Deliver Edge Cases
Deliver Edge Cases is an agent skill (a SKILL.md file) from product-on-purpose/pm-skills. Documents edge cases, error states, boundary conditions, race conditions, and recovery paths for a feature - the systematic catalog of what can go wrong and the failure modes… It works with Claude Code, Codex, Cursor, Gemini CLI, GitHub Copilot and OpenCode and has 713 GitHub stars.
github.com/product-on-purpose/pm-skills/skills/deliver-edge-cases (opens in a new tab)
- Plugin marketplace
- Testing & QA
- Actively maintained
Add this skill
Claude
This repository is a Claude Code plugin marketplace. In Claude Code:
/plugin marketplace add product-on-purpose/pm-skills
/plugin install pm-skills@pm-skills-marketplaceIn the Claude apps, zip the deliver-edge-cases folder and upload it under Customize > Skills > + > Upload a skill (code execution must be on).
ChatGPT / Codex
Codex reads skills from .agents/skills/ in a repo or ~/.agents/skills/ for every project:
git clone --depth 1 https://github.com/product-on-purpose/pm-skills.git
cp -r pm-skills/skills/deliver-edge-cases .agents/skills/deliver-edge-cases # repo; ~/.agents/skills for all projectsStandalone skills also load in the ChatGPT desktop app.
Cursor
Cursor loads skills from .cursor/skills/ (or ~/.cursor/skills/) and also reads .claude/skills/:
git clone --depth 1 https://github.com/product-on-purpose/pm-skills.git
cp -r pm-skills/skills/deliver-edge-cases .cursor/skills/deliver-edge-cases # project; ~/.cursor/skills for all projectsSource (checked Oct 7, 2026): code.claude.com/docs/en/skills (opens in a new tab), code.claude.com/docs/en/plugin-marketplaces (opens in a new tab), support.claude.com/en/articles/12512180-using-skills-in-claude (opens in a new tab), learn.chatgpt.com/docs/build-skills (opens in a new tab), cursor.com/docs/context/skills (opens in a new tab)
What this skill does
Documents edge cases, error states, boundary conditions, race conditions, and recovery paths for a feature - the systematic catalog of what can go wrong and the failure modes to design for. Use during specification to map the failure surface and ensure comprehensive coverage, or during QA planning to identify boundary and limit scenarios to test. Distinct from deliver-acceptance-criteria, which writes story-level Given/When/Then checks; this skill produces the whole-feature edge-case catalog.
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What is the Deliver Edge Cases skill?
Deliver Edge Cases is an agent skill (a SKILL.md file) from product-on-purpose/pm-skills. Documents edge cases, error states, boundary conditions, race conditions, and recovery paths for a feature - the systematic catalog of what can go wrong and the failure modes… It works with Claude Code, Codex, Cursor, Gemini CLI, GitHub Copilot and OpenCode and has 713 GitHub stars. Its SKILL.md lives at github.com/product-on-purpose/pm-skills/skills/deliver-edge-cases.
How do I install the Deliver Edge Cases skill?
In Claude Code, run /plugin marketplace add product-on-purpose/pm-skills and then /plugin install pm-skills@pm-skills-marketplace. For Codex or Cursor, copy the deliver-edge-cases folder into .agents/skills/ or .cursor/skills/.
Is the Deliver Edge Cases skill free?
Yes. The repository is open source under the Apache-2.0 license.
Is Deliver Edge Cases maintained?
The repository's most recent commit was on Sep 10, 2026. Its latest release is v2.33.0. appsgit only lists skills from repositories with a commit in the last six months.