pre-commit-review

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pre-commit-review is a reusable skill package for reviewing Git diffs before committing, pushing, or opening a pull request.

It is designed for agent workflows such as Codex- or Claude-style skill systems, where you want a structured, repeatable pre-commit quality gate instead of an ad hoc diff summary.

Available Languages

• English: README.md
• Simplified Chinese: README.zh-CN.md

Translations should stay functionally aligned. If you update one version, update the others in the same change when possible.

What It Does

• Reviews the most relevant diff source in priority order:
  • user-provided diff
  • staged changes
  • unstaged changes
  • branch vs. base branch
• Produces a consistent review format focused on:
  • what changed
  • code quality issues
  • intent
  • logic shifts
  • blast radius
  • regression risk
  • performance & cost impact (only on hot paths, queries, loops, or network/IO calls)
• Returns a clear verdict:
  • SAFE_TO_COMMIT
  • SAFE_TO_COMMIT_WITH_NOTES
  • DO_NOT_COMMIT
• Uses a read-only helper script to collect local Git context without mutating the repository

Why This Repository Exists

This repository is not an application or framework. It is a small, portable skill package that can be:

• published as a standalone open source repository
• copied into an existing skills collection
• adapted for local agent tooling that needs pre-commit review behavior

Repository Structure

.
├── install.sh
├── SKILL.md
├── agents/
│   └── openai.yaml
├── collect-diff-context-cli/
│   ├── Cargo.toml
│   └── src/
├── docs/
│   └── superpowers/
├── references/
├── scripts/
│   ├── bin/
│   ├── build_all_binaries.sh
│   ├── build_with_docker.sh
│   ├── collect_diff_context.sh
│   ├── collect_diff_context.legacy.sh
│   └── validate_schemas.py
├── tests/
│   ├── lib/
│   ├── collect_diff_context_test.sh
│   ├── full_review_workflow_test.sh
│   ├── helper_shadow_mode_test.sh
│   ├── install_agent_matrix_test.sh
│   ├── install_smoke_test.sh
│   ├── parity_assets_test.sh
│   ├── parity_golden_test.sh
│   └── skill_contract_test.sh
└── evals/
    ├── output/
    ├── taxonomy/
    ├── eval_contract_test.sh
    ├── readme_surface_test.sh
    ├── readme_host_entrypoints_test.sh
    ├── output-eval.json
    ├── trigger-eval.json
    ├── output_eval_runner.sh
    ├── output_eval_runner_test.sh
    ├── output_eval_codex_runner.sh
    ├── output_eval_claude_runner.sh
    ├── output_eval_codex_case.sh
    ├── output_eval_claude_case.sh
    └── output_eval_host_wrappers_test.sh

references/

Loaded on demand by SKILL.md. References are now layered by responsibility:

Layer	Files	Loaded when	Purpose
decision/	verdict-rules.md, risk-taxonomy.md	Every routine review	Verdict selection, blocker thresholds, finding markers, tally rules, and evidence discipline
rendering/	output-en.md, output-zh.md, visual-output.md, review-meta.md	When rendering the response	Per-language review skeletons, optional visual presentation guidance, and machine-readable metadata
advanced/	coverage-led-review.md, visual-review-rules.md, grading-compat.md	Only for complex workflows	Coverage-led review flow, UI/visual review rules, and grading-sensitive exact phrases
examples/	default-tiny-en.md, default-tiny-zh.md, complex-visual-and-coverage.md	Optional calibration only	Concrete examples for aligning structure and tone without redefining the rules

Daily Default/Tiny reviews intentionally avoid loading the examples/ layer unless structure calibration is needed, which keeps routine runs small and stable.

SKILL.md

Defines the skill itself:

• when it should be triggered
• how the diff source is resolved
• how large diffs are handled
• what review dimensions must be covered
• the required output template and verdict rules

scripts/collect_diff_context.sh

A read-only helper script that gathers local repository context for the review workflow. It:

• detects whether the current directory is a Git repository
• prefers staged changes when present
• falls back to unstaged changes or branch-vs-base comparison
• reports diff stats, file lists, and status
• identifies truncation, path/content high-risk candidates, generated-like files, lock files, and top-churn files
• emits a Review Manifest and Review Groups for coverage-led commit-readiness workflows
• records rename, delete, binary, mode-only, and submodule pointer changes as manifest units
• emits Review Plan JSON for reducer-friendly automation without Markdown table parsing
• emits Split Suggestions for review groups that exceed the hard budget
• emits Split Unit Diff Preview blocks for hunk-level review
• emits a Coverage Ledger Template with pending review units
• emits Group Review Result templates for reducer-ready group findings
• emits a Reducer State Snapshot Template for long multi-step reviews
• emits a Coverage Validation Checklist for reducer preflight
• emits a Full Review Execution Plan with ordered split/review steps
• emits Group Review Work Packets for serial or delegated group review
• emits a Reducer Finalization Template for final synthesis gates
• emits a best-effort Dependency Summary for cross-file reduction
• emits bounded Semantic Context Queries from project-provided read-only grep patterns
• emits a suggested review queue for large or truncated diffs
• truncates oversized diffs safely when needed

It does not fetch, stage, reset, install, or modify files.

