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 agentmods add skills/open-gsd/gsd-core/gsd-validate-phasenpx skills add open-gsd/gsd-core --skill gsd-validate-phasegit 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-validate-phase)<a href="https://agentmods.dev/skills/open-gsd/gsd-core/gsd-validate-phase"><img src="https://agentmods.dev/badge/skills/open-gsd/gsd-core/gsd-validate-phase.svg" alt="Measured on agentmods" 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 | $0.00019 | $0.00207 |
| Opus 5 | $0.00010 | $0.00103 |
| Sonnet 5 | $0.00004 | $0.00041 |
| Haiku 4.5 | $0.00002 | $0.00021 |
Grade A, and why
gsd-validate-phase 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 2d 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.
Copies of this mod
4 near-identical copies found in the catalogue:
- thrunt-validate-phase — 88% identical, 18 lines differ
- validate-phase — 88% identical, 11 lines differ
- ferrox-validate-phase — 88% identical, 6 lines differ
- mindforge-validate-phase — 86% identical, 16 lines differ
What it actually says
Output: updated VALIDATION.md + generated test files.
<execution_context> @~/.claude/gsd-core/workflows/validate-phase.md </execution_context>
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.
- 2d ago First seen · 37 lines · 19 tokens per session scan A 9e1c7909c089
gsd-validate-phase is a skill published in the GitHub repository open-gsd/gsd-core (9,140 stars, last pushed today), licensed MIT. It adds 19 tokens to every session and 207 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.
best-practices
Apply modern web development best practices for security, compatibility, and code quality. Use when asked to "apply best practices", "security audit", "modernize code", "code quality review", or "check for vulnerabilities".
core-web-vitals
Optimize Core Web Vitals (LCP, INP, CLS) for better page experience and search ranking. Use when asked to "improve Core Web Vitals", "fix LCP", "reduce CLS", "optimize INP", "page experience optimization", or "fix layout shifts".
gsd-orchestrator
Build software products autonomously via GSD headless mode. Handles the full lifecycle: write a spec, launch a build, poll for completion, handle blockers, track costs, and verify the result. Use when asked to "build something", "create a project", "run gsd", "check build status", or any task that requires autonomous…
gsd-headless
Orchestrate GSD (Git Ship Done) projects programmatically via headless CLI. Use when an agent needs to create milestones from specs, execute dev workflows, monitor progress, check status, or control execution (pause/stop/skip/steer). Triggers on "run gsd", "create milestone", "execute project", "check gsd status"…
api-design
Design or review an HTTP/REST/GraphQL API for versioning, pagination, error shapes, idempotency, auth, status codes, cache headers, and breaking-change management. Use when asked to "design an API", "shape the endpoints", "design the schema", "add a new endpoint", "review this API", or when building/modifying a public…