User Story Writer
deanpeters/Product-Manager-Skills
Writes user stories in Mike Cohn's format with Gherkin acceptance criteria, turning user needs into development-ready work with testable conditions.
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.
Install Deliver Edge Cases
$ npx skills add product-on-purpose/pm-skills --skill deliver-edge-cases -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install product-on-purpose/pm-skills deliver-edge-cases --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/product-on-purpose/pm-skills.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/deliver-edge-cases .claude/skills/deliver-edge-cases && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "deliver-edge-cases" agent skill from https://github.com/product-on-purpose/pm-skills/tree/main/skills/deliver-edge-cases into .claude/skills/deliver-edge-cases/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "deliver-edge-cases", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/product-on-purpose/pm-skills/tree/main/skills/deliver-edge-casesType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add product-on-purpose/pm-skills --skill deliver-edge-cases -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install product-on-purpose/pm-skills deliver-edge-cases --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/product-on-purpose/pm-skills.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/deliver-edge-cases .agents/skills/deliver-edge-cases && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "deliver-edge-cases" agent skill from https://github.com/product-on-purpose/pm-skills/tree/main/skills/deliver-edge-cases into .agents/skills/deliver-edge-cases/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "deliver-edge-cases", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add product-on-purpose/pm-skills --skill deliver-edge-cases -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install product-on-purpose/pm-skills deliver-edge-cases --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/product-on-purpose/pm-skills.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/deliver-edge-cases .cursor/skills/deliver-edge-cases && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "deliver-edge-cases" agent skill from https://github.com/product-on-purpose/pm-skills/tree/main/skills/deliver-edge-cases into .cursor/skills/deliver-edge-cases/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "deliver-edge-cases", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/product-on-purpose/pm-skills.git --path skills/deliver-edge-cases--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add product-on-purpose/pm-skills --skill deliver-edge-cases -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install product-on-purpose/pm-skills deliver-edge-cases --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/product-on-purpose/pm-skills.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/deliver-edge-cases .gemini/skills/deliver-edge-cases && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "deliver-edge-cases" agent skill from https://github.com/product-on-purpose/pm-skills/tree/main/skills/deliver-edge-cases into .gemini/skills/deliver-edge-cases/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "deliver-edge-cases", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install product-on-purpose/pm-skills deliver-edge-casesInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add product-on-purpose/pm-skills --skill deliver-edge-cases -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/product-on-purpose/pm-skills.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/deliver-edge-cases .github/skills/deliver-edge-cases && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "deliver-edge-cases" agent skill from https://github.com/product-on-purpose/pm-skills/tree/main/skills/deliver-edge-cases into .github/skills/deliver-edge-cases/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "deliver-edge-cases", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add product-on-purpose/pm-skills --skill deliver-edge-cases -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install product-on-purpose/pm-skills deliver-edge-cases --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/product-on-purpose/pm-skills.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/deliver-edge-cases .opencode/skills/deliver-edge-cases && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "deliver-edge-cases" agent skill from https://github.com/product-on-purpose/pm-skills/tree/main/skills/deliver-edge-cases into .opencode/skills/deliver-edge-cases/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "deliver-edge-cases", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
deliver-edge-cases- GitHub stars
- 716
- Token cost
- ~1.1k tokens
- SKILL.md length
- 485 words
- Files
- 6 (incl. references)
- Skills in repo
- 68
- Repo updated
- First seen
- Licence
- Apache-2.0
At a glance
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.
- Works in 7 steps: Define the Feature Scope → Walk Through Input Validation → Explore Boundary Conditions → …
- Tasks that involve Async programming
- SKILL.md covers When to Use, When NOT to Use, Instructions and Output Format, plus 2 more sections
- Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
What it does
Deliver Edge Cases is an agent skill 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 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.
Its SKILL.md is about 1.1k tokens, which your agent loads only when the skill is triggered. The skill folder holds 8 other files, including reference files (for example `HISTORY.md`, `evals/output-scenarios/file-upload.md` and `evals/trigger-fixtures.json`).
It sits in Product & Project Management, covering Async programming and User stories. The repository describes itself as: 68 plug-and-play, best-practice product management skills for AI agents: 30 Triple Diamond phase + 11 foundation + 12 utility + 15 tool (Foundation Sprint + Design Sprint). Plus… The licence is Apache-2.0.
