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.
npx agentmods add skills/addono/gh-attach/create-skillnpx skills add Addono/gh-attach --skill create-skillgit clone --depth 1 https://github.com/Addono/gh-attachWhat 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 | $0.00024 | $0.00648 |
| Opus 5 | $0.00012 | $0.00324 |
| Sonnet 5 | $0.00005 | $0.00130 |
| Haiku 4.5 | $0.00002 | $0.00065 |
Grade A, and why
create-skill 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 yesterday.
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 create-skill — 0 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 — 79 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Create Skill
Guide for creating effective skills that extend agent capabilities with specialized knowledge, workflows, and tool integrations.
About Skills
Skills are modular, self-contained packages that extend agent capabilities by providing specialized knowledge, workflows, and tools. Think of them as "onboarding guides" for specific domains or tasks.
What Skills Provide
- Specialized workflows - Multi-step procedures for specific domains
- Tool integrations - Instructions for working with specific file formats or APIs
- Domain expertise - Company-specific knowledge, schemas, business logic
- Bundled resources - Scripts, references, and assets for complex and repetitive tasks
Progressive Disclosure Principle
The 200-line rule is critical. SKILL.md must be under 200 lines. If you need more, split content into references/ files.
Three-Level Loading System
- Metadata (name + description) - Always in context (~100 words)
- SKILL.md body - When skill triggers (<200 lines, ideally <500 lines for optimal performance)
- Bundled resources - As needed by agent (unlimited)
Why Progressive Disclosure Matters
- 85% reduction in initial context load
- Activation times drop from 500ms+ to under 100ms
- Agent loads only what's needed, when it's needed
- Skills remain maintainable and focused
Skill Structure
skill-name/
├── SKILL.md (required, <200 lines)
│ ├── YAML frontmatter metadata (required)
│ │ ├── name: (required)
│ │ └── description: (required)
│ └── Markdown instructions (required)
└── Bundled Resources (optional)
├── scripts/ - Executable code
├── references/ - Documentation loaded as needed
└── assets/ - Files used in output
Core Principles
Concise is Key
The context window is a shared resource. Your skill shares it with everything else the agent needs. Be concise and challenge each piece of information:
- Does the agent really need this explanation?
- Can I assume the agent knows this?
- Does this paragraph justify its token cost?
What ships with it
7 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- yesterday First seen · 79 lines · 24 tokens per session scan A a88f91120ab8
create-skill is a skill published in the GitHub repository Addono/gh-attach (2 stars, last pushed 20d ago), licensed MIT. It adds 24 tokens to every session and 648 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to create-skill, differing in 0 lines, and is treated as a copy.
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