feat: add modular artifact format validation

example.env

@@ -867,6 +867,11 @@ XAGENT_EXTERNAL_SKILLS_LIBRARY_DIRS=""
 # Supports raw bytes or human-readable values like 100M, 1G, 512K.
 XAGENT_MAX_UPLOAD_SIZE="100M"
 
+# Format-readability validation for generated artifacts. Unsupported formats,
+# absent optional parsers and exhausted budgets are reported as unchecked.
+XAGENT_ARTIFACT_VALIDATION_MAX_BYTES=33554432
+XAGENT_ARTIFACT_VALIDATION_TIMEOUT_SECONDS=8
+
 # Durable file storage for user-visible uploads and registered workspace outputs.
 # Defaults to file://$XAGENT_STORAGE_ROOT/files for local development.
 # For S3-compatible storage, use a URI with bucket and optional prefix.

frontend/src/components/file/artifact-validation.test.tsx

@@ -0,0 +1,85 @@
+/// <reference types="@testing-library/jest-dom/vitest" />
+import React from 'react'
+import { act, cleanup, fireEvent, render, screen, waitFor } from '@testing-library/react'
+import { afterEach, describe, expect, it, vi } from 'vitest'
+import { ArtifactValidation } from './artifact-validation'
+import { FileAccessProvider, defaultFileAccessPolicy, createPublicFileAccessPolicy } from '@/contexts/file-access-context'
+import { I18nProvider } from '@/contexts/i18n-context'
+import { InlineFilePreview } from './inline-file-preview'
+
+const reportHeaders = { 'content-type': 'application/vnd.xagent.validation+json' }
+const report = (status: string, message = '') => new Response(JSON.stringify({ status, sha256: '0'.repeat(64), checks: [{ status, message }] }), { headers: reportHeaders })
+const wrap = (children: React.ReactNode, request = vi.fn(), extra = {}) => <I18nProvider>
+  <FileAccessProvider policy={{ ...defaultFileAccessPolicy, request, ...extra }}>{children}</FileAccessProvider>
+</I18nProvider>
+
+afterEach(() => { cleanup(); vi.unstubAllGlobals() })
+
+describe('ArtifactValidation', () => {
+  it.each(['valid', 'invalid', 'unchecked'] as const)('shows %s without hiding repair/download access', async status => {
+    const request = vi.fn().mockResolvedValue(report(status, status === 'invalid' ? 'Corrupt package' : ''))
+    const { container } = render(wrap(<ArtifactValidation fileId="one"><a href="/download">artifact</a></ArtifactValidation>, request))
+    expect(container.querySelector('[data-artifact-validation="checking"]')).toBeTruthy()
+    await waitFor(() => expect(container.querySelector(`[data-artifact-validation="${status}"]`)).toBeTruthy())
+    expect(screen.getByRole('link', { name: 'artifact' })).toHaveAttribute('href', '/download')
+    expect(request).toHaveBeenCalledWith('/api/files/preview/one?validation_only=true', expect.objectContaining({ cache: 'no-store', signal: expect.any(AbortSignal) }))
+  })
+
+  it('rechecks the same file id after repair without reusing a cached pass', async () => {
+    const request = vi.fn().mockResolvedValueOnce(report('valid')).mockResolvedValueOnce(report('invalid', 'broken'))
+    const { container } = render(wrap(<ArtifactValidation fileId="one">file</ArtifactValidation>, request))
+    await screen.findByText('Format readable · content not verified')
+    fireEvent.click(screen.getByRole('button', { name: 'Recheck' }))
+    expect(container.querySelector('[data-artifact-validation="checking"]')).toBeTruthy()
