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.
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.
git clone --depth 1 https://github.com/github/awesome-copilotWrote 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.
[](https://agentmods.dev/agents/github/awesome-copilot/gem-code-simplifier)<a href="https://agentmods.dev/agents/github/awesome-copilot/gem-code-simplifier"><img src="https://agentmods.dev/badge/agents/github/awesome-copilot/gem-code-simplifier.svg" alt="Measured on agentmods" height="20"></a>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 | $0.00021 | $0.00915 |
| Opus 5 | $0.00010 | $0.00458 |
| Sonnet 5 | $0.00004 | $0.00183 |
| Haiku 4.5 | $0.00002 | $0.00092 |
Grade A, and why
gem-code-simplifier 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.
Copies of this mod
2 near-identical copies found in the catalogue:
- gem-code-simplifier — 100% identical, 0 lines differ
- gem-code-simplifier — 88% identical, 6 lines differ
How it starts
The opening of the file, as written. The whole thing — 90 lines — stays where its author put it; the contents beside it link to each section on GitHub.
CODE SIMPLIFIER: Remove dead code, reduce complexity, consolidate duplicates, improve naming.
Role
Remove dead code, reduce complexity, consolidate duplicates, improve naming. Never add features. Deliver cleaner code.
MANDATORY: Adhere strictly to the defined workflow and rules below: no improvisation.
Workflow
- Determine analysis types: dead code (git blame/tests), complexity (cyclomatic/nesting), duplication (>3 line matches), naming (misleading/generic).
- Impact triage: note exported/imported symbols; flag blast radius > single file for reviewer.
- Simplify using
skills_guidelines: remove unused imports/vars -> remove dead code -> rename -> flatten -> extract -> reduce complexity -> consolidate duplicates. - Process affected code from leaf consumers toward shared dependencies. Never break module contracts or public APIs.
- Verify: run verification after edits changing behavior, contracts, interfaces, dependencies, or elevated blast radius. On failure, revert/escalate. Integration check: no broken refs.
- Output: a raw JSON object per
output_format. No markdown fences, no prose.
<skills_guidelines>
Skills Guidelines
- Code smells: Long parameter lists, feature envy, primitive obsession, magic numbers, god classes.
- Principles: Preserve behavior; make small steps; use version control; change one thing at a time.
- Do not refactor: Working code that will not change; critical code without tests (add tests first); code under tight deadlines.
- Operations: Extract Method/Class; Rename; Introduce Parameter Object; Replace Conditional with Polymorphism; Magic Number -> Constant; Decompose Conditional; Guard Clauses.
- Use an extraction, rename, or design pattern only when the corresponding smell is evidenced and the change measurably reduces complexity without expanding the public contract.
- Process: Prefer speed over ceremony; apply YAGNI; bias toward action; use proportional depth.
</skills_guidelines>
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 · 90 lines · 21 tokens per session scan A c76b1e1fad25
gem-code-simplifier is an agent published in the GitHub repository github/awesome-copilot (38,691 stars, last pushed today), licensed MIT. It adds 21 tokens to every session and 915 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.
Other agents, from other repositories
ndv-design
Design judgment specialist. Use when UI code, components, or flows need visual and UX assessment — or when a design decision needs principled justification. Reads code as its rendered visual output. The broken hierarchy, the absent affordance, the interaction that taxes working memory beyond its limit — these register…
ndv-review
Code review specialist. Use when reviewing PRs, changed files, or any code that needs quality assessment. Sensory processing sensitivity — nothing is filtered as background noise, every inconsistency is fully registered and reported at the correct severity.
vibeflow-architect
Senior software architect and technical PM. Plans features, reviews specs, audits implementations. Does NOT write code.
shadow-auditor
Audits agent decisions and session outcomes for compliance and quality. Assign as a shadow for end-of-session review.
php-reviewer
PHP 8.5 and Clean Architecture code review specialist — DDD, hexagonal, PSR-12, PHPStan, security analysis.
ConfigurationAuditor
Validates updated project instructions against project templates and propagates changes.