simstudioai · j15z · Aug 12, 2026 · Aug 12, 2026 · Aug 12, 2026 · Aug 12, 2026
diff --git a/apps/sim/lib/copilot/tools/handlers/vfs.test.ts b/apps/sim/lib/copilot/tools/handlers/vfs.test.ts
@@ -313,6 +313,50 @@ describe('vfs handlers oversize policy', () => {
     expect(vfs.read).not.toHaveBeenCalled()
   })
 
+  it('surfaces dynamic file read errors as failed tool calls', async () => {
+    const vfs = makeVfs()
+    const error = 'Document compiler not configured (MOTHERSHIP_E2B_DOC_TEMPLATE_ID is unset)'
+    vfs.readFileContent.mockResolvedValue({
+      content: JSON.stringify({ ok: false, error }),
+      totalLines: 1,
+      error,
+    })
+    getOrMaterializeVFS.mockResolvedValue(vfs)
+
+    const result = await executeVfsRead({ path: 'files/reports/brief.pdf/render' }, GREP_CTX)
+
+    expect(result).toEqual({ success: false, error })
+  })
+
+  it('does not expose dynamic file read errors when provenance cannot be verified', async () => {
+    const vfs = makeVfs()
+    const error = 'Document compiler not configured (MOTHERSHIP_E2B_DOC_TEMPLATE_ID is unset)'
+    vfs.readFileContentWithProvenance.mockResolvedValue({
+      value: {
+        content: JSON.stringify({ ok: false, error }),
+        totalLines: 1,
+        error,
+      },
+      file: { fileId: 'file-1', key: 'workspace/key-1', context: 'workspace' },
+    })
+    getOrMaterializeVFS.mockResolvedValue(vfs)
+    importWorkspaceFileSecretProvenanceForModelView.mockResolvedValueOnce(false)
+
+    const result = await executeVfsRead({ path: 'files/reports/brief.pdf/render' }, GREP_CTX)
+
+    expect(result).toEqual({
+      success: false,
+      error:
+        'This file result cannot be shared safely because its secret provenance is unavailable.',
+    })
+    expect(importWorkspaceFileSecretProvenanceForModelView).toHaveBeenCalledWith(
+      expect.objectContaining({
+        identity: { fileId: 'file-1', key: 'workspace/key-1', context: 'workspace' },
+        view: 'derived',
+      })
+    )
+  })
+
   it('marks a windowed read as a derived provenance view', async () => {
     const vfs = makeVfs()
     vfs.readFileContentWithProvenance.mockResolvedValue({

diff --git a/apps/sim/lib/copilot/tools/handlers/vfs.ts b/apps/sim/lib/copilot/tools/handlers/vfs.ts
@@ -442,6 +442,9 @@ export async function executeVfsRead(
             'This file result cannot be shared safely because its secret provenance is unavailable.',
         }
       }
+      if (fileContent.error !== undefined) {
+        return { success: false, error: fileContent.error }
+      }
       logger.debug('vfs_read resolved workspace file', {
         path,
         totalLines: fileContent.totalLines,

diff --git a/apps/sim/lib/copilot/vfs/file-reader.ts b/apps/sim/lib/copilot/vfs/file-reader.ts
@@ -447,6 +447,8 @@ export interface FileReadResult {
   totalLines: number
   /** Set when `content` stands in for the file rather than being it — see `readPlaceholder`. */
   placeholder?: PlaceholderKind
+  /** Set when a dynamic read resolved the file but failed to produce its requested view. */
+  error?: string
   attachment?: {
     type: string
     name?: string

