Whiteboard by Lumin

What you can ask

• Create a whiteboard and save it with this chat.Copy

  Example path open_board · whiteboard skill

• Refine the diagram on my open whiteboard.
• Turn this explanation into a simple flowchart.

MCP connector

Server URL

https://lumininnovates.com/mcpCopy

Login

None

Protocol

MCP 2025-11-25

Instructions

Whiteboard is a local-file editor for Codex desktop. The hosted service supplies only the editor, never board storage. Create a new board only when requested. Create an ordinary .excalidraw JSON file in the current chat workspace's outputs directory (or the user's requested location), with a unique filename. The minimal document is {"type":"excalidraw","version":2,"source":"whiteboard","elements":[],"appState":{"viewBackgroundColor":"#ffffff"},"files":{}}. Open that exact local file using the host's supported file-opening tool. The installed Whiteboard file handler opens it. Do not pass local paths or document contents to this remote server. open_file is an app-only entrypoint invoked by the host with an opaque resource URI, not by the model. To refine the visible board, use its file name and context to resolve the SAME file in the current workspace. Read the latest file before every edit, preserve unrelated shapes, embedded images, and appState. Reuse element IDs, increment changed native elements' version and versionNonce. Apply small steps to that file so the open canvas updates progressively. Do not reopen the editor or create another file after editing. Stop if manual edits are unsaved or the file changed since reading; reread and merge rather than overwriting. Only claim saved after the filesystem write succeeds. Give the user a clickable file link. Saving a chat alone is not a file backup; the board remains in its workspace until the user deletes or moves it. No account or cloud storage is required. Mobile and hosts without local resource APIs support manual .excalidraw import and download, not automatic chat-local persistence.

Tools

Skills

4 in the ChatGPT listing

• whiteboardOperate Whiteboard by Lumin to create, open, save, and edit local .excalidraw files in a Codex chat.
• Whiteboard layoutArrange and tidy diagrams on Whiteboard by Lumin with readable spacing, alignment, groups, and connectors.
• Whiteboard storytellingTurn an explanation, process, comparison, or idea into a visual story on Whiteboard by Lumin.
• Whiteboard styleStyle Whiteboard by Lumin drawings with Excalidraw's handwritten Excalifont, readable text, restrained color, and consistent strokes.