Custom GPT build kit for GStack Strategy 21: a product and engineering operating partner that turns vague ideas into scoped, testable, GitHub-ready work.
Repository name: gstack-gpt
Keywords: custom-gpt, gpt-builder, strategy21, product-strategy, engineering-planning, github-workflows, decision-memos, release-gates, issue-generation, claude-skills, prompt-engineering.
This repo now folds in the strategy-skill map from aapersh/strategy-skills-for-claude, via the maintained fork at ryan-winkler/strategy-skills-for-claude.
The imported skills are kept as source reference under references/strategy-skills-for-claude/. GStack Strategy 21 uses them as a strategy backbone, then turns the work into product and engineering artifacts: build briefs, GitHub issues, decision memos, release gates, roadmap choices, and review checklists.
Use the ChatGPT GPT Builder Configure form. Do not paste YAML or this README into the Instructions field.
- Open the GPT editor.
- Fill the fields from
builder-form.md. - Paste only
instructions.mdinto Instructions. - Upload
knowledge/strategy-21-reference.mdunder Knowledge. - Turn on the recommended capabilities from
builder-form.md. - Test with
test-prompts.mdin Preview. - Create or Update the GPT.
| File | Use |
|---|---|
builder-form.md |
Field-by-field GPT Builder values |
instructions.md |
Copy this into the GPT Instructions field |
knowledge/strategy-21-reference.md |
Upload this as GPT Knowledge |
references/strategy-skills-for-claude/ |
Source reference from the forked strategy skills repo |
test-prompts.md |
Preview prompts and expected behaviors |
llms.txt |
Machine-readable project summary for discovery |
GStack Strategy 21 helps a founder, PM, or builder convert fuzzy product and engineering ideas into useful work artifacts:
- product bets
- sharper user jobs
- scoped build briefs
- GitHub issue bodies
- PR review checklists
- release gates
- reusable decision notes
- retro follow-ups
It is intentionally biased toward small, reversible, evidence-backed changes. It should challenge vague strategy, narrow ocean-sized work, preserve the language of the product area, and leave behind reusable artifacts that get better after every launch.
This is not a documentation starter, an app runtime, or a custom Actions server.
Actions are left off by default. Use the GitHub App capability if your GPT workspace exposes it. Add custom Actions only when you have a real external API and an OpenAPI schema.
- GStack upstream: https://github.com/garrytan/gstack
- GStack GPT home: https://github.com/ryan-winkler/gstack-gpt
- Strategy skills upstream: https://github.com/aapersh/strategy-skills-for-claude
- Strategy skills fork: https://github.com/ryan-winkler/strategy-skills-for-claude
- Fork lineage: https://github.com/aapersh/strategy-skills-for-claude -> https://github.com/ryan-winkler/strategy-skills-for-claude
- Ryan Winkler public profile and writing context: https://github.com/ryan-winkler/ryanwinkler
- GStack: https://gstack.lol/
- GStack repository: https://github.com/garrytan/gstack
- GStack-GPT origin: https://github.com/ryan-winkler/gstack-gpt
- Strategy skills fork: https://github.com/ryan-winkler/strategy-skills-for-claude
- Strategy skills upstream: https://github.com/aapersh/strategy-skills-for-claude
- Ryan Winkler: https://github.com/ryan-winkler/ryanwinkler
- GPT Builder help: https://help.openai.com/en/articles/8554397-creating-and-editing-gpts
- GPT editor entry: https://chatgpt.com/gpts
@garrytan @aapersh