Excalidraw Architect

Overview

Generate structured architecture diagrams in Excalidraw by scripting scene elements (rectangles, text, arrows) through the page runtime API, then iterating quickly based on user feedback.

Workflow

1) Open and verify the Excalidraw tab

Open https://excalidraw.com/ in the browser tool and keep using the same targetId for all edits.

If the user already has a board open, reuse that tab instead of creating a new one.

2) Get Excalidraw runtime API from the page

Use an evaluate action to locate excalidrawAPI from the React fiber tree.

If API lookup fails, refresh once and retry.

Use this lookup logic (or equivalent):

• find .excalidraw root
• read __reactFiber$*
• traverse child/sibling fibers
• pick node where memoizedProps.excalidrawAPI.updateScene exists

3) Build scene elements from the requested architecture

Translate the user’s request into:

• container blocks (rectangles)
• section labels and body text
• directional arrows between blocks

Prefer clear readable layout:

• title at top
• left-to-right data flow unless user requests otherwise
• enough spacing to avoid overlap

4) Write scene to canvas

Call api.updateScene({ elements, appState }) and then api.scrollToContent(elements, { fitToContent: true }).

When user requests changes, rewrite the scene deterministically (do not partially patch random elements unless user asks for tiny edits).

5) Confirm result

Send a short completion message and mention what changed.

Editing Rules

• Preserve user’s scope boundaries (example: “only draw to Raw Data Pool”).
• Keep language concise and business-readable.
• Prefer complete labels over abbreviations.
• If text is too dense, split into multiple lines.
• If user asks for “only one layer”, remove downstream blocks explicitly.

Reusable Resources

scripts/

• scripts/generate_excalidraw_scene.py: convert a JSON spec into Excalidraw element JSON.

references/

• references/excalidraw-api-snippets.md: tested API discovery and update snippets for browser evaluate calls.

Use scripts/resources when diagrams are large or need repeatable generation.