cursor-design

Agent-driven live HTML artboard for Cursor - Claude Design–style canvas without in-panel chat.

• Panel: Webview artboard (host chrome + sandboxed HTML iframe)

• Brain: Cursor Agent (your subscription) via local MCP + disk under .cursor-design/

• Not: a Next.js app, Chrome extension, or in-extension LLM calls

Status

v0.1.0: installable .vsix with an artboard panel, seven MCP tools, export handoff + stale badge, and documented v1 limits.

Spec (source of truth): Notion - Cursor Design

Related MCP server: figsnap-mcp

MCP tools

Server name: cursor-design. Tools:

• set_artboard - create a new artboard id (html required; empty string allowed)

• update_artboard - replace HTML; requires baseGeneration and/or baseHash

• read_artboard - HTML + meta; artboardId optional (defaults to active)

• list_artboards - ids on disk (no HTML bodies)

• set_active_artboard - switch the active id (does not open the panel)

• export_artboard - write .cursor-design/handoff/<exportId>/ and record lastExport (call before implementing)

• handoff_status - { stale, activeArtboardId, activeHash, lastExport? }; re-export when stale is true

Allowlist the server if Cursor prompts. If MCP is denied, edit .cursor-design/** on disk and tell the user to allowlist the tools.

Install

1. From this repo: pnpm vsix writes cursor-design-0.1.0.vsix at the repo root.

2. In Cursor: Command Palette → Extensions: Install from VSIX… → pick that file → reload.

3. Open a trusted folder. Command Palette → Cursor Design: Open Artboard.

4. Settings → MCP: allowlist cursor-design (toggle off/on if the tool count stays 0; see Limits).

Smoke-tested 2026-09-13, Cursor 3.20.17.

Develop

pnpm install
pnpm compile

Confirm dist/mcp.js exists after compile or the watch/preLaunchTask build. F5 will not register a working stdio server without it.

In Cursor: open this folder → F5 (Run Extension). The Extension Development Host opens fixtures/dev-workspace (positional folder arg in .vscode/launch.json). The panel does not open on startup.

Then in the Extension Development Host window (not this repo window):

1. Command Palette → Cursor Design: Open Artboard - chrome + disk preview, no CSP errors in the webview console.

2. Check MCP: Settings → MCP. Server name cursor-design. Activation is onStartupFinished, so it registers without opening the panel.

3. Allowlist cursor-design (toggle off/on if the tool count stays 0).

Commands:

• Cursor Design: Open Artboard - open/reveal the panel

• Cursor Design: Reveal Design Folder - reveal .cursor-design/ if it exists (does not create it)

• Cursor Design: Export Handoff - export the active artboard to .cursor-design/handoff/<exportId>/

Output: View → Output → Cursor Design.

Agent entry: AGENTS.md

Workflow overlay: AI Blueprint (plans and review gates, not the product stack).

Export to implement trial

F5 in the Extension Development Host with fixtures/dev-workspace open:

1. Command Palette → Cursor Design: Open Artboard. No handoff badge.

2. Design a hero + CTA on the active artboard via Cursor Agent (set_artboard / update_artboard).

3. Call export_artboard (or Command Palette → Cursor Design: Export Handoff). Confirm .cursor-design/handoff/<exportId>/{index.html,IMPLEMENT.md,tokens.json} and manifest.json lastExport. Badge still hidden.

4. In a second Agent session, open .cursor-design/handoff/<exportId>/IMPLEMENT.md (from manifest.json.lastExport.exportId) and implement into fixtures/dev-workspace/sample-app/index.html. Do not copy .cursor-design/ into the app.

5. Edit artboards/<id>.html and save. Within ~200ms the panel badge shows Handoff out of date. Re-export.

6. Re-export. Badge clears. The previous handoff directory stays on disk.

Then cd fixtures/dev-workspace/sample-app && pnpm install --ignore-workspace && pnpm dev to view the implemented page. (--ignore-workspace is required because this repo has a root pnpm-workspace.yaml; without it, pnpm install no-ops and vite is missing.) Observed 2026-09-12: Vite 8.3.0 served index.html at http://localhost:5173/ (Implement the exported artboard here.).

Trial performed: 2026-09-12 (live F5 pass, steps 2–6 green; 6 handoffs on disk, stale:false, Vite 200 with latest implement).

Limits (v1)

Facts, not a roadmap. Drift vs the rules or overview is labeled.

• Cursor only: MCP registration uses vscode.cursor.mcp.registerServer. In plain VS Code the server is not registered (warning in Output → Cursor Design); the panel still renders .cursor-design/ from disk, with no Agent loop.

• First workspace folder only; multi-root beyond the first folder is ignored (revealDesignFolder.ts, handleOpenArtboard.ts ponytail).

• Untrusted workspaces unsupported (capabilities.untrustedWorkspaces.supported: false); artboard HTML is executable workspace content.

• One active artboard, no gallery; variants are new ids + set_active_artboard.

• Writes: one process-wide MCP queue (recorded drift vs rule 02 "Serialize writes per artboard id"; documented as-is, queue unchanged); host-vs-MCP manifest writes are last-writer-wins; no cross-window lock (mcpQueue.ts, watchArtboardDisk.ts, artboardFs.ts ponytails). Failed multi-file writes leave partial files (no journal/rollback); orphan handoff dirs are never deleted.

• Artboard iframe: sandbox="allow-scripts". CSP blocks inline event handlers, style="" attributes, and external subresources in the artboard (artboardChromeHtml.ts v1 limit).

• Handoff carries the whole document in index.html (no CSS/JS split; recorded Phase 3 lock vs overview "HTML+CSS+JS"); .cursor-design/assets/ is copied manually; tokens.json is passed through without validation.

• Brain is Cursor Agent only: no in-panel chat, no model API keys, no vscode.lm.

• Not on the Marketplace; install from .vsix (Extensions: Install from VSIX…).

• Cursor MCP settings may show 0 tools until the server is toggled off/on.

• Chrome is vanilla nonce'd script, not the Svelte 5 + Vite chrome named in the overview (recorded drift, not fixed here).

License

MIT - see LICENSE.