Render saved screenshots and recordings in chat markdown

[juliusmarminge]

Summary

• Add secure asset access for saved screenshots, videos, and browser artifacts.
• Support saving preview screenshots to workspace paths or browser artifact storage.
• Render saved media directly in chat markdown.
• Extend preview recording and snapshot contracts and handlers.
• Tighten pull request head matching and simplify related UI logic.

Testing

• Added focused coverage for asset URL issuance and browser artifact validation.
• Added MCP snapshot save-path and artifact persistence tests.
• Not run: lint and test commands were not provided.

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Note

Medium Risk
New filesystem write paths and asset signing for browser artifacts add security-sensitive surface area, though workspace saves include extensive symlink/traversal guards and tests.

Overview
Agents can persist preview snapshots via preview_snapshot with save (writes to browserArtifactsDir) or savePath (workspace-relative .png), with symlink-safe containment checks on workspace writes; results include savedScreenshotPath for embedding in replies.

The asset API gains a browser-artifact resource backed by <stateDir>/browser-artifacts, with issuance limited to media file names (no traversal). Workspace videos (.webm, .mp4, etc.) use exact-file signed URLs like images.

Chat markdown renders img/video through MarkdownMedia, resolving workspace paths and absolute browser-artifacts paths to signed URLs; sanitization allows video tags and preserves Windows drive-letter src values.

Preview tool descriptions document embedding recordings and screenshots in chat.

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Note

Render saved screenshots and recordings in chat markdown

• Adds save and savePath parameters to the preview_snapshot MCP tool: savePath writes a PNG to a workspace-relative path with symlink/traversal protection; save=true writes to a server-side browser artifacts directory with a timestamp+UUID filename.
• Introduces a new browser-artifact asset claim type in assets.ts, allowing the server to issue and resolve signed URLs for files in browserArtifactsDir by filename only.
• Adds a MarkdownMedia.tsx component that resolves img and video tags in chat markdown from direct URLs, workspace-relative signed URLs, or browser artifact filenames, with loading/error states and image expansion.
• Extends chat markdown sanitization in ChatMarkdown.tsx to allow video tags and adds a rehype plugin to preserve Windows drive-letter paths through sanitization.
• Risk: the new browser-artifact claim resolves files by filename from a server directory; invalid or missing filenames return null rather than an error to the client.

^{Macroscope summarized a035fa0.}

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✨ Finishing Touches

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[macroscopeapp]

Effect service review: one convention issue found regarding error cause preservation. See inline comment.

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[macroscopeapp]

Approvability

Verdict: Needs human review

New feature introducing browser artifact handling, media rendering in chat, and screenshot-saving capabilities across server and web packages. The scope includes new asset types, new UI components, and security-sensitive path resolution logic that warrants human review.

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[cursor]

Cursor Bugbot has reviewed your changes using high effort and found 1 potential issue.

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