plan-critic

plan-critic is an agent for coding agents from nicknisi/ideation. It costs 54 tokens per session (2,474 once invoked), scanned A, original, MIT.

An adversarial reviewer for checking a proposed software plan before approval. It examines the plan through one assigned lens, such as scope or hidden dependencies.

In plain words
What is it for?
It helps review contract data against the codebase and return structured findings without changing project files.
Why use it?
It helps expose unsupported assumptions, unnecessary work, missing dependencies, or weak success checks before implementation begins.

Agent

Part of the ideation plugin — 7 skills, 3 agents 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 agents/nicknisi/ideation/plan-critic
Clone the repo
git clone --depth 1 https://github.com/nicknisi/ideation

Or install ideation, the plugin that ships this one along with the rest of its 7 skills, 3 agents.

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-critic

README.md
[![agentmods](https://agentmods.dev/badge/agents/nicknisi/ideation/plan-critic.svg)](https://agentmods.dev/agents/nicknisi/ideation/plan-critic)
Your own site
<a href="https://agentmods.dev/agents/nicknisi/ideation/plan-critic"><img src="https://agentmods.dev/badge/agents/nicknisi/ideation/plan-critic.svg" alt="Measured on agentmods" height="20"></a>
Per session 54 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,474 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. 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 $0.00054 $0.02474
Opus 5 $0.00027 $0.01237
Sonnet 5 $0.00011 $0.00495
Haiku 4.5 $0.00005 $0.00247

Measured 3d ago against content hash af1c60db4187, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

plan-critic scanned grade A with 1 finding 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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

- **Prose in the `cmd` slot** — a `cmd` must be runnable shell, not a description ("start the server & then curl it" is prose; contract-gen rejects it at render time, so catch it here where it's a one-line fix).
agents/plan-critic.md · 143 lines

How it starts

The opening of the file, as written. The whole thing — 143 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Plan Critic — Adversarial Pre-Approval Review

Try to break the plan before the user sees it. Read the contract data, verify its claims against the codebase, and return findings through a single assigned lens. You critique the plan, not the prose, and you never edit files.

Input

You receive:

  • Contract data path — path to contract-data.json (the pre-render plan: goals, success criteria, scope tiers, execution phases)
  • Project directory — where ideation artifacts live (e.g., docs/ideation/{slug}/)
  • Lens — exactly one of scope-creep, over-engineering, hidden-dependency, success-criteria. Critique only through this lens; ignore concerns that belong to the other three.

Workflow

1. Read the Contract Data

Read contract-data.json. Extract the parts your lens cares about:

  • goals, successCriteria — what the plan promises and how it claims to verify success
  • scope.mvp, scope.full, scope.stretch, scope.outOfScope — what's in and out, and at which tier
  • execution.phases — sequencing, prereqs, risk, and which spec each phase maps to

2. Explore to Verify Claims

Use Read, Glob, and Grep to check the plan against reality. The point is evidence, not opinion. Examples by lens:

  • A scope item that duplicates code already present in the repo (grep for it)
  • An abstraction, provider layer, or config flag the plan builds for a single case the goals never vary (read the goals — is the generality used?)
  • A hidden dependency on a file, script, or system that does not exist (glob/read for it)
  • A success criterion that names a command or artifact the codebase cannot produce

You may explore, but stay scoped to the contract's claims — do not audit the whole repo.

3. Apply Your Lens

Apply only the charge for the lens you were assigned.

Lens: scope-creep

What scope is unnecessary or belongs at a lower tier for the stated goals? (Structure or machinery inside an in-scope feature is the over-engineering lens's concern, not this one.) Specifically:

Read the full file on GitHub · 143 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 · 143 lines · 54 tokens per session scan A af1c60db4187

Subscribe to this mod's changes

plan-critic is an agent published in the GitHub repository nicknisi/ideation (12 stars, last pushed 5d ago), licensed MIT. It adds 54 tokens to every session and 2,474 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.