# Deliver Edge Cases (agent 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.

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.

## Key facts

| Fact | Value |
|---|---|
| Repository | https://github.com/product-on-purpose/pm-skills |
| Skill path | skills/deliver-edge-cases/SKILL.md |
| Skill name | deliver-edge-cases |
| GitHub stars | 713 |
| Installs on skills.sh | not listed |
| License | Apache-2.0 |
| Skills in repo | 1 |
| Plugin marketplace | pm-skills-marketplace |
| Official | no |
| Works with | Claude Code, Codex, Cursor, Gemini CLI, GitHub Copilot, OpenCode |
| Category | Testing & QA |
| Last commit | Sep 10, 2026 |

## Add this skill

### Claude Code

```sh
/plugin marketplace add product-on-purpose/pm-skills
/plugin install pm-skills@pm-skills-marketplace
```

In the Claude apps, zip the skill folder and upload it under Customize > Skills > + > Upload a skill (code execution must be on).

### ChatGPT / Codex

```sh
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 projects
```

### Cursor

```sh
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 projects
```

Sources (checked 2026-10-07): https://code.claude.com/docs/en/skills, https://support.claude.com/en/articles/12512180-using-skills-in-claude, https://learn.chatgpt.com/docs/build-skills, https://cursor.com/docs/context/skills

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Canonical page: https://appsgit.com/skills/product-on-purpose-deliver-edge-cases
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