subagent-review

subagent-review is a skill for Claude Code from NikiforovAll/claude-code-rules. It costs 52 tokens per session (787 once invoked), scanned A, a copy of simplify, Apache-2.0.

A one-time code review process that examines changed files with three separate temporary reviewers focused on reuse, quality, and efficiency. It also directs the process to fix issues that the reviewers find.

In plain words
What is it for?
Reviewing recent code changes, finding existing helpers that should be reused, checking implementation quality, and improving inefficient or unnecessarily complex code.
Why use it?
Using separate reviews helps catch duplicated code, avoidable complexity, and quality problems in a change. It provides a repeatable review for work that does not need permanent reviewers.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter. Also seen: mentions subagents.

Part of the handbook-code-review plugin — 2 skills, 1 agent shipped together

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/nikiforovall/claude-code-rules/subagent-review
Any agent
npx skills add NikiforovAll/claude-code-rules --skill subagent-review
Clone the repo
git clone --depth 1 https://github.com/NikiforovAll/claude-code-rules

Made for: Claude Code.

Or install handbook-code-review, the plugin that ships this one along with the rest of its 2 skills, 1 agent.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for subagent-review

README.md
[![agentmods](https://agentmods.dev/badge/skills/nikiforovall/claude-code-rules/subagent-review.svg)](https://agentmods.dev/skills/nikiforovall/claude-code-rules/subagent-review)
Your own site
<a href="https://agentmods.dev/skills/nikiforovall/claude-code-rules/subagent-review"><img src="https://agentmods.dev/badge/skills/nikiforovall/claude-code-rules/subagent-review.svg" alt="Measured on agentmods" height="20"></a>
Per session 52 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 787 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 88% copy Near-identical to another mod in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00052 $0.00787
Opus 5 $0.00026 $0.00394
Sonnet 5 $0.00010 $0.00157
Haiku 4.5 $0.00005 $0.00079

Measured 6d ago against content hash 8787e2779e42, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

subagent-review scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 6d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

This is a copy

88% identical to simplify — 19 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

plugins/handbook-code-review/skills/subagent-review/SKILL.md · 56 lines

How it starts

The opening of the file, as written. The whole thing — 56 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Subagent Review: One-Shot Code Review

Review all changed files for reuse, quality, and efficiency. Fix any issues found.

Phase 1: Identify Changes

Run git diff (or git diff HEAD if there are staged changes) to see what changed. If there are no git changes, review the most recently modified files that the user mentioned or that you edited earlier in this conversation.

Phase 2: Launch Three Review Agents in Parallel

Use the Agent tool to launch all three agents concurrently in a single message. Pass each agent the full diff so it has the complete context.

Agent 1: Code Reuse Review

For each change:

  1. Search for existing utilities and helpers that could replace newly written code. Look for similar patterns elsewhere in the codebase — common locations are utility directories, shared modules, and files adjacent to the changed ones.
  2. Flag any new function that duplicates existing functionality. Suggest the existing function to use instead.
  3. Flag any inline logic that could use an existing utility — hand-rolled string manipulation, manual path handling, custom environment checks, ad-hoc type guards, and similar patterns are common candidates.

Agent 2: Code Quality Review

Review the same changes for hacky patterns:

  1. Redundant state: state that duplicates existing state, cached values that could be derived, observers/effects that could be direct calls
  2. Parameter sprawl: adding new parameters to a function instead of generalizing or restructuring existing ones
  3. Copy-paste with slight variation: near-duplicate code blocks that should be unified with a shared abstraction
  4. Leaky abstractions: exposing internal details that should be encapsulated, or breaking existing abstraction boundaries
  5. Stringly-typed code: using raw strings where constants, enums (string unions), or branded types already exist in the codebase
  6. Unnecessary nesting: wrapper elements that add no layout value
  7. Unnecessary comments: comments explaining WHAT the code does — delete; keep only non-obvious WHY (hidden constraints, subtle invariants, workarounds)

Read the full file on GitHub · 56 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 6d ago First seen · 56 lines · 52 tokens per session scan A 8787e2779e42

Subscribe to this mod's changes

subagent-review is a skill published in the GitHub repository NikiforovAll/claude-code-rules (141 stars, last pushed 7d ago), licensed Apache-2.0. It adds 52 tokens to every session and 787 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 88% identical to simplify, differing in 19 lines, and is treated as a copy.

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