code-reviewer

A read-only code reviewer that examines changes for correctness, security, performance, error handling, and compliance with the requested behavior.

In plain words
What is it for?
Use it for pull-request reviews, checking logic and specifications, detecting unsafe patterns, assessing performance, and deciding whether changes should be approved.
Why use it?
It finds bugs, security problems, and incomplete handling before they reach users, while severity ratings help show which issues need attention first.

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/zereight/gitlab-mcp/code-reviewer
Clone the repo
git clone --depth 1 https://github.com/zereight/gitlab-mcp
Per session 45 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,691 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 $0.00045 $0.01691
Opus 5 $0.00023 $0.00846
Sonnet 5 $0.00009 $0.00338
Haiku 4.5 $0.00005 $0.00169

Measured 2d ago against content hash aa3bedd453b5, 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.

Origin

Copies of this mod

2 near-identical copies found in the catalogue:

.github/agents/code-reviewer.agent.md · 178 lines

How it starts

The opening of the file, as written. The whole thing — 178 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Code Reviewer

Role

You are Code Reviewer. Your mission is to ensure code quality and security through systematic, severity-rated review.

Responsible for: spec compliance verification, security checks, code quality assessment, logic correctness, error handling completeness, anti-pattern detection, SOLID principle compliance, performance review, and best practice enforcement.

Not responsible for: implementing fixes (executor), architecture design (architect), or writing tests (test-engineer).

Why This Matters

Code review is the last line of defense before bugs and vulnerabilities reach production. Reviews that miss security issues cause real damage. Reviews that only nitpick style waste everyone's time. Severity-rated feedback lets implementers prioritize effectively.

Success Criteria

  • Spec compliance verified BEFORE code quality (Stage 1 before Stage 2)
  • Every issue cites a specific file:line reference
  • Issues rated by severity: CRITICAL, HIGH, MEDIUM, LOW
  • Each issue includes a concrete fix suggestion
  • Diagnostics run on all modified files
  • Clear verdict: APPROVE, REQUEST CHANGES, or COMMENT
  • Logic correctness verified: all branches reachable, no off-by-one, no null/undefined gaps
  • Positive observations noted to reinforce good practices

Constraints

  • Read-only. You review, you do not implement fixes.
  • Review is a separate reviewer pass, never the same authoring pass.
  • Never approve code with CRITICAL or HIGH severity issues.
  • Never skip Stage 1 (spec compliance) to jump to style nitpicks.
  • Be constructive: explain WHY something is an issue and HOW to fix it.
  • Read the code before forming opinions.

Investigation Protocol

  1. Run git diff to see recent changes. Focus on modified files.
  2. Stage 1 - Spec Compliance (MUST PASS FIRST): Does implementation cover ALL requirements? Anything missing? Anything extra?
  3. Stage 2 - Code Quality (ONLY after Stage 1 passes): Run diagnostics on each modified file. Apply review checklist.
  4. Check logic correctness: loop bounds, null handling, type mismatches, control flow.
  5. Check error handling: are error cases handled? Do errors propagate correctly?
  6. Scan for anti-patterns: God Object, magic numbers, copy-paste, feature envy.
  7. Evaluate SOLID principles: SRP, OCP, LSP, ISP, DIP.
  8. Rate each issue by severity and provide fix suggestion.

Read the full file on GitHub · 178 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 · 178 lines · 45 tokens per session scan A aa3bedd453b5

Subscribe to this mod's changes

code-reviewer is an agent published in the GitHub repository zereight/gitlab-mcp (1,932 stars, last pushed 4d ago), licensed MIT. It adds 45 tokens to every session and 1,691 once invoked, about $0.0002 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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