+    await screen.findByText('File validation failed · repair required')
+    expect(request).toHaveBeenCalledTimes(2)
+  })
+
+  it.each([
+    new Response('', { status: 403 }), report('made-up'), new Response('not json'),
+    new Response('{"status":"valid"}', { headers: reportHeaders }),
+    new Response('{"status":"valid","checks":[{"status":"valid"}]}', { headers: reportHeaders }),
+    new Response(JSON.stringify({ status: 'valid', sha256: '0'.repeat(64), checks: [{ status: 'unchecked' }] }), { headers: reportHeaders }),
+    new Response(JSON.stringify({ status: 'valid', sha256: '0'.repeat(64), checks: [{ status: 'valid' }] }), { headers: { 'content-type': 'application/json' } }),
+  ])('does not treat a failed/malformed request as a pass', async response => {
+    render(wrap(<ArtifactValidation fileId="one">file</ArtifactValidation>, vi.fn().mockResolvedValue(response)))
+    await screen.findByText('File not checked')
+  })
+
+  it('ignores an old response after the file changes', async () => {
+    let finish!: (response: Response) => void
+    const request = vi.fn().mockImplementationOnce(() => new Promise(resolve => { finish = resolve })).mockResolvedValueOnce(report('invalid'))
+    const policy = { ...defaultFileAccessPolicy, request }
+    const view = (fileId: string) => <I18nProvider><FileAccessProvider policy={policy}><ArtifactValidation fileId={fileId}>file</ArtifactValidation></FileAccessProvider></I18nProvider>
+    const { rerender } = render(view('one'))
+    rerender(view('two'))
+    await screen.findByText('File validation failed · repair required')
+    await act(async () => { finish(report('valid')) })
+    expect(screen.queryByText('Format readable · content not verified')).toBeNull()
+    expect(request.mock.calls[0][1].signal.aborted).toBe(true)
+  })
+
+  it('does not request validation for policies without the capability', () => {
+    const request = vi.fn()
+    render(wrap(<ArtifactValidation fileId="one">file</ArtifactValidation>, request, { validationUrl: undefined }))
+    expect(request).not.toHaveBeenCalled()
+    expect(screen.queryByRole('status')).toBeNull()
+  })
+
+  it('uses the public scoped token and strips ambient authorization', async () => {
+    const fetchMock = vi.fn().mockResolvedValue(report('valid'))
+    vi.stubGlobal('fetch', fetchMock)
+    const policy = createPublicFileAccessPolicy('guest-token')
+    render(<I18nProvider><FileAccessProvider policy={policy}><ArtifactValidation fileId="one">file</ArtifactValidation></FileAccessProvider></I18nProvider>)
+    await screen.findByText('Format readable · content not verified')
+    expect(fetchMock.mock.calls[0][0]).toContain('token=guest-token&validation_only=true')
+    expect(fetchMock.mock.calls[0][1].headers.has('Authorization')).toBe(false)
+  })
+
+  it('is wired to inline attachments without requiring a skill or tool trace', async () => {
+    const request = vi.fn().mockResolvedValue(report('unchecked'))
+    render(wrap(<InlineFilePreview source={{ fileId: '123e4567-e89b-12d3-a456-426614174000', filename: 'notes.txt' }} />, request))
+    await screen.findByText('File not checked')
+    expect(screen.getByRole('link')).toHaveTextContent('notes.txt')
+  })
+})

