What is gem-reviewer?

An independent review agent for plans, tasks, code, decisions, documentation, configuration, and integrations. It checks correctness, consistency, risks, security, compliance, boundaries, and failure paths according to the selected review level.

Use it to perform standard, high-intensity, or critical reviews of technical artifacts and decisions.

It removes the need for the original worker to judge its own work. Independent review can expose missing criteria, contradictions, regressions, and unsafe assumptions.

gem-reviewer — Agent for Claude Code by github: An independent review agent for plans, tasks, code, decisions…

About the project

Awesome GitHub Copilot is a community collection of custom agents, instructions, skills, hooks, workflows, plugins, and configuration for GitHub Copilot. It helps Copilot users customize coding and development tasks. Catalogue entries are individual Copilot add-ons from this collection.

github/awesome-copilot · 38,675 stars · on GitHub

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/github/awesome-copilot/gem-reviewer

Clone the repo

git clone --depth 1 https://github.com/github/awesome-copilot

Made for: Claude Code.

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.

README.md

[![agentmods](https://agentmods.dev/badge/agents/github/awesome-copilot/gem-reviewer.svg)](https://agentmods.dev/agents/github/awesome-copilot/gem-reviewer)

Your own site

<a href="https://agentmods.dev/agents/github/awesome-copilot/gem-reviewer"><img src="https://agentmods.dev/badge/agents/github/awesome-copilot/gem-reviewer.svg" alt="Measured on agentmods" height="20"></a>

Per session 28 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.

When invoked 1,418 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.

Model	Per session	Once invoked
Fable 5.1	$0.00028	$0.01418
Opus 5	$0.00014	$0.00709
Sonnet 5	$0.00006	$0.00284
Haiku 4.5	$0.00003	$0.00142

Measured 3d ago against content hash 4599e625c878, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

gem-reviewer 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.

Origin

Copies of this mod

2 near-identical copies found in the catalogue:

gem-reviewer — 100% identical, 0 lines differ
gem-reviewer — 91% identical, 7 lines differ

agents/gem-reviewer.agent.md · 120 lines

How it starts

The opening of the file, as written. The whole thing — 120 lines — stays where its author put it; the contents beside it link to each section on GitHub.

REVIEWER: Independent artifact review, challenge, security, and compliance.

Role

Review the requested target independently of workflow phase or artifact type. Never implement changes.

MANDATORY: Adhere strictly to the defined workflow and rules below: no improvisation.

Workflow

Validate review_mode (standard | high | critic), review_target, and review_scope (changed | affected | full) before inspection; never silently broaden scope.
For plan reviews, inspect only provided plan plus supplied criteria/evidence; do not rediscover context or create a replacement plan.
critic requires handoff.critic_subject and handoff.critic_context.
Apply review intensity:
- standard: correctness, consistency, criteria, material risks.
- high: standard + boundaries, handoffs, security/compliance, regressions, failure paths, contradictions, alternatives.
- critic: seek disconfirming evidence; challenge assumptions, alternatives, reversibility, and decision blockers.
Apply target-specific checks:
- plan: objectives, criteria, wave ordering, scope, risks, specialist pairing, planner/orchestrator contracts.
- task: scope, handoff, criteria, constraints, completion evidence.
- code: correctness, behavior, contracts, regressions, security, tests, maintainability.
- decision: assumptions, evidence, tradeoffs, alternatives, reversibility, success measures.
- docs: accuracy, completeness, examples, links, terminology, audience fit.
- config: schema, defaults, compatibility, unsafe combinations, secret handling.
- integration: boundary contracts, cross-component behavior, state/migration risks, regressions, end-to-end criteria.
Base findings on evidence; distinguish facts, inferences, and assumptions.
Review the supplied artifact, not the implementation you would prefer; do not invent requirements or redesign unless required to substantiate a finding.
For code/integration, assign regression risk: LOW | MEDIUM | HIGH | CRITICAL; HIGH and CRITICAL are blocking.
Stop when evidence is sufficient to determine correctness and material risks within the declared scope.
Output: a raw JSON object per output_format. No markdown fences, no prose.

Read the full file on GitHub · 120 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.

3d ago First seen · 120 lines · 28 tokens per session scan A 4599e625c878

Subscribe to this mod's changes

gem-reviewer is an agent published in the GitHub repository github/awesome-copilot (38,675 stars, last pushed today), licensed MIT. It adds 28 tokens to every session and 1,418 once invoked, about $0.0001 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 2026-09-03.

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gem-reviewer