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 btspoony/mstar-harness --skill mstar-design-systemgit clone --depth 1 https://github.com/btspoony/mstar-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/btspoony/mstar-harness/mstar-design-system)<a href="https://agentmods.dev/skills/btspoony/mstar-harness/mstar-design-system"><img src="https://agentmods.dev/badge/skills/btspoony/mstar-harness/mstar-design-system/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/btspoony/mstar-harness/mstar-design-system"><img src="https://agentmods.dev/badge/skills/btspoony/mstar-harness/mstar-design-system.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 | $0.00081 | $0.01184 |
| Opus 5.5 | $0.00032 | $0.00474 |
| Sonnet 5.5 | $0.00016 | $0.00237 |
| Haiku 4.5 | $0.00008 | $0.00118 |
Grade A, and why
mstar-design-system 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 today.
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 — 63 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Load Order
Before the first Read of this skill: Read mstar-harness-core (SKILL.md) — lifecycle, authorization, and conflict authority. The design contract, when the baseline is a written contract, is owned by mstar-design-md; this skill assumes an authoritative baseline exists and defers that contract's authority and sync direction to it; this skill does not restate those.
| Also Read | When |
|---|---|
mstar-design-md |
any difference touches tokens, completeness levels, light/dark, or the baseline-vs-document authority rule |
mstar-coding-behavior |
the round ends in code changes rather than document changes |
On conflict, mstar-harness-core wins; on a design-contract question, mstar-design-md wins.
Scope
In scope: an authority already exists and an implementation has to be converged onto it — locating and making the baseline readable, deriving the machine-readable fixture, measuring parity per layer, triaging each difference, closing it in one direction, and reporting what was actually compared.
| Out of scope | Where it belongs |
|---|---|
| Designing a system where no baseline exists | not this skill — decide the contract first |
DESIGN.md sections, token naming, completeness levels, light/dark rules |
mstar-design-md |
| Prototype-vs-document authority and its one-directional sync | mstar-design-md § Prototype vs document — read it there; this skill only applies it |
| The comparators, CI jobs, and generators of a specific repository | that repository's own checks |
Workflow
- Baseline — name the authority: its kind, its location, whether it is readable and tracked, and what was redacted before it was committed. No baseline → stop, this skill does not apply.
- Machine — derive what can be derived instead of typing it: fixture, snapshot, extraction. Record the regeneration command and its check mode in the same place.
- Parity — compare per layer: structure, appearance, behaviour. Every finding carries the count it was measured on; a probe that matched nothing says so instead of reporting zero defects.
- Triage — classify every difference as defect, decision, or phantom. A decision is written into the contract record with its reason, never silently into the implementation.
- Close — change the implementation, or amend the baseline when triage recorded a decision.
- Evidence — return what
## Evidencebelow describes; a verdict without its counts is not one.
What ships with it
3 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.
- today First seen · 63 lines · 81 tokens per session scan A 7922970d5684
mstar-design-system is a skill published in the GitHub repository btspoony/mstar-harness (64 stars, last pushed today), licensed MIT. It adds 81 tokens to every session and 1,184 once invoked, about $0.0003 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 2026-10-28.
Other skills, from other repositories
planr-design
Run OpenPlanr design, design-loop, or design-review using portable board assets.
frontend-design
Guidance for distinctive, intentional visual design when building new UI or reshaping an existing one. Helps with aesthetic direction, typography, and making choices that don't read as templated defaults.
subagent-driven-development
Use when executing implementation plans with independent tasks in the current session.
comet
Comet — OpenSpec + Superpowers dual-star development workflow. Start with /comet for automatic phase detection and dispatch to subcommands. Five phases: open → design → build → verify → archive.
comet-classic
A Chinese-language workflow guide for starting or resuming a structured software change using OpenSpec and Superpowers.
comet-design
Comet Phase 2: Deep Design. Invoke with /comet-design. Produce Design Doc and delta spec through brainstorming.