12. Known limitations

Collected from the code, from its comments, and from driving the app. Nothing here is a plan; it is what the thing does not do today.

Rendering and export#

PDF artwork is a raster. Page geometry is vector-exact (media box in points, multi-page splitting, A4 tiling), but the artwork is a JPEG at 200 dpi by default, so PDF text is not selectable or searchable and deep zooms show pixels. This is deliberate: the PDF is rasterised from the exporter's own SVG so the two can never look different. dpi: 300 is the print setting.
SVG, PNG, draw.io and Mermaid are per page. Only Plota JSON and PDF cover a whole multi-page document in one file; exporting the others with scope All pages writes one file per page.
Mermaid export is a flowchart projection (a sequence diagram exports as sequenceDiagram). Shape kinds collapse to the handful of Mermaid node shapes; styling, layers, data and pages are dropped.
A document theme change rewrites the theme's style keys. Per-node overrides survive, but there is no per-page theme.

A foreign SVG becomes one image node. Only SVGs this app wrote are re-read as a real document. The importer says which one you got.
Mermaid import covers 13 diagram types (see Mermaid diagrams). Charts and grids — gantt, pie, quadrantChart, xychart, sankey, packet, kanban, radar-beta, treemap-beta — and zenuml are refused by name.
Icons and service tiles from captions are an MCP-server feature. A Mermaid chart pasted into the editor keeps plain shapes; add icons from the Icons panel.
The PlantUML reader is a deliberately small subset: declarations (participant, actor, class, component, database, entity, usecase, …), the arrow spellings, [*] terminals and title. Skinparams, notes, packages and nested blocks are ignored.
Lucidchart import reads the clipboard's text/html flavour, not .lucid files. Unknown block classes fall back to a plain rectangle rather than dropping the paste.
draw.io shapes outside the mapped style vocabulary become rectangles. The warning list in the import dialog names what was approximated.

Smart Route plans orthogonal and Smart connectors with both ends on a shape and no hand-placed waypoints together. Elbow, straight, curved, waypointed and free-ended connectors are drawn one at a time, so they are not spread along a shape's side or kept apart from their neighbours.
On very large pages routing is the slowest part of redrawing; turn Smart Route off while you rearrange, or set the busiest connectors to elbow.
Keeping parallel runs apart is best-effort. Where there is no room, two connectors can still share a run.

Auto-fit does not apply to containers and renderer-driven kinds: plane, group, fragment, lane, lifeline, activation and image are skipped and reported as skipped, because sizing them from their own label would collapse them over their children.
ERD attribute rows are drawn by the ERD stencil, not the shared label renderer. The shared renderer treats a newline as ordinary whitespace and re-wraps the body into a centred block, which cannot line an attribute up with its divider. Consequence: inline markup (**bold**, links, …) does not apply inside attribute lines — only in the entity name.
The same is true of the other content-driven stencils (table, umlClass): their body text is a model, not prose.

No autosave, no server, no accounts, no collaboration. Ctrl/⌘ S writes to localStorage; clearing site data deletes it. Export JSON for anything that matters.
WebLLM needs WebGPU and a one-off download of roughly 1.5 GB. Without WebGPU the panel says so and downloads nothing.
Embeddings need the model CDN on first use (~23 MB, then cached). Offline the semantic features degrade to lexical similarity and say so.
Ollama cannot be reached from a file:// page — there is no origin to put in OLLAMA_ORIGINS. Serve the single-file build over http:// if you want a local model with it.
The single-file build stubs the three heavy in-browser models — WebLLM, transformers.js (embeddings) and background removal — because inlining them would add gigabytes. It does not stub the network providers: Ollama and any OpenAI-compatible server work normally, since they are plain fetch calls. Serve the file over http:// rather than opening it as file://, or the browser sends a null origin that Ollama's CORS check rejects.
A model can produce a valid but wrong plan. The op schema is enforced, so it cannot corrupt the document, but it can still propose nonsense — which is why nothing is applied without a preview.