LABEL_OVERFLOW
LABEL_OVERFLOW is a structural warning: a label’s longest rendered line exceeds the character cap (default 40), which hurts layout and readability. The count measures what the renderer draws: `<br>` starts a new line, XML entities like ` ` count as one character, and formatting tags are stripped.
What triggers it. Prose sentences pasted into node labels, edge labels, message text, or section/period titles — common when an agent copies requirement text verbatim into the diagram. Multi-line labels fire only when a single rendered line exceeds the cap.
How to fix it. Shorten the text with set_label, set_message_text, or the matching family mutation; raise labelCharCap in VerifyOptions only when long labels are genuinely intended.
Minimal reproducer
This source triggers LABEL_OVERFLOW — checked at build time against the same engine the editor runs.
flowchart LR
A[This label is far longer than the forty character cap] --> B[Done]Open this reproducer in the editor
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.
Machine-readable: this page as Markdown.
Back to all warning codes, or open a blank editor to try a fix.