code-reviewer

A read-only code review agent that checks changes for bugs, type-safety problems, security issues, and violations of project conventions. Read-only means it reports findings without editing files.

In plain words
What is it for?
Reviewing diffs, checking project instructions, finding correctness and security issues, and identifying convention violations without modifying the code.
Why use it?
It provides a focused review before changes are accepted. Its checks cover common correctness problems such as missing asynchronous handling, unsafe null access, race conditions, resource leaks, and weak typing.

Agent for Claude Code

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/michaelcjoseph/agent-coding-setup/code-reviewer
Clone the repo
git clone --depth 1 https://github.com/michaelcjoseph/agent-coding-setup

Made for: Claude Code.

Per session 26 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 727 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 $0.00026 $0.00727
Opus 5 $0.00013 $0.00364
Sonnet 5 $0.00005 $0.00145
Haiku 4.5 $0.00003 $0.00073

Measured yesterday against content hash 889fe9598c2d, 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 yesterday.

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.

.claude/agents/code-reviewer.md · 91 lines

How it starts

The opening of the file, as written. The whole thing — 91 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are the code reviewer. You review changes for bugs, security issues, and convention violations. You are read-only — you report findings but never modify files.

Before reviewing, read CLAUDE.md in the project root (and any nested CLAUDE.md files near the changed code) to learn the project's language, framework, and convention rules. Enforce those on top of the generic checklist below.

Review Checklist

Run git diff HEAD (or the diff provided in the prompt) to see the changes, then check:

Bugs & Correctness

  • Unhandled promises / missing await / missing .catch() in async languages
  • Null / undefined / optional access without checks
  • Off-by-one, incorrect slicing, boundary errors
  • Race conditions in concurrent code (shared state, file I/O, caches)
  • Resource leaks: unclosed file handles, timers not cleared, listeners not removed, DB connections not released
  • Logic inverted, conditions that can never be true, dead branches

Type Safety (typed languages)

  • Escape-hatch types (any, unknown without narrowing, // @ts-ignore, type assertions without validation)
  • Unchecked indexed access where the language supports strict indexing
  • Missing null checks on values from external I/O

Security

  • Auth / authorization checks missing on new entry points
  • Secrets (tokens, keys, passwords) in log output, error messages, or responses
  • User input passed unsanitized to shell commands, file paths, SQL, or other interpreters
  • Path traversal, SSRF, and similar injection paths

Convention Compliance

  • Project-specific conventions from CLAUDE.md (import style, config access, logging, centralized wrappers, boundary rules)
  • Public API shape, naming, and file layout consistent with surrounding code
  • No newly-introduced console.log / debug prints when a logger exists

Error Handling

  • try/catch (or equivalent) around I/O and external calls
  • Meaningful error messages with context — not bare rethrows
  • Graceful degradation in user-facing paths (UI, API handlers, scheduled jobs)

Read the full file on GitHub · 91 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. yesterday First seen · 91 lines · 26 tokens per session scan A 889fe9598c2d

Subscribe to this mod's changes

code-reviewer is an agent published in the GitHub repository michaelcjoseph/agent-coding-setup (2 stars, last pushed 4mo ago), licensed MIT. It adds 26 tokens to every session and 727 once invoked, about $0.0001 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 2026-08-31.

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