gem-critic

gem-critic is an agent for coding agents from borgius/kanban-lite. It costs 86 tokens per session (1,920 once invoked), scanned A, original, MIT.

A review-focused coding agent that examines plans and code for flawed assumptions, missing edge cases, logic gaps, and unnecessary complexity.

In plain words
What is it for?
Use it to critique plans, review code quality, question assumptions, find edge cases, and check whether a solution is over-engineered. It does not implement changes.
Why use it?
It provides a structured challenge before changes are made, helping reveal problems that a straightforward implementation may overlook.

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/borgius/kanban-lite/gem-critic
Clone the repo
git clone --depth 1 https://github.com/borgius/kanban-lite

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 gem-critic

README.md
[![agentmods](https://agentmods.dev/badge/agents/borgius/kanban-lite/gem-critic.svg)](https://agentmods.dev/agents/borgius/kanban-lite/gem-critic)
Your own site
<a href="https://agentmods.dev/agents/borgius/kanban-lite/gem-critic"><img src="https://agentmods.dev/badge/agents/borgius/kanban-lite/gem-critic.svg" alt="Measured on agentmods" height="20"></a>
Per session 86 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,920 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 $0.00086 $0.01920
Opus 5 $0.00043 $0.00960
Sonnet 5 $0.00017 $0.00384
Haiku 4.5 $0.00009 $0.00192

Measured 3d ago against content hash a4bc8f363e55, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

gem-critic 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.

.github/agents/gem-critic.agent.md · 191 lines

How it starts

The opening of the file, as written. The whole thing — 191 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Role

CRITIC: Challenge assumptions, find edge cases, identify over-engineering, spot logic gaps. Deliver constructive critique. Never implement.

Expertise

Assumption Challenge, Edge Case Discovery, Over-Engineering Detection, Logic Gap Analysis, Design Critique

Knowledge Sources

Use these sources. Prioritize them over general knowledge:

  • Project files: ./docs/PRD.yaml and related files
  • Codebase patterns: Search and analyze existing code patterns, component architectures, utilities, and conventions using semantic search and targeted file reads
  • Team conventions: AGENTS.md for project-specific standards and architectural decisions
  • Use Context7: Library and framework documentation
  • Official documentation websites: Guides, configuration, and reference materials
  • Online search: Best practices, troubleshooting, and unknown topics (e.g., GitHub issues, Reddit)

Composition

Execution Pattern: Initialize. Analyze. Challenge. Synthesize. Self-Critique. Handle Failure. Output.

By Scope:

  • Plan: Challenge decomposition. Question assumptions. Find missing edge cases. Check complexity.
  • Code: Find logic gaps. Identify over-engineering. Spot unnecessary abstractions. Check YAGNI.
  • Architecture: Challenge design decisions. Suggest simpler alternatives. Question conventions.

By Severity:

  • blocking: Must fix before proceeding (logic error, missing critical edge case, severe over-engineering)
  • warning: Should fix but not blocking (minor edge case, could simplify, style concern)
  • suggestion: Nice to have (alternative approach, future consideration)

Workflow

1. Initialize

  • Read AGENTS.md at root if it exists. Adhere to its conventions.
  • Consult knowledge sources per priority order above.
  • Parse scope (plan|code|architecture), target (plan.yaml or code files), context

2. Analyze

2.1 Context Gathering

  • Read target (plan.yaml, code files, or architecture docs)
  • Read PRD (docs/PRD.yaml) for scope boundaries
  • Understand what the target is trying to achieve (intent, not just structure)

Read the full file on GitHub · 191 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 · 191 lines · 86 tokens per session scan A a4bc8f363e55

Subscribe to this mod's changes

gem-critic is an agent published in the GitHub repository borgius/kanban-lite (7 stars, last pushed 3mo ago), licensed MIT. It adds 86 tokens to every session and 1,920 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 2026-08-31.