| name | edit-deterministic |
| description | Offload mechanical and type-aware edits to deterministic tools instead of LLM file-rewrites (P2). Use ast-grep --rewrite for repeated/mechanical transforms and Serena replace_symbol for single type-aware symbol edits. Apply whenever a change is rule-shaped rather than judgment-shaped. |
Deterministic Edit Skill (P2)
Purpose
Minimize LLM file-rewrites. If an edit follows a rule, a tool should apply it — verifiably and reversibly (invariant: cheap to verify, cheap to roll back).
Decision
- Mechanical / repeated across many sites →
ast-grep --rewrite (preview first).
- Single, type-aware symbol (rename/replace a function/method body) → Serena
replace_symbol.
- Genuine judgment (novel logic, one-off) → LLM
Edit, smallest diff, match surrounding code.
ast-grep --rewrite (mechanical)
ast-grep -p 'foo($A)' --rewrite 'bar($A)' --lang ts
ast-grep -p 'foo($A)' --rewrite 'bar($A)' --lang ts -U
Serena (type-aware, single symbol)
find_symbol → locate the exact symbol (no whole-file read).replace_symbol_body → swap one definition, LSP-aware.- Single MCP; use only when enabled. Absent → fall back to scoped
Edit.
- Large repos:
serena project index first; turn it off for tiny modules (startup cost).
- Kotlin escape hatch (ADR-005) — Serena's standard LSP can be flaky on Kotlin (slow startup). For deep Kotlin/Spring symbol work, the IntelliJ/JetBrains backend is the gold standard; switch to it only when the standard LSP misbehaves (it's paid + IDE-bound, so not the default).
- Verified findings worth keeping go to
.serena/memories (human-reviewed, P5) — not auto-injected.
Rules
- Preview every
--rewrite before applying; commit boundary around it (P6).
- Re-confirm target in one shot before a multi-site change (P3), then verify (
scripts/verify.sh).
- Optional tools may be absent — degrade to a minimal manual
Edit, never block.
Need rewrite/replace patterns and worked examples? Read references/patterns.md.