When your agent uses it
- Tasks that involve Async programming
- Tasks that involve User stories
Example prompts
- “Use the deliver-edge-cases skill to document edge cases, error states, boundary conditions, race conditions, and recovery paths for a feature - the…”
- “/deliver-edge-cases”
Workflow steps
7 steps, taken from the first numbered list in SKILL.md.
- Define the Feature Scope
- Walk Through Input Validation
- Explore Boundary Conditions
- Map Error States
- Consider Concurrency Issues
- Define Recovery Paths
- Prioritize by Likelihood and Impact
What it can do on your machine
Read from SKILL.md and the folder at commit 1cef1a9. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md.
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
Deliver Edge Cases loads about 1.1k tokens when it runs, and up to ~3.8k if it reads all its reference files. Until then it costs about 129 tokens; SKILL.md has 485 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check passed
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.
SKILL.md
The full file from product-on-purpose/pm-skills at commit 1cef1a9, republished under its Apache-2.0 licence (© product-on-purpose). 485 words, ~1,086 tokens.
Download SKILL.mdSave it as
.claude/skills/deliver-edge-cases/SKILL.md (or your agent's skills folder). This skill also uses 5 other files; get the full folder from GitHub.- name
- deliver-edge-cases
- description
- 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.
- license
- Apache-2.0
- metadata.phase
- deliver
- metadata.version
- 2.1.1
- metadata.updated
- 2026-06-13
- metadata.category
- specification
- metadata.frameworks
- triple-diamond, lean-startup, design-thinking
- metadata.author
- product-on-purpose
<!-- PM-Skills | https://github.com/product-on-purpose/pm-skills | Apache 2.0 -->Edge Cases
An edge cases document systematically catalogs the unusual, boundary, and error scenarios for a feature. While happy-path flows are typically well-specified, edge cases often get discovered in production - causing bugs, poor user experience, and support burden. Documenting edge cases upfront ensures engineering handles them intentionally and QA knows what to test.
When to Use
- When you need to enumerate failure modes, race conditions, timeouts, and boundary or limit scenarios - everything that can go wrong - and define a recovery path for each
- During feature specification before engineering begins
- When preparing QA test plans
- After discovering production bugs to prevent similar issues
- When reviewing PRDs or user stories for completeness
- Before launch to ensure error states have been designed
When NOT to Use
- You need story-scoped Given/When/Then checks for handoff -> use
deliver-acceptance-criteria; this skill catalogs the whole feature's failure surface - The feature is not specified enough to enumerate inputs, states, and limits -> use
deliver-prdfirst - A production incident already happened and you want the learning banked -> use
iterate-lessons-log, then update this catalog with the new case - You need readiness coordination for a launch, not failure analysis -> use
deliver-launch-checklist
Instructions
When asked to document edge cases, follow these steps:
Define the Feature Scope Clearly describe what feature or flow you're analyzing. Edge cases are specific to context - the same input might be valid in one feature and invalid in another.
Walk Through Input Validation Consider every user input: What if it's empty? Too long? Wrong format? Contains special characters? What are the minimum and maximum valid values?
Explore Boundary Conditions Find the edges of acceptable ranges. If a field accepts 1-100, test 0, 1, 100, and 101. Consider pagination boundaries, timeout thresholds, and rate limits.
Map Error States Identify what can go wrong: network failures, permission denied, resource not found, concurrent modifications, expired sessions. Document both the scenario and expected behavior.
Consider Concurrency Issues What if two users act simultaneously? What if the user double-clicks? What if data changes between load and save? Race conditions often cause subtle bugs.
Define Recovery Paths For each error, specify how users recover. What message do they see? Can they retry? Is data preserved? Good error handling turns frustration into confidence.
Prioritize by Likelihood and Impact Not all edge cases need the same attention. High-likelihood + high-impact cases need robust handling; rare + low-impact cases might just need graceful failure.
Show full SKILL.md (85 more words)Show less
Output Format
Use the template in references/TEMPLATE.md to structure the output. A complete edge-case catalog fills every template section: Feature Overview; Edge Case Categories; Error Messages; Recovery Paths; and Test Scenarios.
