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 ericrisco/rsc-harness --skill design-dnagit clone --depth 1 https://github.com/ericrisco/rsc-harnessWrote 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/ericrisco/rsc-harness/design-dna)<a href="https://agentmods.dev/skills/ericrisco/rsc-harness/design-dna"><img src="https://agentmods.dev/badge/skills/ericrisco/rsc-harness/design-dna/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/ericrisco/rsc-harness/design-dna"><img src="https://agentmods.dev/badge/skills/ericrisco/rsc-harness/design-dna.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 2 findings, up to medium
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- medium MCP Rug Pull · line 29 npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.Fix: Pin the version: npx @scope/[email protected]
- medium Rogue Agent · line 75 Skill establishes unauthorized persistence across sessions via cron jobs, startup scripts, or state files. Session persistence allows an attacker to maintain access beyond the current interaction.Fix: Remove any persistence mechanisms (cron jobs, startup scripts, state files). Skills should not maintain state across sessions without explicit user consent.
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 | $0.00086 | $0.02994 |
| Opus 5 | $0.00043 | $0.01497 |
| Sonnet 5 | $0.00017 | $0.00599 |
| Haiku 4.5 | $0.00009 | $0.00299 |
Grade A, and why
design-dna 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 6d 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.
How it starts
The opening of the file, as written. The whole thing — 163 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Design DNA - one beautiful design into a permanent skill
A design loop finds you one beautiful thing. This turns that one thing into a skill you keep forever, so you can make more of it, in any format, without the look drifting.
Not only about "designs". The subject is anything that got built: a website, a landing page, a poster, a motion graphic, a carousel, a deck. Same system, same file, same tests. The format is an output, not the subject.
The problem this solves
Nobody wrote down why the winner was beautiful. Next time you ask for "the same style" you get something close, then something a bit off, then something generic. Every rule you do not write down, the model has to guess, and it does not guess randomly: it guesses the average of everything it has ever seen. That average is what people call slop. Slop is the sound of an unwritten rule.
Two modes
| You say | Mode | What happens |
|---|---|---|
| "codify this", "turn this into a skill", here is the winner | CAPTURE | Run the seven steps below. Output: a new style skill folder. |
"build X in ", "another one like the last", /<slug> |
REUSE | Load that style's PROMPT.md only, build, then run its self-check before returning. |
If a dna.json already exists for the style named, you are in REUSE. Never re-derive a style that has a record.
To find out which records exist — in either scope, without guessing at paths — run
npx @ericrisco/rsc doctor --json and read designStartingPoint. A record it reports as unreadable
is not a record you can reuse: say what is missing, do not use half of one.
Hard rules (these are the skill)
- A specification that cannot fail is not a specification. If every rule you wrote is one a bad output could still satisfy, you wrote a mood board.
- Compile, do not paste. Two files, always.
dna.jsonis the record, any size, and it never enters a prompt.PROMPT.mdis the payload, hard cap 2KB, and it is the only thing that does. - Always attach the reference image. Highest-leverage move available and close to free: image conditioning runs on its own pathway, so it does not eat the attention your words are competing for.
- Ratios, not values. "The headline is 96px" is nearly worthless. "The headline is 8x the body, never under 6x" is the identity.
- Coverage, not just colour. The same three hex codes at 60/30/10 and at 90/8/2 are two unrelated designs.
- Percentages, not pixels, in everything spatial. One spec has to drive a 1080x1350 carousel and a 1920x1080 slide with no rewrite.
- When output looks generic, add a ban, not a rule. A positive instruction is one weak vote against a landslide; "never centre the hero" deletes the landslide from the options. Bans should outnumber positive style rules.
- One skill per style. Never merge two identities into one spec. The average of two good designs is a bad design.
- Reproduce the system, never the marks. Real logos, wordmarks, licensed photographs and proprietary typefaces go in
meta.not_copiedwith a named substitute. - Step 5 is not optional. A spec that has never been used to rebuild its own source has never been tested.
What ships with it
9 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.
- 6d ago First seen · 163 lines · 86 tokens per session scan A bb71393d6c28
design-dna is a skill published in the GitHub repository ericrisco/rsc-harness (78 stars, last pushed today), licensed MIT. It adds 86 tokens to every session and 2,994 once invoked, about $0.0004 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.
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