Agent Native

code-review

Reviews code changes against two independent axes: whether the code follows the repository's documented coding standards, and whether it implements the…

by mattpocockCommunityNot reviewed

Community author

Agents
Claude Code, Codex, Cursor, Gemini CLI, GitHub Copilot, OpenCode, claude.ai and API
License
MIT (permissive)
Pin
b0618bcpinned Oct 9, 2026
Context cost
about 1,500 tokenswhen the skill loads
GitHub stars
280,909on mattpocock/skills
Scripts
None found

What it does

“Review the changes since a fixed point (commit, branch, tag, or merge-base) along two axes: Standards (does the code follow this repo's documented coding standards?) and Spec (does the code match what the originating issue/spec asked for?). Runs both reviews in parallel sub-agents and reports them side by side. Use when the user wants to review a branch, a PR, work-in-progress changes, or asks to "review since X".”
The author's description, from SKILL.md

Generated summary from the skill's own text

Reviews code changes against two independent axes: whether the code follows the repository's documented coding standards, and whether it implements the specification from the originating issue or spec file. The skill runs both reviews as parallel sub-agents to keep their evaluations separate, then aggregates their findings side by side.

When to use it

  • User asks to review a branch, pull request, or work-in-progress changes
  • Reviewing code against documented standards and feature specifications
  • User says "review since" a specific commit, branch, tag, or merge point
  • Assessing whether changes match both coding conventions and requirements

When not to

  • No documented standards or spec exists and user has no reference point
  • Reviewing only code style where automated linting tools already enforce rules
  • Quick informal feedback is needed rather than structured two-axis analysis

Install

These commands install from the publisher's repository and need no account.

skills CLI

npx skills add mattpocock/skills --skill code-review

Installs from the repository's default branch, which may have changed since the commit we checked.

GitHub CLI 2.90 or later

gh skill install mattpocock/skills code-review@b0618bc436ad893b3c5e84e55fba86586d34a404

Installs the commit we checked (b0618bc).

Copy by hand

Download the folder at b0618bc and put it in .claude/skills/code-review for Claude Code and in .agents/skills/code-review for Codex, Cursor, Gemini CLI, GitHub Copilot and OpenCode.

Skill folder on GitHub at b0618bc

Copy for your agent

A prompt for any coding agent. It installs this skill from GitHub at the pinned commit, copies the files as they are, and runs nothing unless you ask.

Prompt

Install the agent skill "code-review" by mattpocock.

Source, pinned to commit b0618bc436ad893b3c5e84e55fba86586d34a404:
https://github.com/mattpocock/skills/tree/b0618bc436ad893b3c5e84e55fba86586d34a404/skills/engineering/code-review

1. Download that folder at exactly this commit. Do not use the default branch.
2. Copy every file unchanged, keeping the folder structure, into .claude/skills/code-review/ for Claude Code and .agents/skills/code-review/ for Codex, Cursor, Gemini CLI, GitHub Copilot and OpenCode. Create the folders if they do not exist.
3. Do not edit the files, and do not run any script in the folder unless I ask you to.
4. When you are done, list the files you copied and where you put them.

Listing and checks: https://www.agentnative.dev/skills/mattpocock/code-review

SKILL.md at the pin

---
name: code-review
description: "Review the changes since a fixed point (commit, branch, tag, or merge-base) along two axes: Standards (does the code follow this repo's documented coding standards?) and Spec (does the code match what the originating issue/spec asked for?). Runs both reviews in parallel sub-agents and reports them side by side. Use when the user wants to review a branch, a PR, work-in-progress changes, or asks to \"review since X\"."
---

Two-axis review of the diff between `HEAD` and a fixed point the user supplies:

- **Standards**: does the code conform to this repo's documented coding standards?
- **Spec**: does the code faithfully implement the originating issue / spec?

Both axes run as **parallel sub-agents** so they don't pollute each other's context, then this skill aggregates their findings.

The issue tracker should have been provided to you. If not, tell the user to run `/setup-matt-pocock-skills`.

## Process

### 1. Pin the fixed point

Whatever the user said is the fixed point (a commit SHA, branch name, tag, `main`, `HEAD~5`, etc.). If they didn't specify one, ask for it.

Capture the diff command once: `git diff <fixed-point>...HEAD` (three-dot, so the comparison is against the merge-base). Also note the list of commits via `git log <fixed-point>..HEAD --oneline`.

Before going further, confirm the fixed point resolves (`git rev-parse <fixed-point>`) and the diff is non-empty. A bad ref or empty diff should fail here, not inside two parallel sub-agents.

