OFF_CANVAS
OFF_CANVAS is a structural error: a positioned node extends past the computed canvas on the reported axis.
What triggers it. Never in normal operation — the engine sizes the canvas around content, so this is a tripwire that fires only when a layout pass moves geometry after the canvas was sized. Layout is deterministic, so a firing input reproduces byte-identically.
How to fix it. Not fixable by editing the diagram content itself: simplify or remove the construct that provokes it, and report the source as a renderer bug so the layout defect gets fixed.
Run am verify diagram.mmd --json, inspect this code, and apply the smallest source or typed mutation that clears it. If it persists after two mechanical attempts, return the warning and ask for human review.
In the cloned repo, am is bun run bin/am.ts.
Back to all warning codes, or open the editor to watch this warning clear as you edit.