wehub-resource-synckarpathy-coder
Active coding discipline enforcer based on Andrej Karpathy's observations on LLM coding pitfalls.
Not just guidelines — ships Python tools that detect violations, a review agent, a slash command, and a pre-commit hook.
The 4 principles
| # | Principle | What it prevents | Tool that checks it |
|---|---|---|---|
| 1 | Think Before Coding | Hidden assumptions, silent choices | assumption_linter.py |
| 2 | Simplicity First | Over-engineering, premature abstractions | complexity_checker.py |
| 3 | Surgical Changes | Diff noise, drive-by refactors | diff_surgeon.py |
| 4 | Goal-Driven Execution | Vague plans, missing verification | goal_verifier.py |
Quick start
# Install as Claude Code plugin
/plugin marketplace add alirezarezvani/claude-skills
/plugin install karpathy-coder@claude-code-skills
# Run before committing
/karpathy-check
# Or use individual tools from the shell
python scripts/complexity_checker.py src/ --threshold strict
python scripts/diff_surgeon.py --diff HEAD~1..HEAD
echo "I'll just export all user data" | python scripts/assumption_linter.py -
python scripts/goal_verifier.py plan.md
What's in the box
| Piece | Count | Detail |
|---|---|---|
| SKILL.md | 1 | The 4 principles with context: fork for skill chaining |
| Python tools | 4 | complexity_checker, diff_surgeon, assumption_linter, goal_verifier — all stdlib-only |
| Sub-agent | 1 | karpathy-reviewer — runs all 4 principles against a diff |
| Slash command | 1 | /karpathy-check — one-command pre-commit review |
| Pre-commit hook | 1 | karpathy-gate.sh — non-blocking awareness gate |
| Reference docs | 3 | Full Karpathy context, 10+ anti-pattern examples, 4-level enforcement guide |
The tools
complexity_checker.py (Principle #2)
Detects over-engineering: cyclomatic complexity, class density, nesting depth, function length, premature ABC/Protocol usage, import coupling.
python scripts/complexity_checker.py src/auth/ --threshold strict --json
# → score 72/100, 3 findings: nesting depth 6, function 'validate' 62 lines, 2 classes in 80 lines
Three threshold levels: strict (new code), medium (default), relaxed (legacy).
diff_surgeon.py (Principle #3)
Analyzes a git diff and flags lines that don't trace to the stated goal: comment-only changes, whitespace noise, style drift (quote swaps), drive-by refactors, docstring additions to unchanged functions.
python scripts/diff_surgeon.py # staged changes
python scripts/diff_surgeon.py --diff HEAD~3..HEAD # last 3 commits
# → Noise ratio: 23% (NOISY), 7 comment-only changes, 2 quote-style swaps
assumption_linter.py (Principle #1)
Reads a plan or proposal and flags hidden assumptions: "just" (hides complexity), "obviously" (unstated assumption), "should work" (hopeful, not verified), vague action verbs, unscoped user references, missing format specifications.
echo "I'll just add a function to export all user data" | python scripts/assumption_linter.py -
# → 3 findings: assumption-just, missing-format, scope-absolute
goal_verifier.py (Principle #4)
Scores each step of a plan for verification quality (0-3 per step). Flags vague criteria ("should work"), checks for final end-to-end verification, and recommends concrete checks.
python scripts/goal_verifier.py implementation-plan.md --json
# → 6 steps, 8/18 (44%), WEAK — 3 steps have no verification
Enforcement levels
- Passive — install plugin, principles load as context (~60% compliance)
- Active review — run
/karpathy-checkbefore commits (~85%) - Pre-commit hook — wire
karpathy-gate.shvia Husky (~95%) - CI gate — add tools to GitHub Actions PR checks (~99%)
See references/enforcement-patterns.md for setup instructions at each level.
Cross-tool compatibility
The tools are pure Python stdlib. The principles work in any AGENTS.md-aware CLI (Codex, Cursor, Antigravity, OpenCode, Gemini CLI).
Attribution
Derived from Andrej Karpathy's X post on LLM coding pitfalls. The principles are Karpathy's observations; the tooling, enforcement patterns, and anti-pattern gallery are original.
License
MIT.