### 2. Identify the spec source

Look for the originating spec, in this order:

1. Issue references in the commit messages (`#123`, `Closes #45`, GitLab `!67`, etc.), fetched via the workflow in the tracker doc.
2. A path the user passed as an argument.
3. A spec file under `docs/`, `specs/`, or `.scratch/` matching the branch name or feature.
4. If nothing is found, ask the user where the spec is. If they say there isn't one, the **Spec** sub-agent will skip and report "no spec available".

### 3. Identify the standards sources

Search the repo for every file that documents how code should be written. When `CODING_STANDARDS.md` or `CONTRIBUTING.md` exists, it must be on the list.

On top of whatever the repo documents, the Standards axis always carries the **smell baseline** below: a fixed set of Fowler code smells (_Refactoring_, ch.3) that applies even when a repo documents nothing. Two rules bind it:

- **The repo overrides.** A documented repo standard always wins; where it endorses something the baseline would flag, suppress the smell.
- **Always a judgement call.** Each smell is a labelled heuristic ("possible Feature Envy"), never a hard violation. Like any standard here, skip anything tooling already enforces.

Each smell reads *what it is* → *how to fix*; match it against the diff:

- **Mysterious Name**: a function, variable, or type whose name doesn't reveal what it does or holds. → rename it; if no honest name comes, the design's murky.
- **Duplicated Code**: the same logic shape appears in more than one hunk or file in the change. → extract the shared shape, call it from both.
- **Feature Envy**: a method that reaches into another object's data more than its own. → move the method onto the data it envies.
- **Data Clumps**: the same few fields or params keep travelling together (a type wanting to be born). → bundle them into one type, pass that.
- **Primitive Obsession**: a primitive or string standing in for a domain concept that deserves its own type. → give the concept its own small type.
- **Repeated Switches**: the same `switch`/`if`-cascade on the same type recurs across the change. → replace with polymorphism, or one map both sites share.
- **Shotgun Surgery**: one logical change forces scattered edits across many files in the diff. → gather what changes together into one module.
- **Divergent Change**: one file or module is edited for several unrelated reasons. → split so each module changes for one reason.
- **Speculative Generality**: abstraction, parameters, or hooks added for needs the spec doesn't have. → delete it; inline back until a real need shows.
- **Message Chains**: long `a.b().c().d()` navigation the caller shouldn't depend on. → hide the walk behind one method on the first object.
- **Middle Man**: a class or function that mostly just delegates onward. → cut it, call the real target direct.
- **Refused Bequest**: a subclass or implementer that ignores or overrides most of what it inherits. → drop the inheritance, use composition.

### 4. Spawn both sub-agents in parallel

Issue both sub-agent calls together, in the foreground, and aggregate the reports they return.

**Standards sub-agent prompt** should include:

- The full diff command and commit list.
- The list of standards-source files you found in step 3, **plus the smell baseline from step 3** pasted in full (the sub-agent has no other access to it).
- The brief: "Report, per file/hunk where relevant, (a) every place the diff violates a documented standard: cite the standard (file + the rule); and (b) any baseline smell you spot: name it and quote the hunk. Distinguish hard violations from judgement calls: documented-standard breaches can be hard, but baseline smells are always judgement calls, and a documented repo standard overrides the baseline. Skip anything tooling enforces. Under 400 words."

**Spec sub-agent prompt** should include:

- The diff command and commit list.
- The path or fetched contents of the spec.
- The brief: "Report: (a) requirements the spec asked for that are missing or partial; (b) behaviour in the diff that wasn't asked for (scope creep); (c) requirements that look implemented but where the implementation looks wrong. Quote the spec line for each finding. Under 400 words."

If the spec is missing, skip the Spec sub-agent and note this in the final report.

### 5. Aggregate

Present the two reports under `## Standards` and `## Spec` headings, verbatim or lightly cleaned. Do **not** merge or rerank findings, because the two axes are deliberately separate (see _Why two axes_).

End with a one-line summary: total findings per axis, and the worst issue _within each axis_ (if any). Don't pick a single winner across axes: that's the reranking the separation exists to prevent.

## Why two axes

A change can pass one axis and fail the other:

- Code that follows every standard but implements the wrong thing → **Standards pass, Spec fail.**
- Code that does exactly what the issue asked but breaks the project's conventions → **Spec pass, Standards fail.**

Reporting them separately stops one axis from masking the other.

From mattpocock/skills at b0618bc, shown as plain text under its license: MIT (permissive). The license text is in LICENSE.

View SKILL.md on GitHub at b0618bc

Files

2 files, 6.8 KB in total. Each file has a sha256 in the pin's manifest; the first 12 characters are shown.

Skill folder on GitHub at b0618bc
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