Issue

---
description: Work an issue from open to done — implement, test, run all gates, close.
argument-hint: <issue description or number>
---

Work the following issue to completion: $ARGUMENTS

Follow this sequence exactly:

1. **Understand** — read the relevant code in `stretch`. Identify which crate(s) are affected.
2. **Plan** — write a 3-5 bullet implementation plan. Ask if unclear.
3. **Implement** — make the change. Follow CLAUDE.md coding rules exactly.
4. **Test** — write tests that would catch the bug or validate the feature. Target 0 mutant survivors on changed lines.
5. **Gate** — run `/gate`. Do not declare done until all 5 gates pass.
6. **Done** — summarize what changed and what the 5 gate results were.

Do NOT declare an issue complete if `cargo mutants` shows survivors on changed `src/` files.