The default diff output budget is 200KB. Override it with PRE_COMMIT_REVIEW_MAX_DIFF_BYTES; use a lower value when the surrounding conversation is already large, and use 0 only when printing the full diff is safe.

Review group budgets default to 120KB target and 160KB hard limit. Override them with PRE_COMMIT_REVIEW_GROUP_TARGET_BYTES and PRE_COMMIT_REVIEW_GROUP_HARD_BYTES; groups over the hard limit are marked split-required.

Rollout and Multi-Implementation Controls

The entrypoint wrapper scripts/collect_diff_context.sh supports multiple execution modes for transition and safety:

• PRE_COMMIT_REVIEW_HELPER_IMPL: Specifies the helper implementation mode.
  • rust (default): Executes the compiled Rust CLI binary. If it fails, prints a warning to stderr and gracefully falls back to the legacy script collect_diff_context.legacy.sh.
  • legacy or shell: Forces execution of the legacy Shell script.
  • shadow: Runs both the legacy Shell script and the Rust binary, compares their stdout, logs any differences to /tmp/collect_diff_context_shadow_diff.log, and returns the legacy script's stdout to ensure safety.
• PRE_COMMIT_REVIEW_SHADOW_MODE: If set to 1, forces Shadow Mode comparison even when PRE_COMMIT_REVIEW_HELPER_IMPL is explicitly set to legacy or shell.
• PRE_COMMIT_REVIEW_DISABLE_FALLBACK: If set to 1, disables the legacy script fallback, strictly propagating Rust CLI process failures.

Use scripts/collect_diff_context.sh --source <staged|unstaged|branch> --group <group_id> to retrieve one in-budget review group's diff after a global diff is truncated. Use --path <path> for file-level follow-up when a group needs narrower context or has been split. Helper-emitted context_command values include --source so follow-up retrieval stays pinned to the original diff source; split-required groups must be reviewed through split suggestions instead of as one group.

Project-specific risk hints can live in .pre-commit-review/risk-paths and .pre-commit-review/risk-content. Each non-empty, non-comment line is an extended regular expression; matches promote files into high-risk ordering but do not change coverage requirements.

Project-specific semantic context hints can live in .pre-commit-review/context-queries. Each non-empty, non-comment line is an extended regular expression executed only through bounded read-only git grep; these matches can guide dependency or caller checks but never satisfy review coverage.

Review-planning tables and Dependency Summary use TSV because paths, commands, and dependency details may contain commas.

Reducer and subagent automation should prefer Review Plan JSON, Reducer State Snapshot Template, and JSONL sections when present; TSV tables are primarily for human scanning.

tests/

Deterministic shell tests with no model dependency. skill_contract_test.sh pins the cross-document contract between SKILL.md and references/ (forbidden placeholders, required labels, the untranslatable VERDICT field). collect_diff_context_test.sh and full_review_workflow_test.sh exercise the helper script against temporary real Git repositories. parity_golden_test.sh reuses shared parity fixtures plus a dedicated normalizer to keep legacy-vs-Rust comparisons stable. install_smoke_test.sh and install_agent_matrix_test.sh verify the installer across copy/link/dry-run modes and the supported agent matrix. All of them run with plain bash and jq, never call a model, and are safe in CI.

evals/

The LLM-backed evaluation harness is now layered by responsibility:

• trigger-eval.json covers skill triggering behavior
• output-eval.json remains the compatibility umbrella for core output scenarios
• evals/output/routine-output-eval.json, advanced-output-eval.json, visual-output-eval.json, and localization-output-eval.json split output grading into routine, complex, visual, and localization-specific matrices
• evals/taxonomy/marker-eval.json isolates finding-marker and tally expectations for 🔒, ❌, ⚠️, 🧪, 👁️, 📈, and 🧭

Execution entrypoints are layered too:

