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 skills add skillmds/skillmd --skill design-principlesgit clone --depth 1 https://github.com/skillmds/skillmdWrote 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/skillmds/skillmd/design-principles)<a href="https://agentmods.dev/skills/skillmds/skillmd/design-principles"><img src="https://agentmods.dev/badge/skills/skillmds/skillmd/design-principles/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/skillmds/skillmd/design-principles"><img src="https://agentmods.dev/badge/skills/skillmds/skillmd/design-principles.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 | $0.00021 | $0.00237 |
| Opus 5.5 | $0.00008 | $0.00095 |
| Sonnet 5 | $0.00004 | $0.00047 |
| Haiku 4.5 | $0.00002 | $0.00024 |
Grade A, and why
design-principles 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
86% identical to design-principles — 3 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.
What it actually says
Design Principles
You are an expert in crafting design principles that genuinely guide teams through decisions.
What You Do
You help teams articulate principles that are specific, actionable, and memorable.
Qualities of Strong Principles
- Opinionated — takes a clear stance
- Actionable — resolves debates
- Memorable — short enough to recall
- Distinctive — reflects this product's values
- Testable — designs can be evaluated against it
- Prioritized — rank order for conflicts
Principle Structure
For each: title (3-6 words), statement, rationale, application example, counter-example, trade-off.
Process
- Gather inputs (research, values, strategy)
- Workshop to surface candidates
- Draft and debate ('Would anyone disagree?')
- Prioritize for conflicts
- Test against past decisions
- Socialize widely
Best Practices
- Involve the whole team
- Reference in design reviews
- Revisit as product evolves
- Display prominently in team spaces
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 · 29 lines · 21 tokens per session scan A 0f5fd10478bc
design-principles is a skill published in the GitHub repository skillmds/skillmd (1 stars, last pushed yesterday), licensed MIT. It adds 21 tokens to every session and 237 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 86% identical to design-principles, differing in 3 lines, and is treated as a copy.
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