| name | code-review |
| description | Two-axis diff review: Standards (follows coding style?) and Spec (matches issue/PRD?). Runs parallel sub-agents. Use when user wants review of branch, PR, or asks "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?
- Ponytail style: no boilerplate comments, no docblocks for trivial code, code is source of truth
- YAGNI: no speculative code, no abstractions before they're needed
- Shortest correct diff wins, deletion over addition
- Existing OSS preferred over custom build (unless user explicitly says build from scratch)
- Spec — does the code faithfully implement the originating issue / PRD / 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 — run /setup-matt if docs/agents/issue-tracker.md is missing.
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:
- Issue references in the commit messages (
#123, Closes #45, GitLab !67, etc.) — fetch via the workflow in docs/agents/issue-tracker.md.
- A path the user passed as an argument.
- A PRD/spec file under
docs/, specs/, or .scratch/ matching the branch name or feature.
- 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
Anything in the repo that documents how code should be written, such as CODING_STANDARDS.md or CONTRIBUTING.md.
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 — and, 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.
- Dead Code — unused exports, unreachable branches, parameters no caller uses, commented-out code, files nothing imports. → remove it; version control remembers.
- 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
Send a single message with two Agent tool calls. Use the general-purpose subagent for both.
Standards sub-agent prompt — include:
- The full diff command and commit list.
- The list of standards-source files you found in step 3 (including
CODING_STANDARDS.md), 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 — 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 — 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.