• output_eval_runner.sh prepares real local fixtures for any one eval file, can optionally invoke an external model runner, and grades saved responses against expected verdicts and required phrases
• --eval-file lets output_eval_runner.sh target one layered output eval JSON such as evals/output/visual-output-eval.json.
• run_layered_output_evals.sh runs the layered output eval matrix end-to-end across the routine, advanced, visual, and localization eval files
• run_marker_eval_checks.sh validates marker-taxonomy coverage and summarizes blocking vs non-blocking case counts
• output_eval_codex_case.sh and output_eval_claude_case.sh run a single eval case per host
• output_eval_codex_runner.sh and output_eval_claude_runner.sh are host-specific thin wrappers that link this checkout into the fixture's project-local skill directory (.agents/skills for Codex, .claude/skills for Claude Code) and delegate to output_eval_runner.sh with host-appropriate non-interactive commands
• output_eval_runner_test.sh is the deterministic self-test for fixture preparation and grading logic
• output_eval_host_wrappers_test.sh verifies the wrappers with mock Codex and Claude binaries so host command templates regress without spending model calls
• run_helper_gateway_probe.sh runs a real-host stage that instruments the bundled helper and selected direct Git commands, then fails if a host inspects Git diff source before attempting scripts/collect_diff_context.sh
• readme_surface_test.sh keeps the README-facing public surface aligned with the documented contract gates and entrypoint inventory
• readme_host_entrypoints_test.sh pins the tiered Host Entrypoints section so the README keeps exposing the host-lane surface by Primary, Analysis, Stage, and Internal / Repo-wide
• eval_contract_test.sh is the repo-wide gate for trigger evals, layered output evals, marker taxonomy assets, and host-lane contract surfaces

Host Entrypoints

For the host-lane workflow, use these scripts by tier:

• Primary: evals/run_host_readiness_pipeline.sh, evals/run_cross_host_readiness.sh
• Default entrypoints for end-to-end single-host or cross-host verification
• Primary / Real Host Smoke: evals/run_real_host_smoke.sh, .github/workflows/real-host-smoke.yml
• Use these when you want one stable entrypoint for real authenticated host smoke runs and artifact collection
• Primary / Output Matrix: evals/run_layered_output_evals.sh, evals/run_marker_eval_checks.sh
• Use these to run the layered output-eval surface and marker-taxonomy checks without hand-selecting individual eval assets
• Analysis: evals/analyze_host_readiness_diff.sh
• Use this to compare cross-host readiness outputs without rerunning each stage
• Stage: evals/check_host_availability.sh, evals/run_helper_gateway_probe.sh, evals/run_layered_host_evals.sh, evals/host_contract_subset.sh
• Use these when debugging or running one host-lane boundary directly
• Internal / Repo-wide: evals/eval_contract_test.sh, host *_test.sh, evals/host_failure_taxonomy.sh
• Important support surfaces, but not normal user-facing entrypoints
• Stage reports: check_host_availability.sh, run_helper_gateway_probe.sh, run_layered_host_evals.sh, and host_contract_subset.sh can emit host-stage-report/v1
• Pipeline report: run_host_readiness_pipeline.sh emits host-readiness-report/v1
• Cross-host and diff reports: run_cross_host_readiness.sh emits cross-host-readiness-report/v1, and analyze_host_readiness_diff.sh emits host-readiness-diff-report/v1

agents/openai.yaml

Provides lightweight agent metadata for environments that expose skills through an agent registry.

install.sh

Installs this skill package into host-specific skills directories for supported AI coding agents.

Quick Install

From a clone of this repository, install globally for any supported agent:

./install.sh --agent codex
./install.sh --agent claude-code
./install.sh --agent gemini-cli
./install.sh --agent kiro-cli

List every supported agent id and its project/global paths:

./install.sh --list-agents

Defaults:

• Global installs use the agent-specific global path shown by --list-agents
• Project installs use the agent-specific project path shown by --list-agents
• --dir PATH overrides both defaults
• AGENT_SKILLS_DIR overrides the global default for all agents
• Dedicated overrides are also supported for existing integrations: CODEX_SKILLS_DIR, CLAUDE_SKILLS_DIR, GEMINI_SKILLS_DIR, KIRO_SKILLS_DIR, and CODEX_HOME
• Backward-compatible aliases are supported: claude, gemini, and kiro

Useful flags:

• --copy copies the skill into the target directory and is the default mode
• --link creates a symlink to this repository, which is useful for local development
• --project installs into the agent's project-local skills directory
• --dir PATH overrides the target skills directory
• --force replaces an existing non-managed target
• --dry-run prints what would happen without changing anything

Examples:

./install.sh --agent cursor --project
./install.sh --agent windsurf --link --project
./install.sh --agent github-copilot --dry-run
./install.sh kiro --dir .kiro/skills

How It Works

The skill resolves review input in this order:

1. A diff explicitly provided by the user
2. Staged changes in the current repository
3. Unstaged changes if nothing is staged
4. Current branch compared with a detected base branch
5. User-provided code without before/after diff
6. If no diff or code is available, the skill asks for staged changes or a provided diff

If the user provides code without a before/after diff, the skill:

• perform a static pre-commit-style review
• labels the review source as user-provided code
• treats the review as partial
• avoids inferring prior behavior unless the user explicitly showed it

When local repository access is available and the user has not explicitly provided review material, the workflow first attempts the helper at scripts/collect_diff_context.sh. Resolve that path relative to the installed pre-commit-review skill package containing SKILL.md, not relative to the user's project root.

