+        if (result.success) {
+          deleted.push(folderId)
+        } else {
+          failed.push(folderId)
+        }
+      } catch {
         failed.push(folderId)
       }
     }
@@ -1206,6 +1224,7 @@ async function executeRenameFolder(
       return { success: false, error: 'Folder not found' }
     }
 
+    await assertFolderMutable(folderId)
     assertWorkflowMutationNotAborted(context)
     const result = await performUpdateFolder({
       folderId,
diff --git a/apps/sim/lib/copilot/tools/server/workflow/edit-workflow/index.ts b/apps/sim/lib/copilot/tools/server/workflow/edit-workflow/index.ts
index 44bb0ee4a8c..96a4fa98353 100644
--- a/apps/sim/lib/copilot/tools/server/workflow/edit-workflow/index.ts
+++ b/apps/sim/lib/copilot/tools/server/workflow/edit-workflow/index.ts
@@ -2,7 +2,7 @@ import { db } from '@sim/db'
 import { workflow as workflowTable } from '@sim/db/schema'
 import { createLogger } from '@sim/logger'
 import { toError } from '@sim/utils/errors'
-import { authorizeWorkflowByWorkspacePermission } from '@sim/workflow-authz'
+import { assertWorkflowMutable, authorizeWorkflowByWorkspacePermission } from '@sim/workflow-authz'
 import { eq } from 'drizzle-orm'
 import { EditWorkflow } from '@/lib/copilot/generated/tool-catalog-v1'
 import {
@@ -106,6 +106,8 @@ export const editWorkflowServerTool: BaseServerTool<EditWorkflowParams, unknown>
       throw new Error(authorization.message || 'Unauthorized workflow access')
     }
 
+    await assertWorkflowMutable(workflowId)
+
     const workspaceId = authorization.workflow?.workspaceId ?? undefined
     const workflowName = authorization.workflow?.name ?? undefined