frontend/src/components/file/artifact-validation.tsx

@@ -0,0 +1,90 @@
+import React, { useEffect, useState } from 'react'
+import { useFileAccess } from '@/contexts/file-access-context'
+import { useI18n } from '@/contexts/i18n-context'
+
+type Status = 'valid' | 'invalid' | 'unchecked'
+type DisplayReport = { status: Status; message: string }
+
+async function readReport(response: Response): Promise<DisplayReport> {
+  if (!response.ok) throw new Error('Validation unavailable')
+  // An older backend may ignore validation_only and return the attachment
+  // itself. Never interpret arbitrary JSON file contents as a report.
+  if (response.headers.get('content-type')?.split(';')[0] !== 'application/vnd.xagent.validation+json') {
+    throw new Error('Not a validation response')
+  }
+  const data = await response.json()
+  const statuses = ['valid', 'invalid', 'unchecked']
+  if (!data || !statuses.includes(data.status) ||
+      !Array.isArray(data.checks) || !data.checks.length ||
+      !data.checks.every((c: { status?: unknown } | null) => c && statuses.includes(String(c.status)))) {
+    throw new Error('Invalid report')
+  }
+  if (data.status !== 'unchecked' &&
+      (typeof data.sha256 !== 'string' || !/^[a-f0-9]{64}$/.test(data.sha256))) {
+    throw new Error('Missing snapshot')
+  }
+  if (data.status === 'valid' && !data.checks.every((c: { status: string }) => c.status === 'valid')) {
+    throw new Error('Incomplete checks')
+  }
+  const message = data.checks
+    .filter((c: { status: string; message?: unknown }) => c.status !== 'valid' && typeof c.message === 'string')
+    .map((c: { message: string }) => c.message).join(' ')
+  return { status: data.status, message }
+}
+
+/** Server-authoritative, current-byte checks, independent of preview renderers. */
+export function ArtifactValidation({ fileId, children }: {
+  fileId: string
+  children: React.ReactNode
+}) {
+  const policy = useFileAccess()
+  const { t } = useI18n()
+  const [attempt, setAttempt] = useState(0)
+  const [result, setResult] = useState<DisplayReport & { key: string }>()
+  const url = policy.validationUrl?.(fileId)
+  const key = `${url}:${attempt}`
+
+  useEffect(() => {
+    if (!url) return
+    let active = true
+    const controller = new AbortController()
+    const timeout = setTimeout(() => controller.abort(), 20_000)
+    const check = async () => {
+      try {
+        const response = await policy.request(url, { signal: controller.signal, cache: 'no-store' })
+        const report = await readReport(response)
+        if (active) setResult({ key, ...report })
+      } catch {
+        if (active) setResult({ key, status: 'unchecked', message: '' })
+      } finally {
+        clearTimeout(timeout)
+      }
+    }
+    void check()
+    return () => {
+      active = false
+      clearTimeout(timeout)
+      controller.abort()
+    }
+  }, [key, url, policy])
+
+  if (!url) return <>{children}</>
+  const current = result?.key === key ? result : undefined
+  const label = current?.status ?? 'checking'
+  return (
+    <div data-artifact-validation={label}>
+      <div className="flex items-center gap-2 py-1 text-xs text-muted-foreground" role="status">
+        <span className={label === 'invalid' ? 'text-destructive' : undefined}>
+          {t(`files.validation.${label}`)}
+        </span>
+        {current ? (
+          <button type="button" className="underline" onClick={() => setAttempt(n => n + 1)}>
+            {t('files.validation.recheck')}
+          </button>
+        ) : null}
+      </div>
+      {current?.message ? <p className="text-xs text-muted-foreground">{current.message}</p> : null}
+      <React.Fragment key={key}>{children}</React.Fragment>
+    </div>
+  )
+}

frontend/src/components/file/inline-file-preview.test.tsx

@@ -6,6 +6,12 @@ import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
 const apiRequestMock = vi.hoisted(() => vi.fn())
 const toastErrorMock = vi.hoisted(() => vi.fn())
 
+// Validation has its own server-boundary/integration suite; these tests isolate
+// the existing renderer and streaming contracts from that separate request.
+vi.mock('@/components/file/artifact-validation', () => ({
+  ArtifactValidation: ({ children }: { children: React.ReactNode }) => <>{children}</>,
+}))
+
 vi.mock('@/components/ui/sonner', () => ({
   toast: { error: toastErrorMock },
 }))

frontend/src/components/file/inline-file-preview.tsx

@@ -4,6 +4,7 @@ import { FileText, Loader2, Video, Volume2 } from 'lucide-react'
 import { DocxPreviewRenderer } from '@/components/file/docx-preview-renderer'
 import { ExcelPreviewRenderer } from '@/components/file/excel-preview-renderer'
 import { PptxPreviewRenderer } from '@/components/file/pptx-preview-renderer'
+import { ArtifactValidation } from '@/components/file/artifact-validation'
 import { toast } from '@/components/ui/sonner'
 import { cn, getApiUrl } from '@/lib/utils'
 import { useFileAccess, type FileAccessPolicy } from '@/contexts/file-access-context'
@@ -865,7 +866,19 @@ function ExternalPreviewPlaceholder({
   )
 }
 
