sw-use-case-creator

name	sw-use-case-creator
description	Use when user wants to create use cases, detailed system behavior specs, actor flows, or a use case document from user-stories.md, vision.md, or any software description – generates requirements/use-cases.md silently.
version	1.2.0
author	Lehnert

SW Use Case Creator

Overview

Reads requirements/user-stories.md (from sw-user-story-creator) or falls back to requirements/vision.md and produces a complete, professional use case document at requirements/use-cases.md. Operates silently – no file content is shown in the chat.

Language detection: Read the user's input language and respond entirely in that language. Default to German if undetectable.

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Required Input – Check in Order

1. requirements/user-stories.md exists → primary source. Extract epics, roles, goals, and acceptance criteria.

2. requirements/user-stories.md missing, requirements/vision.md exists → use vision.md to derive use cases from features and target audience.

3. Both missing, user provided description → use the description as input.

4. All missing, no input given → stop and respond:

   Neither requirements/user-stories.md nor requirements/vision.md found. Run /sw-user-story-creator or /sw-idea-analyzer first, or provide your description directly: /sw-use-case-creator <your description>

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Use Case Format

Every use case follows this exact structure:

## UC-XXX: <Use Case Name>

**Actors:** <Primary Actor>, <Secondary Actor (if any)>
**Preconditions:** <What must be true before this use case can start>
**Postconditions:** <What is true after successful completion>

### Main Flow
1. Step one
2. Step two
3. ...

### Alternative Flows
- **A1 – <Name>:** <Trigger condition> → <Steps>
- **A2 – <Name>:** <Trigger condition> → <Steps>

### Exceptions
- **E1 – <Name>:** <Error condition> → <System response>

### Acceptance Criteria
- [ ] Linked to US-XXX: <criterion>
- [ ] Linked to US-XXX: <criterion>

Rules:

• One use case per significant user goal (not per button or field)
• Actors = specific roles from target audience, never "the system" as primary actor
• Main flow = happy path only, numbered steps
• Alternative flows = valid but non-default paths
• Exceptions = error states the system must handle
• Acceptance criteria = link back to user story IDs where possible
• IDs start at UC-001 and increment sequentially across the entire document
• If requirements/use-cases.md already exists: read the entire file, find the highest UC-XXX ID, continue from the next number, and append new use cases to the end — never modify existing content

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Deriving Use Cases from Input

Source	How to derive use cases
user-stories.md	One use case per epic or major workflow; group 2–4 related stories into one UC
vision.md	One use case per core MVP feature
Free text	Identify actor + goal pairs; each pair = one use case

Aim for 5–10 use cases for a typical MVP. Do not create a use case for every micro-interaction — CRUD is one UC, not four.

When to merge stories into one UC:

• Related stories share the same actor and workflow (e.g., "view profile" + "edit profile" → UC "Manage Profile")
• The stories form a single coherent interaction sequence

When to keep them separate:

• Different primary actors
• Completely independent workflows that don't share preconditions or main flow steps

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Output Rules

• Never output the file content in the chat. All content goes to the file only.
• Do not show any use case text, flows, or Markdown in the chat response.
• The only chat output allowed is the confirmation lines at the end.
• Use the user's language throughout the file content.
• Never truncate – include every flow, every exception.

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File Output

After generating all use cases, write to requirements/use-cases.md in the repository root.

Steps:

1. If requirements/ does not exist: mkdir -p requirements
2. Write the complete document to requirements/use-cases.md
3. Print only these lines to the chat – nothing else:

✅ File created: requirements/use-cases.md Open it in your editor or commit it.

One optional summary sentence max (e.g. "Generated 7 use cases covering all MVP features."). No code blocks, no Markdown content, no full output.

requirements/use-cases.md structure:

# Use Cases: <Project Title>

> Generated: <YYYY-MM-DD>
> Source: requirements/user-stories.md

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## UC-001: <Use Case Name>

**Actors:** ...
**Preconditions:** ...
**Postconditions:** ...

### Main Flow
1. ...

### Alternative Flows
- **A1 – ...:** ...

### Exceptions
- **E1 – ...:** ...

### Acceptance Criteria
- [ ] ...

---

## UC-002: <Use Case Name>
...

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Next Skill

▶ Next steps:

• Run /sw-tech-stack-planner to select the tech stack and generate requirements/tech-stack.yaml
• Run /sw-diagram-creator to generate sequence or flowchart diagrams from your use cases