| name | lich-python |
| description | Python language adapter. When the target file is .py, maps the ruff rule catalog (~900 rules) into M-engine outputs and contributes Python-specific idiom checks (pyupgrade, typing, async-await patterns). Use when: lich-core fires on a .py file. Do not use for: non-Python files (lich- typescript covers .ts/.tsx; other languages are Phase 2), or as a replacement for ruff itself — this skill maps ruff outputs into Lich's M-engine vocabulary, it does not re-implement ruff.
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| model | haiku |
| tools | ["Read","Bash"] |
lich-python
Preconditions
- Target file extension is
.py.
config/ruff-rule-map.json exists (ships with the adapter; maps ruff rule IDs to M-engine severity + category).- Optional:
ruff is installed in the developer's environment for the richer invocation path. If absent, fall back to Python stdlib ast-based idiom checks using the rule-map's stdlib-feasible subset (~40 of ~120 rules).
Inputs
- Chained from lich-core:
{file: "foo.py", ast_tree: <parsed>}
Steps
- Detect ruff availability. Run
ruff --version via subprocess. Record the version for version-drift detection.
- Invoke ruff (if available).
ruff check --output-format=json <file> — parse the JSON output.
- Fall back (if ruff absent). Run the stdlib-feasible rule subset directly over the
ast_tree from lich-core.
- Map rule IDs to M-engine categories. For each finding, load
config/ruff-rule-map.json and emit:
M1 runtime-failure candidate — if rule is in the "correctness" category (E501 exceptions, F401 unused imports that may cause NameError, etc.)M7 idiom suggestion — if rule is in the "style/idiom" category (UP-series pyupgrade, SIM simplify)skip — if rule is in the "Hydra-overlap" category (CWE-tagged security rules — these belong to Hydra R3)
- Emit findings. Append to
plugins/lich-core/state/review-flags.jsonl under the lich-core sub-plugin's collection point.
Outputs
- Appends to
plugins/lich-core/state/review-flags.jsonl.
- Return value:
{ruff_version: "...", rules_fired: N, skipped_hydra_overlap: N}.
Handoff
Findings flow back through lich-core → lich-sandbox (for M1-class flags) → lich-rubric → lich-verdict.
Failure modes
- F14 version drift — ruff's JSON output format changes; the adapter must pin a tested range and warn on mismatch.
- F04 task drift — re-implementing ruff rules in the adapter. Don't. The adapter maps; ruff does the work.
- F07 over-helpful substitution — running ruff with
--fix and auto-rewriting code. Never. Lich is advisory.
Why Haiku tier
This skill is a thin mapping layer: invoke subprocess, parse JSON, lookup in rule-map, emit. No reasoning. Haiku is appropriate.
