GSD Pi is a command-line coding agent and project workflow system that plans, implements, verifies, and tracks software work through milestones, tasks, Git worktrees, and stored project notes. It is for developers who want structured, longer-running agent sessions using different model providers. The catalogue entries extend GSD Pi with skills and agents.
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-pi/create-skillnpx skills add open-gsd/gsd-pi --skill create-skillgit clone --depth 1 https://github.com/open-gsd/gsd-piWrote 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-pi/create-skill)<a href="https://agentmods.dev/skills/open-gsd/gsd-pi/create-skill"><img src="https://agentmods.dev/badge/skills/open-gsd/gsd-pi/create-skill.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 | $0.00045 | $0.01513 |
| Opus 5 | $0.00023 | $0.00757 |
| Sonnet 5 | $0.00009 | $0.00303 |
| Haiku 4.5 | $0.00005 | $0.00151 |
Grade A, and why
create-skill 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 5d 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 — 193 lines — stays where its author put it; the contents beside it link to each section on GitHub.
<essential_principles>
How Skills Work
Skills are modular, filesystem-based capabilities that provide domain expertise on demand. This skill teaches how to create effective skills.
1. Skills Are Prompts
All prompting best practices apply. Be clear, be direct, use XML structure. Assume Claude is smart - only add context Claude doesn't have.
2. SKILL.md Is Always Loaded
When a skill is invoked, Claude reads SKILL.md. Use this guarantee:
- Essential principles go in SKILL.md (can't be skipped)
- Workflow-specific content goes in workflows/
- Reusable knowledge goes in references/
3. Router Pattern for Complex Skills
skill-name/
├── SKILL.md # Router + principles
├── workflows/ # Step-by-step procedures (FOLLOW)
├── references/ # Domain knowledge (READ)
├── templates/ # Output structures (COPY + FILL)
└── scripts/ # Reusable code (EXECUTE)
SKILL.md asks "what do you want to do?" → routes to workflow → workflow specifies which references to read.
When to use each folder:
- workflows/ - Multi-step procedures Claude follows
- references/ - Domain knowledge Claude reads for context
- templates/ - Consistent output structures Claude copies and fills (plans, specs, configs)
- scripts/ - Executable code Claude runs as-is (deploy, setup, API calls)
4. Pure XML Structure
No markdown headings (#, ##, ###) in skill body. Use semantic XML tags:
<objective>...</objective>
<process>...</process>
<success_criteria>...</success_criteria>
Keep markdown formatting within content (bold, lists, code blocks).
5. Progressive Disclosure
SKILL.md under 500 lines. Split detailed content into reference files. Load only what's needed for the current workflow. </essential_principles>
Based on the user's message, route directly to the appropriate workflow:
Creating new skills:
- Domain expertise (exhaustive knowledge base) → Use
create-domain-expertiseskill instead (separate skill with batched subagent orchestration) - Task-execution skill (does specific things) → workflows/create-new-skill.md
What ships with it
24 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.
- references/api-security.md 6.0 KB
- references/be-clear-and-direct.md 13 KB
- references/common-patterns.md 14 KB
- references/core-principles.md 12 KB
- references/executable-code.md 4.3 KB
- references/gsd-skill-ecosystem.md 3.4 KB
- references/iteration-and-testing.md 13 KB
- references/recommended-structure.md 3.9 KB
- references/skill-structure.md 11 KB
- references/use-xml-tags.md 11 KB
- references/using-scripts.md 3.0 KB
- references/using-templates.md 2.9 KB
- references/workflows-and-validation.md 12 KB
- templates/router-skill.md 1.5 KB
- templates/simple-skill.md 636 B
- workflows/add-reference.md 2.5 KB
- workflows/add-script.md 2.3 KB
- workflows/add-template.md 2.1 KB
- workflows/add-workflow.md 3.1 KB
- workflows/audit-skill.md 3.6 KB
- workflows/create-new-skill.md 6.0 KB
- workflows/get-guidance.md 3.0 KB
- workflows/upgrade-to-router.md 4.0 KB
- workflows/verify-skill.md 5.5 KB
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.
- 5d ago First seen · 193 lines · 45 tokens per session scan A 8d646d9246b2
create-skill is a skill published in the GitHub repository open-gsd/gsd-pi (1,196 stars, last pushed yesterday), licensed MIT. It adds 45 tokens to every session and 1,513 once invoked, about $0.0002 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 2026-08-30.
Other skills, from other repositories
gsd-complete-milestone
Archive completed milestone and prepare for next version.
gsd-discuss-phase
Gather phase context through adaptive questioning before planning.
gsd-debug
Systematic debugging with persistent state across context resets.
gsd-capture
Capture ideas, tasks, notes, and seeds to their destination.
gsd-code-review
Review source files changed during a phase for bugs, security issues, and code quality problems.
gsd-config
Configure GSD settings — workflow toggles, advanced knobs, integrations, and model profile.