diff --git a/apps/sim/lib/copilot/vfs/workspace-vfs.test.ts b/apps/sim/lib/copilot/vfs/workspace-vfs.test.ts
@@ -0,0 +1,132 @@
+/**
+ * @vitest-environment node
+ */
+
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+
+const { renderDocToGrid } = vi.hoisted(() => ({
+  renderDocToGrid: vi.fn(),
+}))
+
+const { findWorkspaceFileRecord, listAllWorkspaceFilesExecute, readWorkspaceFileContentExecute } =
+  vi.hoisted(() => ({
+    findWorkspaceFileRecord: vi.fn(),
+    listAllWorkspaceFilesExecute: vi.fn(),
+    readWorkspaceFileContentExecute: vi.fn(),
+  }))
+
+vi.mock('@/lib/copilot/tools/server/files/doc-render', () => ({
+  // `odt` exposes the defensive missing-task branch independently from the extension guard.
+  isRenderableDocExt: (ext: string) => ['docx', 'odt', 'pdf', 'pptx'].includes(ext.toLowerCase()),
+  renderDocToGrid,
+}))
+
+vi.mock('@/lib/uploads/contexts/workspace/workspace-file-manager', () => ({
+  findWorkspaceFileRecord,
+}))
+
+vi.mock('@/lib/workspace-files/application/list-workspace-files', () => ({
+  listAllWorkspaceFiles: { execute: listAllWorkspaceFilesExecute },
+}))
+
+vi.mock('@/lib/workspace-files/application/read-workspace-file-content', () => ({
+  readWorkspaceFileContent: { execute: readWorkspaceFileContentExecute },
+}))
+
+import { WorkspaceVFS } from '@/lib/copilot/vfs/workspace-vfs'
+
+const MAX_DOC_READ_INPUT_BYTES = 50 * 1024 * 1024
+const MAX_DOCUMENT_PREVIEW_CODE_BYTES = 1024 * 1024
+
+function arrangeRenderRead({
+  name = 'brief.pdf',
+  size = 8,
+  content = Buffer.from('%PDF-1.7'),
+}: {
+  name?: string
+  size?: number
+  content?: Buffer | { length: number }
+} = {}) {
+  const record = {
+    id: 'file-1',
+    workspaceId: 'ws-1',
+    name,
+    key: name,
+    path: `/api/files/serve/${name}`,
+    size,
+    type: 'application/octet-stream',
+    uploadedBy: 'user-1',
+    deletedAt: null,
+    uploadedAt: new Date('2026-01-01T00:00:00.000Z'),
+    updatedAt: new Date('2026-01-01T00:00:00.000Z'),
+    storageContext: 'mothership' as const,
+  }
+  listAllWorkspaceFilesExecute.mockResolvedValue({ files: [record] })
+  findWorkspaceFileRecord.mockReturnValue(record)
+  readWorkspaceFileContentExecute.mockResolvedValue({ content })
+
+  const vfs = new WorkspaceVFS({ kind: 'session', userId: 'user-1', sessionId: 'session-1' })
+  Object.assign(vfs, { _workspaceId: 'ws-1' })
+  return vfs
+}
+
+describe('WorkspaceVFS dynamic render reads', () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+  })
+
+  it('marks render exceptions as file read errors', async () => {
+    const vfs = arrangeRenderRead()
+    renderDocToGrid.mockRejectedValue(
+      new Error('Document compiler not configured (MOTHERSHIP_E2B_DOC_TEMPLATE_ID is unset)')
+    )
+
+    const result = await vfs.readFileContent('files/brief.pdf/render')
+
+    expect(result).toEqual({
+      content:
+        '{"ok":false,"error":"Document compiler not configured (MOTHERSHIP_E2B_DOC_TEMPLATE_ID is unset)"}',
+      totalLines: 1,
+      error: 'Document compiler not configured (MOTHERSHIP_E2B_DOC_TEMPLATE_ID is unset)',
+    })
+  })
+
+  it.each([
+    {
+      label: 'unsupported extensions',
+      name: 'brief.txt',
+      error: 'Render supports .pptx, .docx, and .pdf only',
+    },
+    {
+      label: 'oversized file metadata',
+      size: MAX_DOC_READ_INPUT_BYTES + 1,
+      error: 'File is too large to render',
+    },
+    {
+      label: 'oversized fetched buffers',
+      content: { length: MAX_DOC_READ_INPUT_BYTES + 1 },
+      error: 'File is too large to render',
+    },
+    {
+      label: 'oversized source',
+      content: Buffer.alloc(MAX_DOCUMENT_PREVIEW_CODE_BYTES + 1, 'a'),
+      error: 'File source exceeds maximum size',
+    },
+    {
+      label: 'missing render tasks',
+      name: 'brief.odt',
+      content: Buffer.from('document source'),
+      error: 'Cannot render this file',
+    },
+  ])('marks $label as file read errors', async ({ name, size, content, error }) => {
+    const vfs = arrangeRenderRead({ name, size, content })
+
+    const result = await vfs.readFileContent(`files/${name ?? 'brief.pdf'}/render`)
+
+    expect(result).toEqual({
+      content: JSON.stringify({ ok: false, error }),
+      totalLines: 1,
+      error,
+    })
+  })
+})
diff --git a/apps/sim/lib/copilot/vfs/workspace-vfs.ts b/apps/sim/lib/copilot/vfs/workspace-vfs.ts
@@ -184,6 +184,14 @@ function bindWorkspaceFileResult<T>(
   }
 }
 