The helper is the source of truth for:

• diff source
• review boundaries
• changed file counts
• staged vs. unstaged notes
• untracked file warnings

Only fall back to direct Git inspection when the helper is unavailable at that resolved path, exits non-zero, cannot be executed in the current host, or the user already provided the review material explicitly.

Other Integration Modes

Use as a standalone repository

Clone or copy this repository into the place where your agent runtime expects custom skills.

Example layout:

your-skills/
└── pre-commit-review/
    ├── SKILL.md
    ├── agents/
    ├── references/
    └── scripts/

Then register or expose the skill according to your agent platform's skill-loading mechanism.

Merge into an existing skills collection

If you already maintain a larger skills repository, copy this directory in as one skill package and preserve the relative paths:

• SKILL.md
• scripts/collect_diff_context.sh
• references/
• agents/openai.yaml

The helper script is referenced by the skill instructions, so the directory structure should remain intact unless you also update those references.

Review Output

The expected output is an action-first, fast-scanning pre-commit review with:

• a verdict plus a one-line conclusion
• diff source
• review scope
• change scale
• priority findings with concrete fixes
• the minimum risk and test guidance needed to make a commit decision

The default review should answer three questions first:

• can this be committed now
• what must be fixed before commit
• what should be tested next

Only include deeper intent analysis, before/after logic detail, or extra supporting notes when they materially improve the review.

Final verdicts mean:

• SAFE_TO_COMMIT: reviewed scope looks safe to commit now
• SAFE_TO_COMMIT_WITH_NOTES: safe to commit now, but follow-up notes or review limits exist
• DO_NOT_COMMIT: blocking issue found; do not commit as-is

Safety Characteristics

This package is intentionally conservative:

• it avoids pretending to see local changes when no repository is available
• it distinguishes staged and unstaged review scope, and flags when unstaged changes touch files also staged
• it warns about untracked files not present in git diff
• it never reproduces secret values; flagged credentials are shown as a redacted preview with a rotate suggestion
• it treats large or truncated diffs as a reason to split work and retrieve smaller context, not as permission to skip material units
• it reserves partial triage for advisory fallback and blocks commit-readiness when high-risk units are unreviewed
• it supports coverage-led commit-readiness by requiring every manifest unit to be accounted for before claiming full scope
• it keeps long-review reducer state compact and explicit instead of relying on implicit conversation memory
• it treats semantic context queries as bounded read-only hints, not arbitrary shell commands or coverage substitutes

Limitations

• This repository does not include the runtime that loads or executes the skill.
• The included installer covers common Codex, Claude Code, and Gemini CLI locations, but some local setups may still require --dir overrides.
• The helper script expects a working git executable in the environment.
• On Windows, the helper script and installer require a Unix-compatible environment (such as Git Bash, MSYS2, or WSL) to run correctly.
• The current repository itself may be used outside Git, but local diff collection only works inside a Git repository.

Contributing

Contributions are best focused on:

• improving review heuristics
• tightening safety boundaries
• refining the output template
• making diff collection more robust across repository states

If you change script paths or repository layout, update SKILL.md accordingly. If you update user-facing documentation, keep localized README files synchronized.

Development

Shell scripts (scripts/*.sh, install.sh, tests/*.sh, evals/*.sh) are linted by shellcheck in CI (.github/workflows/lint.yml). Install it locally (brew install shellcheck on macOS) and run shellcheck -s bash scripts/*.sh install.sh tests/*.sh evals/*.sh before submitting changes.

To build the Rust CLI binary locally, run cargo build --release --manifest-path collect-diff-context-cli/Cargo.toml or execute scripts/build_all_binaries.sh.

The deterministic unit test suite is bash tests/*_test.sh. The eval harness also ships deterministic self-tests that do not call a model: bash evals/eval_contract_test.sh, bash evals/output_eval_runner_test.sh, and bash evals/output_eval_host_wrappers_test.sh (or run all eval self-tests via for f in evals/*_test.sh; do bash "$f"; done). The model-backed runners (evals/output_eval_codex_runner.sh, evals/output_eval_claude_runner.sh) require a real Codex or Claude CLI and are not part of CI.

The manual real-host smoke workflow is .github/workflows/real-host-smoke.yml. It is intended for a self-hosted runner that already has authenticated claude and codex CLIs available, and it delegates to evals/run_real_host_smoke.sh.

License

This project is licensed under the Apache License 2.0. See LICENSE.