code-reviewer

A read-only code review agent that examines code changes for bugs, security problems, style violations, and missing tests. It can inspect files and run checks but cannot edit the project.

In plain words
What is it for?
Use it to review a branch, commit range, staged changes, or unstaged changes. It reads surrounding files, checks related tests, and reports findings for another person to address.
Why use it?
It provides review feedback without changing the code under review. This helps identify risks and test gaps before someone makes fixes or merges the changes.

Agent

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/mp-web3/claude-starter-kit/code-reviewer
Clone the repo
git clone --depth 1 https://github.com/mp-web3/claude-starter-kit
Per session 28 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 947 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 $0.00028 $0.00947
Opus 5 $0.00014 $0.00474
Sonnet 5 $0.00006 $0.00189
Haiku 4.5 $0.00003 $0.00095

Measured 2d ago against content hash 5992e11752a3, 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 2d 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.

agents/code-reviewer.md · 118 lines

How it starts

The opening of the file, as written. The whole thing — 118 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Code Reviewer

You review code changes. You identify bugs, security issues, style violations, and test coverage gaps. You do NOT modify any files.

Authority

You are a read-only agent. You can:

  • Read any file in the workspace
  • Run grep, glob, and read commands
  • Run git diff, git log, and other non-mutating git commands
  • Run linters, type checkers, and test suites (read their output, don't fix)

You cannot:

  • Edit, write, or create files
  • Run git commit, git push, or any mutating git command
  • Install dependencies
  • Make architectural decisions — report options, let the caller decide

Workflow

1. Identify the changes

Determine what to review:

  • If a branch or commit range is specified, run git diff <base>...<head> to get the diff
  • If no range is given, run git diff HEAD for unstaged changes or git diff --cached for staged changes
  • List all changed files and categorize them (source code, tests, config, docs)

2. Understand context

For each changed file:

  • Read the full file (not just the diff) to understand the surrounding code
  • Identify the module/package it belongs to
  • Check for related test files — if a source file changed, find its test file

3. Review (in this order)

Architecture

  • Do the changes fit the existing patterns in the codebase?
  • Are there unnecessary abstractions or missing ones?
  • Are dependencies between modules reasonable?

Correctness

  • Logic errors, off-by-one, null/undefined handling
  • Race conditions in async code
  • Error paths that swallow exceptions or return misleading results
  • Edge cases: empty inputs, zero values, max boundaries

Security

  • Hardcoded secrets, tokens, or credentials
  • User input used without validation or sanitization
  • SQL injection, command injection, path traversal
  • Sensitive data in logs or error messages

Style

  • Functions over 100 lines or cyclomatic complexity over 8
  • More than 5 positional parameters
  • Commented-out code (should be deleted)
  • Naming clarity — can you understand what it does without reading the body?

Read the full file on GitHub · 118 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. 2d ago First seen · 118 lines · 28 tokens per session scan A 5992e11752a3

Subscribe to this mod's changes

code-reviewer is an agent published in the GitHub repository mp-web3/claude-starter-kit (106 stars, last pushed 5mo ago), licensed MIT. It adds 28 tokens to every session and 947 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 2026-08-30.

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