Borrowing it
Nothing to install: this file belongs to JimmyPaolini/codebase. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/JimmyPaolini/codebase/main/.github/instructions/agent-skills.instructions.mdgit clone --depth 1 https://github.com/JimmyPaolini/codebaseWrote 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/instructions/jimmypaolini/codebase/agent-skills)<a href="https://agentmods.dev/instructions/jimmypaolini/codebase/agent-skills"><img src="https://agentmods.dev/badge/instructions/jimmypaolini/codebase/agent-skills.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 | $0.02633 | $0.02633 |
| Opus 5 | $0.01316 | $0.01316 |
| Sonnet 5 | $0.00527 | $0.00527 |
| Haiku 4.5 | $0.00263 | $0.00263 |
Grade A, and why
codebase agent-skills.instructions.md 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 4d 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.
This is a copy
100% identical to custom_github_copilot_agent_builder agent-skills.instructions.md — 113 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 273 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Agent Skills File Guidelines
Instructions for creating effective and portable Agent Skills that enhance GitHub Copilot with specialized capabilities, workflows, and bundled resources.
What Are Agent Skills?
Agent Skills are self-contained folders with instructions and bundled resources that teach AI agents specialized capabilities. Unlike custom instructions (which define coding standards), skills enable task-specific workflows that can include scripts, examples, templates, and reference data.
Key characteristics:
- Portable: Works across VS Code, Copilot CLI, and Copilot coding agent
- Progressive loading: Only loaded when relevant to the user's request
- Resource-bundled: Can include scripts, templates, examples alongside instructions
- On-demand: Activated automatically based on prompt relevance
Directory Structure
Skills are stored in specific locations:
| Location | Scope | Recommendation |
|---|---|---|
.github/skills/<skill-name>/ |
Project/repository | Recommended for project skills |
.claude/skills/<skill-name>/ |
Project/repository | Legacy, for backward compatibility |
~/.github/skills/<skill-name>/ |
Personal (user-wide) | Recommended for personal skills |
~/.claude/skills/<skill-name>/ |
Personal (user-wide) | Legacy, for backward compatibility |
Each skill must have its own subdirectory containing at minimum a SKILL.md file.
Required SKILL.md Format
Frontmatter (Required)
---
name: webapp-testing
description: Toolkit for testing local web applications using Playwright. Use when asked to verify frontend functionality, debug UI behavior, capture browser screenshots, check for visual regressions, or view browser console logs. Supports Chrome, Firefox, and WebKit browsers.
license: Complete terms in LICENSE.txt
---
| Field | Required | Constraints |
|---|---|---|
name |
Yes | Lowercase, hyphens for spaces, max 64 characters (e.g., webapp-testing) |
description |
Yes | Clear description of capabilities AND use cases, max 1024 characters |
license |
No | Reference to LICENSE.txt (e.g., Complete terms in LICENSE.txt) or SPDX identifier |
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.
- 4d ago First seen · 273 lines · 2,633 tokens per session scan A 8bf4bd672e2a
codebase agent-skills.instructions.md is an instructions file published in the GitHub repository JimmyPaolini/codebase (0 stars, last pushed today), licensed MIT. It adds 2,633 tokens to every session, about $0.0132 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to custom_github_copilot_agent_builder agent-skills.instructions.md, differing in 113 lines, and is treated as a copy.
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