---
issue: 52
issue_title: "Bash command arity table for smart approval pattern suggestions"
---

# Retro: #52 — Bash command arity table for smart approval pattern suggestions

## Final Retrospective (2026-05-04T22:35:00-04:00)

### Session summary

Planned and implemented a curated arity dictionary (`src/bash-arity.ts`) that replaces the naive first-word heuristic in `suggestBashPattern()` with longest-match-wins prefix lookup.
Four TDD steps executed cleanly with one minor downstream test fix.
Released as v4.7.0.

### Observations

#### What went well

- Plan-to-implementation was a straight line — the design overview worked through edge cases (single-token, arity-covers-all-tokens, trailing wildcard vs space wildcard) thoroughly enough that zero design decisions were needed at coding time.
- Downstream test breakage in `tests/handlers/tool-call.test.ts` was caught by the full-suite run after step 3, fixed in the same commit (amend), exactly per AGENTS.md guidance.
- The issue's scope was tight and self-contained — no dependency conflicts, no config format changes, no breaking changes.

#### What caused friction (agent side)

- No significant friction points this session.

#### What caused friction (user side)

- No significant friction points this session.

### Changes made

1. `docs/retro/0052-bash-arity-table.md` — this file.