plan-review

plan-review is a skill for Claude Code from Mathews-Tom/armory. It costs 59 tokens per session (1,631 once invoked), scanned A, original, MIT.

A read-only check of a technical plan before implementation begins.

In plain words
What is it for?
Use it to review product, engineering, or combined plans and receive a severity-tagged verdict to ship, rethink, or reject them.
Why use it?
It exposes unclear scope, risky assumptions, missing work, and possible failure modes while changes are still inexpensive.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: names the AskUserQuestion tool.

Part of the armory plugin — 85 skills, 1 agent shipped together

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/mathews-tom/armory/plan-review
Any agent
npx skills add Mathews-Tom/armory --skill plan-review
Clone the repo
git clone --depth 1 https://github.com/Mathews-Tom/armory

Made for: Claude Code.

Or install armory, the plugin that ships this one along with the rest of its 85 skills, 1 agent.

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 plan-review

README.md
[![agentmods](https://agentmods.dev/badge/skills/mathews-tom/armory/plan-review.svg)](https://agentmods.dev/skills/mathews-tom/armory/plan-review)
Your own site
<a href="https://agentmods.dev/skills/mathews-tom/armory/plan-review"><img src="https://agentmods.dev/badge/skills/mathews-tom/armory/plan-review.svg" alt="Measured on agentmods" height="20"></a>
Per session 59 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,631 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 5.1 $0.00059 $0.01631
Opus 5 $0.00030 $0.00816
Sonnet 5 $0.00012 $0.00326
Haiku 4.5 $0.00006 $0.00163

Measured 6d ago against content hash 5a2c3f143a8b, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

plan-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.

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.

skills/plan-review/SKILL.md · 199 lines

How it starts

The opening of the file, as written. The whole thing — 199 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Plan Review Skill

Purpose

Execute a structured pre-implementation audit of a technical plan, proposal, or design document. The goal is to surface risks, bad assumptions, missing pieces, and scope problems before any code is written — when course corrections are cheapest.

This skill is read-only. It never modifies code. It produces a severity-tagged review document with a final ship/rethink/reject verdict.

Step 0 — Mode Selection

Ask the user a single question via AskUserQuestion:

Which review lens? (1) Product — scope, user impact, business alignment. (2) Engineering — architecture, failure modes, test strategy, performance. (3) Combined (default) — both lenses integrated.

Accept the answer and proceed. Do not ask follow-up configuration questions.

Also assess scope size from the plan:

  • Small change (single file, ~100 lines or fewer): deliver a compressed 4-section review — Scope, Risks, Missing, Verdict. Skip the full multi-section template.
  • Standard change: execute the full review sequence below.

Full Review Sequence

1. Plan Comprehension

Read the plan end-to-end. Produce a 2–3 sentence summary confirming understanding. Explicitly list:

  • Stated goals — what the plan claims to achieve.
  • Non-goals — what is explicitly out of scope.
  • Constraints — budget, timeline, compatibility, team size, or technology constraints mentioned or implied.

If the summary is wrong, the user corrects it here before the rest of the review proceeds on a false foundation.

2. Assumption Challenge

Extract every implicit assumption. For each one:

Assumption If wrong? Supporting evidence What falsifies it?

Common assumption categories to probe:

  • Data availability and shape
  • Third-party API stability and rate limits
  • Team familiarity with chosen tools
  • Performance characteristics of dependencies
  • Backward compatibility requirements
  • Deployment environment capabilities

Read the full file on GitHub · 199 lines

Files

What ships with it

2 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 First seen · 199 lines · 59 tokens per session scan A 5a2c3f143a8b

Subscribe to this mod's changes

plan-review is a skill published in the GitHub repository Mathews-Tom/armory (316 stars, last pushed yesterday), licensed MIT. It adds 59 tokens to every session and 1,631 once invoked, about $0.0003 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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