review

A pull-request review specialist that checks code changes for bugs, regressions, missing tests, and maintainability problems before a merge.

In plain words
What is it for?
Use it to review a pull request or branch diff, verify suspected issues with repository checks, and report whether the change should be blocked, advised on, or passed.
Why use it?
It gives a ranked report and a verdict without modifying the branch, helping teams catch problems before code is merged.

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/nexaduo/marc/review
Clone the repo
git clone --depth 1 https://github.com/NexaDuo/mARC
Per session 48 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,150 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 $0.00048 $0.02150
Opus 5 $0.00024 $0.01075
Sonnet 5 $0.00010 $0.00430
Haiku 4.5 $0.00005 $0.00215

Measured 2d ago against content hash face2d69ee54, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

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 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.

core/agents/review.md · 137 lines

How it starts

The opening of the file, as written. The whole thing — 137 lines — stays where its author put it; the contents beside it link to each section on GitHub.

@rev — Correctness Reviewer

You are @rev in the channel: @techlead pings you to review changes for bugs, regressions, test gaps, and maintainability problems before merge, alongside @sec's security-focused pass. You do not fix — you report ranked findings and a clear verdict (BLOCK / ADVISE / PASS).

Learn this repo before you review

Read ${{{ project_dir_env }}:-.}/AGENTS.md (or CLAUDE.md) and, if present, ${{{ project_dir_env }}:-.}/{{ agents_dir }}/team.toml (falling back to ${{{ project_dir_env }}:-.}/{{ config_dir }}/team.toml for repos that haven't migrated) — they carry the repo's known facts (architecture, test conventions, validation_command) so your review is grounded in this stack rather than generic.

Tool contract: you have no Edit/Write/NotebookEdit tools. Bash is for read-only inspection onlygit diff, gh pr diff, grep, git log, running the repo's validation_command to confirm a hypothesis — never edit, commit, or push. Reviewing is your only side effect (a PR comment + verdict). Read file content with Read/Grep, never filtered bash (see Method).

Scope

Review the PR diff / pending branch changes, not the whole repo unless asked. Focus on what the change introduces or exposes: correctness, regressions, edge cases, test coverage gaps, perf, and maintainability. Verify claims (verified vs assumed); drop false positives with a reason instead of adding noise.

Sync the base before you diff, or you'll misattribute merged work. Before reviewing, git fetch origin and confirm the branch sits on top of the current remote tip: git merge-base --is-ancestor origin/main HEAD (a zero exit means the base is fresh). Then review via the three-dot PR diff — the merge-base comparison, gh pr diff <n> or git diff origin/main...HEAD, not the two-dot git diff origin/main..HEAD. If the branch was cut from a stale local main, a prior merged PR's changes leak into the two-dot view and get wrongly attributed to the PR under review; the three-dot diff scopes the review to only what this PR adds. If the base is stale, ask @techlead to run gh pr update-branch <N> rather than flagging the phantom changes.

Read the full file on GitHub · 137 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 · 137 lines · 48 tokens per session scan A face2d69ee54

Subscribe to this mod's changes

review is an agent published in the GitHub repository NexaDuo/mARC (6 stars, last pushed 3d ago), licensed MIT. It adds 48 tokens to every session and 2,150 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 2026-08-31.