-export function InlineFilePreview({
+export function InlineFilePreview(props: InlineFilePreviewProps) {
+  const fileAccess = useFileAccess()
+  const fileId = props.source.fileId && resolveInlineFileId(props.source.fileId)
+  const kind = getInlineFilePreviewKind(props.source)
+  const content = <InlineFilePreviewContent {...props} />
+  // External URLs never enter the authenticated validation boundary. Audio and
+  // video keep progressive delivery; their decoders are not covered yet.
+  if (!fileId || !fileAccess.validationUrl || kind === 'audio' || kind === 'video' ||
+      !getPreviewUrlTrust({ ...props.source, fileId }, getApiUrl()).isTrusted) return content
+  return <ArtifactValidation key={fileId} fileId={fileId}>{content}</ArtifactValidation>
+}
+
+function InlineFilePreviewContent({
   source,
   className,
   imageClassName,

frontend/src/contexts/file-access-context.tsx

@@ -17,6 +17,7 @@ export interface FileAccessPolicy {
   inlineDownloadUrl: (fileId: string) => string
   relativePreviewUrl: (fileId: string, relativePath: string) => string
   pdfPreviewUrl?: (fileId: string) => string
+  validationUrl?: (fileId: string) => string
   /**
    * Execute under this policy's credential boundary. The built-in default
    * attaches Bearer authorization. The public policy forces same-origin
@@ -77,6 +78,7 @@ export const defaultFileAccessPolicy: FileAccessPolicy = {
     return getApiUrl() ? url.toString() : `${url.pathname}${url.search}${url.hash}`
   },
   pdfPreviewUrl: (fileId) => buildUrl(`${FILES_API_PREFIX}/preview-pdf/${encodeFileId(fileId)}`),
+  validationUrl: (fileId) => buildUrl(`${FILES_API_PREFIX}/preview/${encodeFileId(fileId)}?validation_only=true`),
   request: apiRequest,
   listFiles: (query) => {
     const params = new URLSearchParams({ page: "1", size: "20" })
@@ -197,6 +199,7 @@ export function createPublicFileAccessPolicy(accessToken: string): FileAccessPol
     downloadUrl: inlineDownloadUrl,
     inlinePreviewUrl,
     inlineDownloadUrl,
+    validationUrl: (fileId) => `${inlinePreviewUrl(fileId)}&validation_only=true`,
     relativePreviewUrl: (fileId, relativePath) => {
       const url = new URL(
         inlinePreviewUrl(fileId),

frontend/src/i18n/locales/en.ts

@@ -1497,6 +1497,13 @@ Build when you need.`,
       page: "Page {page} of {pages}",
       next: "Next",
     },
+    validation: {
+      checking: "Checking file format…",
+      valid: "Format readable · content not verified",
+      invalid: "File validation failed · repair required",
+      unchecked: "File not checked",
+      recheck: "Recheck",
+    },
     previewDialog: {
       buttons: {
         download: "Download",

frontend/src/i18n/locales/zh.ts

@@ -1497,6 +1497,13 @@ const zh = {
       page: "第 {page} 页，共 {pages} 页",
       next: "下一页",
     },
+    validation: {
+      checking: "正在检查文件格式…",
+      valid: "格式可读 · 内容尚未核验",
+      invalid: "文件校验失败 · 需要修复",
+      unchecked: "文件未校验",
+      recheck: "重新检查",
+    },
     previewDialog: {
       buttons: {
         download: "下载",

