DECISION_BRANCH_UNLABELED
DECISION_BRANCH_UNLABELED is a lint warning: a decision diamond with two or more exits has at least one unlabeled exit, so the branch condition is ambiguous.
What triggers it. Adding a second exit to a diamond without a condition label. ISO 5807 / ANSI X3.5 require each exit of a multi-exit decision to be labeled with its condition value.
How to fix it. Label every exit — set_label on the unlabeled edge (e.g. yes/no) or add |condition| to the source line.
Minimal reproducer
This source triggers DECISION_BRANCH_UNLABELED — checked at build time against the same engine the editor runs.
flowchart TD
A{Ready?} -->|yes| B[Ship]
A --> C[Wait]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.