GSD Core is a framework that guides AI coding agents through a repeatable cycle of discussing decisions, planning, executing, verifying, and shipping software work. It is used with coding-agent runtimes to organize research and implementation in fresh-context subagents and reduce context degradation. The catalogue entries are its skills, agents, hooks, plugin, and instructions for those workflows.
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 open-gsd/gsd-core --skill gsd-sketchgit clone --depth 1 https://github.com/open-gsd/gsd-coreWrote 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/open-gsd/gsd-core/gsd-sketch)<a href="https://agentmods.dev/skills/open-gsd/gsd-core/gsd-sketch"><img src="https://agentmods.dev/badge/skills/open-gsd/gsd-core/gsd-sketch/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/open-gsd/gsd-core/gsd-sketch"><img src="https://agentmods.dev/badge/skills/open-gsd/gsd-core/gsd-sketch.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 1 finding, 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 Rogue Agent · line 7 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 | $0.00027 | $0.00581 |
| Opus 5 | $0.00014 | $0.00291 |
| Sonnet 5 | $0.00005 | $0.00116 |
| Haiku 4.5 | $0.00003 | $0.00058 |
Grade A, and why
gsd-sketch 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.
What it actually says
Two modes:
- Idea mode (default) — describe a design idea to sketch
- Frontier mode (no argument or "frontier") — analyzes existing sketch landscape and proposes consistency and frontier sketches
Does not require prior new-project setup — auto-creates .planning/sketches/ if needed.
<execution_context>
@/.claude/gsd-core/workflows/sketch.md
@/.claude/gsd-core/workflows/sketch-wrap-up.md
@/.claude/gsd-core/references/ui-brand.md
@/.claude/gsd-core/references/sketch-theme-system.md
@/.claude/gsd-core/references/sketch-interactivity.md
@/.claude/gsd-core/references/sketch-tooling.md
@~/.claude/gsd-core/references/sketch-variant-patterns.md
</execution_context>
<runtime_note>
Copilot (VS Code): Use vscode_askquestions wherever this workflow calls AskUserQuestion.
</runtime_note>
Available flags:
--quick— Skip mood/direction intake, jump straight to decomposition and building. Use when the design direction is already clear.--wrap-up— Package sketch design findings into a persistent project skill for future build conversations. Runs the sketch-wrap-up workflow.
Preserve all workflow gates (intake, decomposition, target stack research, variant evaluation, MANIFEST updates, commit patterns).
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 · 61 lines · 27 tokens per session scan A 11ef7d436090
gsd-sketch is a skill published in the GitHub repository open-gsd/gsd-core (9,278 stars, last pushed today), licensed MIT. It adds 27 tokens to every session and 581 once invoked, about $0.0001 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.
Other skills, from other repositories
userinterface-wiki
UI/UX best practices for web interfaces. Use when reviewing animations, CSS, audio, typography, UX patterns, prefetching, or icon implementations. Covers 11 categories from animation principles to typography. Outputs file:line findings.
web-design-guidelines
Review UI code for Web Interface Guidelines compliance. Use when asked to "review my UI", "check accessibility", "audit design", "review UX", or "check my site against best practices".
make-interfaces-feel-better
Design-engineering principles for making interfaces feel polished. Use when building UI components or doing visual detail work — animations, hover states, shadows, borders, typography, micro-interactions. Triggers on "make it feel better", "feels off", stagger animations, border radius, optical alignment, font…
frontend-design
Create distinctive, production-grade frontend interfaces with high design quality. Use this skill when the user asks to build web components, pages, artifacts, posters, or applications (examples include websites, landing pages, dashboards, React components, HTML/CSS layouts, or when styling/beautifying any web UI).…
web-quality-audit
Comprehensive web quality audit covering performance, accessibility, SEO, and best practices. Use when asked to "audit my site", "review web quality", "run lighthouse audit", "check page quality", or "optimize my website".
accessibility
Audit and improve web accessibility following WCAG 2.1 guidelines. Use when asked to "improve accessibility", "a11y audit", "WCAG compliance", "screen reader support", "keyboard navigation", or "make accessible".