Quality Checklist
Before finalizing, verify:
- All user inputs have validation edge cases documented
- Boundary conditions are explicitly listed
- Network/system failure scenarios are covered
- Each error state has a defined user-facing message
- Recovery paths are specified (not just error detection)
- Edge cases are prioritized by likelihood and impact
Examples
See references/EXAMPLE.md for a completed example.
© product-on-purpose, Apache-2.0. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
Files
SKILL.md and 5 other files (references) in skills/deliver-edge-cases of product-on-purpose/pm-skills.
- SKILL.md
- HISTORY.md
- evals/output-scenarios/file-upload.md
- evals/trigger-fixtures.json
- references/EXAMPLE.md
- references/TEMPLATE.md
Open the folder on GitHubat commit 1cef1a9
Compare with similar skills
Deliver Edge Cases next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Deliver Edge Cases this skillproduct-on-purpose/pm-skills | 716 | — | ~1.1k | Automated safety check: Pass | Apache-2.0 | |
| User Story Writerdeanpeters/Product-Manager-Skills | 7.2k | 2 repos | ~2.9k | Automated safety check: Pass | Custom licence | |
| Ralph Tui Create Beadssubsy/ralph-tui | 2.5k | 1 repos | ~2.6k | Automated safety check: Pass | MIT | |
| Agile Product Owneralirezarezvani/claude-skills | 28k | 3 repos | ~3.2k | Automated safety check: Pass | MIT | |
| Ralph Tui Create Beads Rustsubsy/ralph-tui | 2.5k | 1 repos | ~2.8k | Automated safety check: Pass | MIT | |
| To Specbestofjs/bestofjs | 3.1k | 21 repos | ~757 | Automated safety check: Pass | MIT |
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Related
Categories
Questions about Deliver Edge Cases
What does Deliver Edge Cases do?
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. Deliver Edge Cases is an agent skill 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 to design for.
When should I use Deliver Edge Cases?
Deliver Edge Cases fits situations like: tasks that involve Async programming; tasks that involve User stories.
How do I install Deliver Edge Cases in Claude Code?
Run `npx skills add product-on-purpose/pm-skills --skill deliver-edge-cases -a claude-code`. Or copy the skill folder (skills/deliver-edge-cases in product-on-purpose/pm-skills) into .claude/skills/deliver-edge-cases in your project. Claude Code loads it when a task matches its description.
How do I install Deliver Edge Cases in Codex?
Run `npx skills add product-on-purpose/pm-skills --skill deliver-edge-cases -a codex`. Or copy the skill folder (skills/deliver-edge-cases in product-on-purpose/pm-skills) into .agents/skills/deliver-edge-cases in your project. Codex loads it when a task matches its description.
Can I use Deliver Edge Cases in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add product-on-purpose/pm-skills --skill deliver-edge-cases -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/deliver-edge-cases, .gemini/skills/deliver-edge-cases, .github/skills/deliver-edge-cases and .opencode/skills/deliver-edge-cases in your project.
What does Deliver Edge Cases need to run?
SKILL.md names no scripts, command-line tools or credentials: Deliver Edge Cases is instructions for the agent only.
Does Deliver Edge Cases access the network?
SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.
Is Deliver Edge Cases safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.
What licence does Deliver Edge Cases use?
Deliver Edge Cases is published under the Apache-2.0 licence (declared in SKILL.md). It allows redistribution, so the full SKILL.md is shown on this page.
How many tokens does Deliver Edge Cases use?
About 1.1k tokens (SKILL.md is roughly 4.3k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 2.7k tokens, read only when the agent opens those files.
What are the alternatives to Deliver Edge Cases?
Skills that share tags, products or a category with Deliver Edge Cases: User Story Writer (deanpeters/Product-Manager-Skills, 7.2k stars), Ralph Tui Create Beads (subsy/ralph-tui, 2.5k stars), Agile Product Owner (alirezarezvani/claude-skills, 28k stars) and Ralph Tui Create Beads Rust (subsy/ralph-tui, 2.5k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Deliver Edge Cases?
product-on-purpose (a GitHub organization) maintains it in product-on-purpose/pm-skills, which has 716 GitHub stars. The repository holds 68 skills in this directory. The repository was last updated on October 8, 2026.
Source: product-on-purpose/pm-skills on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.