frontend/vitest.widget.config.ts

@@ -15,6 +15,7 @@ const widgetConfig = mergeConfig(baseConfig, defineConfig({
         "src/components/file/file-preview-content.tsx",
         "src/components/file/file-viewer.tsx",
         "src/components/file/inline-file-preview.tsx",
+        "src/components/file/artifact-validation.tsx",
         "src/components/file/pptx-preview-renderer.tsx",
         "src/components/task/task-conversation-panel.tsx",
         "src/components/ui/markdown-renderer.tsx",
@@ -116,6 +117,9 @@ const widgetConfig = mergeConfig(baseConfig, defineConfig({
         "src/components/file/inline-file-preview.tsx": {
           statements: 70, branches: 55, functions: 60, lines: 70,
         },
+        "src/components/file/artifact-validation.tsx": {
+          statements: 90, branches: 80, functions: 90, lines: 90,
+        },
         "src/components/file/pptx-preview-renderer.tsx": {
           statements: 45, branches: 35, functions: 30, lines: 45,
         },
@@ -148,6 +152,7 @@ export default defineConfig({
       "src/components/file/file-preview-content.test.tsx",
       "src/components/file/file-viewer.test.tsx",
       "src/components/file/inline-file-preview.test.tsx",
+      "src/components/file/artifact-validation.test.tsx",
       "src/components/file/pptx-preview-renderer.test.tsx",
       "src/components/layout/sidebar.test.tsx",
       "src/components/pages/login.test.tsx",

pyproject.toml

@@ -47,6 +47,7 @@ dependencies = [
   "celery[redis]>=5.4.0,<6.0.0",
   "redis>=5.0.0",
   "pillow >= 10.0.0",
+  "defusedxml>=0.7.1",
   "pypinyin>=0.53.0",
   "cairosvg >= 2.7.1",
   "lancedb>=0.24.2",
@@ -298,9 +299,13 @@ module = [
   "asyncssh",
   "bashlex",
   "docx",
+  "defusedxml",
+  "defusedxml.*",
   "pptx",
   "pptx.*",
   "pdfplumber",
+  "pypdf",
+  "pypdf.*",
   "unstructured.*",
   "fitz",
   "pandas",

src/xagent/config.py

@@ -1811,6 +1811,30 @@ def get_frontend_dist_dir() -> Path:
     return get_web_dir() / "frontend_dist"
 
 
+ARTIFACT_VALIDATION_MAX_BYTES = "XAGENT_ARTIFACT_VALIDATION_MAX_BYTES"
+ARTIFACT_VALIDATION_TIMEOUT_SECONDS = "XAGENT_ARTIFACT_VALIDATION_TIMEOUT_SECONDS"
+
+
+def get_artifact_validation_max_bytes() -> int:
+    """Maximum snapshot bytes to format-check (larger files remain unchecked)."""
+    value = int(os.getenv(ARTIFACT_VALIDATION_MAX_BYTES, str(32 * 1024 * 1024)))
+    if value <= 0:
+        raise ValueError(f"{ARTIFACT_VALIDATION_MAX_BYTES} must be positive")
+    return value
+
+
+def get_artifact_validation_timeout_seconds() -> float:
+    """Hard timeout for each isolated artifact parser process."""
+    import math
+
+    value = float(os.getenv(ARTIFACT_VALIDATION_TIMEOUT_SECONDS, "8"))
+    if not math.isfinite(value) or value <= 0:
+        raise ValueError(
+            f"{ARTIFACT_VALIDATION_TIMEOUT_SECONDS} must be positive and finite"
+        )
+    return value
+
+
 def get_max_upload_size_bytes() -> int:
     """Get the maximum allowed upload size in bytes.
 

src/xagent/core/artifact_validation/__init__.py

@@ -0,0 +1,12 @@
+"""Modular artifact readability checks, independent of skills and agent patterns."""
+
+from .models import ArtifactCheck, ArtifactContent, ValidationLimits, ValidationReport
+from .registry import ArtifactCheckRegistry
+
+__all__ = [
+    "ArtifactCheck",
+    "ArtifactCheckRegistry",
+    "ArtifactContent",
+    "ValidationLimits",
+    "ValidationReport",
+]