lich-typescript

name	lich-typescript
description	TypeScript / JavaScript language adapter. When target file is .ts, .tsx, .js, or .jsx, invokes biome (if installed) or tsc --noEmit (substrate fallback), maps findings into M-engine outputs, and contributes TS- specific idiom checks (React hooks deps, JSX a11y, narrow-type-guards). Use when: lich-core fires on a TypeScript/JavaScript file. Do not use for: non-TS/JS files; replacing biome; auto-fix mode (Lich is advisory).
model	haiku
tools	["Read","Bash"]

lich-typescript

Preconditions

• Target file extension is .ts, .tsx, .js, .jsx, or .mjs.
• config/biome-rule-map.json exists.
• One of these is available in the repo: biome binary, tsc --noEmit via local typescript devDep, or the Lich fallback (minimal regex-based idiom checks — last resort).

Inputs

• Chained from lich-core: {file: "Foo.tsx", substrate_status: "ok"|"parse-failed"}

Steps

1. Detect biome availability. Try biome --version. If present, invoke biome check --json --reporter=json <file>.
2. Fall back to tsc --noEmit if biome absent but TypeScript is installed. Parse diagnostic output.
3. Final fallback: stdlib. If neither biome nor tsc is available, run the regex-based idiom subset (~20 rules) and flag substrate: fallback-regex in the output — honest about reduced coverage.
4. Map rule IDs to M-engine categories. From config/biome-rule-map.json:
   • M1 runtime-failure candidate — correctness rules (no-unused-vars, no-undef, strict-null-checks violations)
   • M7 idiom suggestion — style rules (useExhaustiveDependencies, useArrowFunction, useConst)
   • skip — Hydra-overlap rules (noSecrets, noEval, noUnsafeOptionalChaining with security framing)
5. Emit findings. Append to plugins/lich-core/state/review-flags.jsonl.

Outputs

• Appends to plugins/lich-core/state/review-flags.jsonl.
• Return: {substrate: "biome"|"tsc"|"fallback-regex", rules_fired: N, skipped_hydra_overlap: N}.

Handoff

Findings flow through the standard lich pipeline: lich-core → lich-sandbox (M1-class) → lich-rubric → lich-verdict.

Failure modes

• F14 version drift — biome JSON output or tsc diagnostic format changes. Pin tested version range; warn on mismatch.
• F04 task drift — re-implementing biome rules. Don't; the adapter maps, biome does the work.
• F07 over-helpful substitution — biome check --apply. Never. Lich is advisory.
• F13 distractor pollution — on a 10k-line file, biome may emit hundreds of findings; filter to changed hunks (from Crow's change classification) before mapping.

Why Haiku tier

Thin mapping layer — invoke subprocess, parse JSON, lookup, emit. No reasoning.