fallow-review

fallow-review is a skill for Claude Code, Codex from fallow-rs/fallow-skills. It costs 151 tokens per session (4,803 once invoked), scanned A, original, MIT.

A code-review process that uses the relationships between parts of a codebase to identify which changed areas deserve human attention.

In plain words
What is it for?
Use it to review a changeset, rank files by likely risk, identify affected callers, and frame important design questions for the reviewer.
Why use it?
It filters out issues that automated checks can identify and focuses the review on structural decisions and changes with a wider potential impact.

Skill for Claude CodeCodex

Written for Claude Code and Codex: ${CLAUDE_PLUGIN_ROOT} variable, but also agents/openai.yaml present. Also seen: reads .claude/ paths; mentions Claude Code; mentions Codex.

Runs only inside its plugin — its command needs a path that Claude Code sets for a plugin’s own hooks and for nothing else. Install the plugin, not this.

Part of the fallow plugin — 2 skills, 1 command shipped together

Good fit Use it to review a changeset, rank files by likely risk, identify affected callers, and frame important design questions for the reviewer.

Compare 6 skills from other repositories ↓
Install

Getting it into your agent

This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.

Claude Code
/plugin marketplace add fallow-rs/fallow-skills
Claude Code
/plugin install fallow

Made for: Claude Code, Codex.

Or install fallow, the plugin that ships this one along with the rest of its 2 skills, 1 command.

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 fallow-review

README.md
[![agentmods](https://agentmods.dev/badge/skills/fallow-rs/fallow-skills/fallow-review/github.svg)](https://agentmods.dev/skills/fallow-rs/fallow-skills/fallow-review)
Your own site
<a href="https://agentmods.dev/skills/fallow-rs/fallow-skills/fallow-review"><img src="https://agentmods.dev/badge/skills/fallow-rs/fallow-skills/fallow-review/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for fallow-review

Your own site · 80×15
<a href="https://agentmods.dev/skills/fallow-rs/fallow-skills/fallow-review"><img src="https://agentmods.dev/badge/skills/fallow-rs/fallow-skills/fallow-review.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 151 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,803 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • Socket warn 6 Sept 2026
  • Snyk warn 6 Sept 2026
How audits are shown
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 5.1 $0.00151 $0.04803
Opus 5 $0.00076 $0.02402
Sonnet 5 $0.00030 $0.00961
Haiku 4.5 $0.00015 $0.00480

Measured 6d ago against content hash fde7c5fee2bb, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

fallow-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 6d ago.

The scan reads SKILL.md. This mod also ships 2 executable files (hooks/fallow-review-on-feedback.sh, hooks/fallow-review-session-init.sh), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

fallow/skills/fallow-review/SKILL.md · 235 lines

How it starts

The opening of the file, as written. The whole thing — 235 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Fallow Review: graph-grounded code review

fallow review turns a changeset into a deterministic, graph-derived review brief and an agent-contract loop. It answers "where do I look, and what calls actually need human taste?" rather than "will CI block this?" (that is fallow audit, which gates). review always exits 0, so it is safe to run regardless of verdict.

The four jobs it does, in order:

  • subtract: dead code, complexity, duplication, and styling for the changed files are reported and kept OUT of the judgment loop, so attention is not spent on what a deterministic check already owns.
  • focus: changed-file units are ranked by a composite attention score (fan-in/out, risk zone, change shape) with a review-here / not-prioritized label and a full deprioritized escape-hatch list, so nothing is hidden.
  • structure: the decision surface lifts the handful of consequential STRUCTURAL decisions out of the diff and frames each as a judgment question, capped to a working-memory-sized set, each anchored to a signal_id fallow emitted.
  • direct: the walkthrough guide hands an agent a graph-derived digest, the review direction, a graph-snapshot pin, and the exact judgment schema to return.

When to use

  • Reviewing a PR, branch, or diff (AI-generated or human-written) before merge.
  • After an agent has done work and removed the fallow findings it could; this surfaces what is left for human/agent taste.
  • Producing inline-reviewable judgments that can flow back to the agent that wrote the code.

When NOT to use

  • Gating CI on a pass/fail verdict: use fallow audit (it exits non-zero on a fail verdict).
  • Whole-project health, cleanup, or dead-code reports: use the fallow skill.

Quick human brief

# Auto-detect the base (merge-base against the upstream / remote default):
fallow review

# Pin the base, or scope to a precise diff:
fallow review --base origin/main
git diff --find-renames origin/main...HEAD | fallow review --base origin/main --diff-stdin

Read the full file on GitHub · 235 lines

Files

What ships with it

5 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 6d ago Changed · -6 lines fde7c5fee2bb
  2. 12d ago First seen · 241 lines · 151 tokens per session scan A f4ca5b4e8fd6

Subscribe to this mod's changes

fallow-review is a skill published in the GitHub repository fallow-rs/fallow-skills (121 stars, last pushed yesterday), licensed MIT. It adds 151 tokens to every session and 4,803 once invoked, about $0.0008 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.