Borrowing it
Nothing to install: this file belongs to hexxla/mcp-ratchet. 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/hexxla/mcp-ratchet/main/.windsurf/skills/interface-design/SKILL.mdgit clone --depth 1 https://github.com/hexxla/mcp-ratchetWrote 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/skills/hexxla/mcp-ratchet/interface-design)<a href="https://agentmods.dev/skills/hexxla/mcp-ratchet/interface-design"><img src="https://agentmods.dev/badge/skills/hexxla/mcp-ratchet/interface-design/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/hexxla/mcp-ratchet/interface-design"><img src="https://agentmods.dev/badge/skills/hexxla/mcp-ratchet/interface-design.svg" alt="Reviewed on agentmods" width="80" 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 | $0.00011 | $0.00135 |
| Opus 5.5 | $0.00004 | $0.00054 |
| Sonnet 5.5 | $0.00002 | $0.00027 |
| Haiku 4.5 | $0.00001 | $0.00014 |
Grade A, and why
interface-design 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 1mo 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.
What it actually says
Go Interface Design Skill
When reviewing or writing Go code:
- Ensure interfaces are small and focused (single responsibility)
- Validate interfaces are defined by the consumer, not the implementer
- Check that interfaces don't leak implementation details
- Recommend interface composition over large interfaces
- Ensure interfaces are named after behavior (e.g., Reader, Writer)
- Validate that empty interfaces are used only for type assertions
- Check for unnecessary interface abstraction
- Recommend concrete types where interfaces are overkill
- Ensure interface methods are cohesive and related
- Validate that interface changes are backward compatible
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.
- 1mo ago First seen · 20 lines · 11 tokens per session scan A 56fca50aadb3
interface-design is a skill published in the GitHub repository hexxla/mcp-ratchet (2 stars, last pushed 2mo ago), licensed MIT. It adds 11 tokens to every session and 135 once invoked, about $0.0000 per session on Opus 5.5. 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.
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go-proverbs
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