code-review

code-review is a skill for Claude Code, Codex from genai-io/san. It costs 83 tokens per session (1,065 once invoked), scanned A, original, Apache-2.0.

A correctness-focused review of changed code that looks for logic errors, crashes, bad error handling, concurrency problems, resource leaks, and edge cases.

In plain words
What is it for?
Use it to review current changes or recently modified files, report findings by severity, and optionally apply fixes when requested.
Why use it?
It concentrates the review on defects that make software behave incorrectly, rather than on style or general cleanup.

Skill for Claude CodeCodex

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/genai-io/san/code-review
Any agent
npx skills add genai-io/san --skill code-review
Clone the repo
git clone --depth 1 https://github.com/genai-io/san

Made for: Claude Code, Codex.

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 code-review

README.md
[![agentmods](https://agentmods.dev/badge/skills/genai-io/san/code-review.svg)](https://agentmods.dev/skills/genai-io/san/code-review)
Your own site
<a href="https://agentmods.dev/skills/genai-io/san/code-review"><img src="https://agentmods.dev/badge/skills/genai-io/san/code-review.svg" alt="Measured on agentmods" height="20"></a>
Per session 83 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,065 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 $0.00083 $0.01065
Opus 5 $0.00042 $0.00532
Sonnet 5 $0.00017 $0.00213
Haiku 4.5 $0.00008 $0.00106

Measured 3d ago against content hash 7b7e707f26ea, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

code-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 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.

.san/personas/software-engineer/skills/code-review/SKILL.md · 103 lines

How it starts

The opening of the file, as written. The whole thing — 103 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Code Review: Correctness

Review the changed code for correctness bugs — cases where it does the wrong thing, crashes, corrupts state, or breaks a contract. This skill is deliberately scoped to bugs. Do not report reuse, quality, style, or efficiency cleanups here; those belong to a separate cleanup pass (San's simplify skill, where present).

If the arguments include --fix, apply fixes after reporting. Otherwise report only and offer to fix. A leading focus area (e.g. concurrency) narrows the review to that dimension.

Phase 1: Identify Changes

Run git diff (or git diff HEAD when changes are staged) to see what changed. If there are no git changes, review the most recently modified files the user named or that you edited earlier in this conversation. Read enough of the surrounding code that each changed line can be judged in context — a line is rarely a bug on its own, only against the code that calls it and the code it calls.

Phase 2: Launch Review Agents in Parallel

Use the Agent tool to launch the dimension agents concurrently in a single message (foreground — do NOT set run_in_background). Pass each agent the full diff plus the context it needs. Each agent returns a list of findings; every finding must carry:

  • a severitycritical (crash, data loss, security), high (wrong result on a realistic input), medium (wrong only in an edge case), low (fragile, latent);
  • a file:line reference;
  • a concrete failure scenario — specific inputs or interleaving that lead to the wrong outcome. A finding with no scenario is a guess; drop it.

Agent 1: Logic & Control Flow

  • Off-by-one, wrong comparison or boolean operator, inverted condition.
  • Incorrect boundary handling; loops that skip the first/last item or run one too many times.
  • Branches that can't be reached, or that fall through when they shouldn't.
  • Wrong operator precedence; integer division or truncation where not intended.

Agent 2: Nil, Errors & Return Values

Read the full file on GitHub · 103 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 · 103 lines · 83 tokens per session scan A 7b7e707f26ea

Subscribe to this mod's changes

code-review is a skill published in the GitHub repository genai-io/san (75 stars, last pushed 6d ago), licensed Apache-2.0. It adds 83 tokens to every session and 1,065 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.

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