Scenario

scenario

> Decompose a feature across 12 risk dimensions → exhaustive, severity-tagged edge cases.

What this is — and isn't

| Skill | Does | |---|---| | vd:test | Runs tests, reports pass/fail | | vd:brainstorm | Explores solution options | | scenario | Enumerates edge cases & failure modes to test — does not run or fix them |

Output is an input to test-writing / QA / vd:plan risk sections — not executable tests.

Modes

| Mode | Behaviour | |---|---| | (default) | One pass over all 12 dimensions → scenario list. | | --saturation | Iterative rounds until coverage is exhausted (2 consecutive zero-new rounds) or --iterations cap (default 5). |

--iterations only applies with --saturation (default mode is a single pass).

Workflow

1. Read the target — the file/function or feature description. Identify inputs, outputs, state, external calls.
2. Walk the 12 dimensions — see [references/dimensions.md](references/dimensions.md). For each, ask "what input/condition in this category breaks the target?"
3. Emit scenarios — group by dimension; each: a one-line condition, severity (Critical/High/Med/Low), why it breaks, suggested test/assertion.
4. (saturation) — repeat with a completeness critic ("which dimension or angle is still thin?"); dedupe against the seen-set; stop per the rules in [references/saturation-loop.md](references/saturation-loop.md).
5. Save the report — write to the injected Reports: path. Filename: scenario-{date}-{slug}.md.

Final handoff must include an openable report location, such as [scenario-report.md](/absolute/path/to/scenario-report.md) or file:///absolute/path/to/scenario-report.md, not just the basename.

Output shape

## 
- **[High]**  — breaks because . Test: .
- **[Low]**   — ...

End with a coverage line: Dimensions covered: 12/12 · scenarios: N · saturation rounds: R.

Limitations (honest)

• Enumeration quality depends on understanding the target — read it, don't guess.
• Not a fuzzer or property tester — it proposes cases, it doesn't execute them.
• --saturation is bounded — it will stop at the iteration cap even if more cases theoretically exist (logs that it stopped).

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: vanducng
• Source: vanducng/skills
• License: MIT
• Homepage: https://skills.vanducng.dev

Install and usage instructions live in the source repository linked above.