+function renderErrorResult(error: string): FileReadResult {
+  return {
+    content: JSON.stringify({ ok: false, error }),
+    totalLines: 1,
+    error,
+  }
+}
+
 function recordContributingFile(
   files: Map<string, WorkspaceFileSecretProvenanceIdentity>,
   identity: WorkspaceFileSecretProvenanceIdentity
@@ -1103,10 +1111,7 @@ export class WorkspaceVFS {
     contributingFiles: Map<string, WorkspaceFileSecretProvenanceIdentity>
   ): Promise<FileReadResult> {
     if (typeof record.size === 'number' && record.size > MAX_DOC_READ_INPUT_BYTES) {
-      return {
-        content: JSON.stringify({ ok: false, error: 'File is too large to render' }),
-        totalLines: 1,
-      }
+      return renderErrorResult('File is too large to render')
     }
     const { content: buffer } = await readWorkspaceFileContent.execute({
       principal: this.requireFilePrincipal(),
@@ -1117,10 +1122,7 @@ export class WorkspaceVFS {
       },
     })
     if (buffer.length > MAX_DOC_READ_INPUT_BYTES) {
-      return {
-        content: JSON.stringify({ ok: false, error: 'File is too large to render' }),
-        totalLines: 1,
-      }
+      return renderErrorResult('File is too large to render')
     }
     // Already-binary uploads render directly; source files are compiled first
     // (E2B regime -> doc sandbox: Node pptx/docx, Python pdf; otherwise
@@ -1131,10 +1133,7 @@ export class WorkspaceVFS {
     } else {
       const code = buffer.toString('utf-8')
       if (Buffer.byteLength(code, 'utf-8') > MAX_DOCUMENT_PREVIEW_CODE_BYTES) {
-        return {
-          content: JSON.stringify({ ok: false, error: 'File source exceeds maximum size' }),
-          totalLines: 1,
-        }
+        return renderErrorResult('File source exceeds maximum size')
       }
       if (isDocSandboxEnabled && (await getE2BDocFormat(record.name))) {
         bin = (
@@ -1148,10 +1147,7 @@ export class WorkspaceVFS {
       } else {
         const taskId = BINARY_DOC_TASKS[ext]
         if (!taskId) {
-          return {
-            content: JSON.stringify({ ok: false, error: 'Cannot render this file' }),
-            totalLines: 1,
-          }
+          return renderErrorResult('Cannot render this file')
         }
         bin = await runSandboxTask(
           taskId,
@@ -1337,13 +1333,10 @@ export class WorkspaceVFS {
         if (!record) return null
         const ext = record.name.split('.').pop()?.toLowerCase() ?? ''
         if (!isRenderableDocExt(ext)) {
-          return bindWorkspaceFileResult(record, {
-            content: JSON.stringify({
-              ok: false,
-              error: 'Render supports .pptx, .docx, and .pdf only',
-            }),
-            totalLines: 1,
-          })
+          return bindWorkspaceFileResult(
+            record,
+            renderErrorResult('Render supports .pptx, .docx, and .pdf only')
+          )
         }
         const renderName = record.name
         const rendered = await this.renderDocRecordResult(
@@ -1355,19 +1348,17 @@ export class WorkspaceVFS {
         )
         return bindWorkspaceFileResult(record, rendered, 'derived', [...contributingFiles.values()])
       } catch (err) {
+        const error = toError(err).message
         logger.warn('Render read failed via VFS', {
           workspaceId: this._workspaceId,
           path,
           fileId: record?.id,
-          error: toError(err).message,
+          error,
         })
         // Return an explicit error (not null) once the file resolved — a null read
         // looks like a missing path and sends the agent hunting for the "correct"
         // render path instead of surfacing the real compile/render failure.
-        const errorResult = {
-          content: JSON.stringify({ ok: false, error: toError(err).message }),
-          totalLines: 1,
-        }
+        const errorResult = renderErrorResult(error)
         return record ? bindWorkspaceFileResult(record, errorResult) : { value: errorResult }
       }
     }