Figma API + MCP vs pen.dev

Figma API + MCP

OpenAPI spec, TypeScript types and an llms.txt index for the REST API. View and Collab seats get 6 MCP calls a month on paid plans.

pen.dev

An agent can create, edit and export .pen designs without a GUI through the pen CLI, with four compact MCP tools that carry annotations and a documented JSON format. The software is closed and needs a pen.dev account. No changelog, status page or security contact was found, and 14 public issue reports had no reply on 8 October 2026.

Figma API + MCP

1. Pass ids= and depth= to GET /v1/files/:key. A whole file is large
2. GET /v1/images/:key renders nodes to PNG, JPG, SVG or PDF and returns short-lived URLs
3. On 429 read Retry-After. Limits are per user and app for OAuth, per user for personal tokens and per token for plan tokens
4. Use the v2 folders endpoints. The v1 projects endpoints were deprecated on 10 August 2026
5. Confirm the credit cost with the user when weave_run_tool returns cost_confirmation_required

pen.dev

1. Call read_skill(), then read_skill({ path: "pen-schema.md" }) and read_skill({ path: "execute.md" }) before the first execute. The tool description alone doesn't document the operations
2. Call get_app_state() and confirm the active document before editing. The MCP server works on whichever .pen file is open in the app
3. In headless pen interactive, call save() before exit(), and keep --in and --out on different paths to preserve the source
4. Check that an export file exists. The docs say an export failure can print an error without a nonzero exit status
5. In CI set PEN_CLI_KEY plus a provider key such as ANTHROPIC_API_KEY. Run pen version, since pen --version is not a flag