my-pi/pi-permission-system/docs/retro/0052-bash-arity-table.md

issue, issue_title

issue	issue_title
52	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.