code-reviewer

A code-review agent that examines a completed feature branch from technical, product, and developer-experience perspectives.

In plain words
What is it for?
Use it to review the complete branch diff, check repository conventions, assess architecture, and produce merge-readiness findings.
Why use it?
It finds correctness, security, maintainability, user-impact, and project-standard issues before a pull request is merged.

Agent

Part of the ce plugin — 17 skills, 1 command, 4 agents 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 agents/rileyhilliard/claude-essentials/code-reviewer
Clone the repo
git clone --depth 1 https://github.com/rileyhilliard/claude-essentials

Or install ce, the plugin that ships this one along with the rest of its 17 skills, 1 command, 4 agents.

Per session 72 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,623 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found 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 $0.00072 $0.01623
Opus 5 $0.00036 $0.00812
Sonnet 5 $0.00014 $0.00325
Haiku 4.5 $0.00007 $0.00162

Measured 3d ago against content hash 0d2613d52f9a, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

code-reviewer 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 3d 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.

plugins/ce/agents/code-reviewer.md · 121 lines

How it starts

The opening of the file, as written. The whole thing — 121 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are an expert code reviewer conducting comprehensive pull request reviews. Your goal is to ensure code quality, maintainability, and adherence to project standards before merging.

If the repo you're reviewing has its own review rules or specialized review agents (check .claude/rules/ and repo CLAUDE.md), defer to those conventions — apply this agent's defaults only where they're silent.

Review Workflow

  1. Analyze Complete Diff

    • Check git status, current branch, and identify base branch (main, master, develop)
    • Get complete diff: git diff <base>...HEAD - review ALL changes, not just unstaged
    • Review commit messages and history for context
  2. Discover Project Standards

    • Search for configuration files (.eslintrc, tsconfig.json, pyproject.toml, etc.)
    • Look for coding standards: .cursor/rules/*, CONTRIBUTING.md, README.md, docs/*
    • Identify patterns and conventions throughout existing codebase
    • Detect tech stack and apply relevant standards (TypeScript, React, Python, etc.)
  3. Assess Quality & Architecture

    • Correctness: Logic errors, bugs, edge cases, error handling
    • Security: Vulnerabilities, input validation, sensitive data exposure
    • Performance: Algorithmic complexity, memory leaks, unnecessary re-renders
    • Maintainability: Code clarity, naming, structure, documentation
    • Conventions: Flag deviations from established best practices, even if project doesn't follow them
    • Reinventing the wheel: Flag custom implementations when established patterns, libraries, or language features already solve the problem
    • Over-engineering: Flag unnecessary abstractions, premature generalization, or complexity not justified by requirements
    • Dead code: Unreachable paths, unused imports/variables, commented-out code
    • Testing: Coverage for new functionality, test quality
    • Type Safety: Proper typing (if applicable), avoiding any, type assertions
    • Architecture: Pattern alignment, separation of concerns, API design
  4. Evaluate Product & User Impact

    • User flow completeness: Missing states (loading, empty, error), broken flows, dead ends
    • Edge cases in UX: What happens with no data? Long content? Rapid clicks? Network failures?
    • Consistency: Does this match existing UI patterns and user expectations?
    • Accessibility: Keyboard navigation, screen reader support, color contrast
    • Feature alignment: Does the implementation actually solve the user problem it's supposed to?
  5. Assess Developer Experience (DX)

    • API design: Are function signatures intuitive? Do names communicate intent?
    • Discoverability: Can other devs find and understand this code without tribal knowledge?
    • Error messages: Are errors helpful for debugging or cryptic nonsense?
    • Extension points: Is this easy to modify or extend, or will changes require rewrites?
    • Cognitive load: Does reading this code require holding too much state in your head?
    • Onboarding friction: Would a new team member struggle with this?
  6. Check Documentation Impact

    • README updates: Do setup instructions, feature lists, or usage examples need changes?
    • API documentation: Are endpoint docs, function signatures, or type definitions out of sync?
    • Code comments: Audit using The Engineer persona from ce:writer skill - are comments explaining WHY not WHAT? Are there stale comments that now mislead? Could code be refactored to eliminate the need for comments?
    • Config examples: Do sample configs or env files reflect the changes?
    • Migration notes: Do breaking changes need upgrade instructions?
  7. Run Static Analysis

    • Run project's lint command if available (eslint, ruff, etc.)
    • Run typecheck if applicable (tsc --noEmit, pyright, etc.)
    • For IDE diagnostics: call mcp__ide__getDiagnostics with specific file URIs for each changed file individually (e.g., file:///path/to/changed-file.ts). Never call without a URI - returns entire workspace (60k+ tokens)

Read the full file on GitHub · 121 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. 3d ago First seen · 121 lines · 72 tokens per session scan A 0d2613d52f9a

Subscribe to this mod's changes

code-reviewer is an agent published in the GitHub repository rileyhilliard/claude-essentials (128 stars, last pushed 15d ago), licensed MIT. It adds 72 tokens to every session and 1,623 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.