start-issue

name	start-issue
description	Load a GitHub Issue, create a branch, and develop an implementation plan.

/start-issue

Load a GitHub Issue, create a branch, and develop an implementation plan.

Usage

/start-issue <issue-number> [--force] [--current-branch]

Arguments

Argument	Type	Required	Description
issue-number	integer	Yes	GitHub Issue number
--force	flag	No	Skip plan mode and all interactive confirmations (including TDD user approval). Full autonomous mode: Do not output any questions or confirmations as text. Execute all steps (including Issue reporting) without pausing.
--current-branch	flag	No	Skip branch creation, use the current branch

Instructions

When the user invokes /start-issue <number>, follow these steps:

Step 1: Load Issue

gh issue view <number> --json number,title,body,labels,state

Verify the issue exists and is open. If not open, warn the user.

Step 2: Determine Branch Type

If --current-branch is specified, skip this step entirely.

Based on the issue labels and content, determine the appropriate branch prefix:

Label	Prefix
enhancement, feature	feat/
bug	fix/
refactoring, refactor	refactor/
documentation, docs	docs/
test	test/
chore	chore/

If no matching label, check title/body for keywords. Default to feat/.

Step 3: Create Branch

If --current-branch is specified, skip branch creation. Instead, display the current branch name:

git branch --show-current

If the result is empty (detached HEAD), display an error and abort.

Otherwise (default behavior):

Generate branch name: <prefix>/<issue-number>-<normalized-title>

Normalization rules:

• Lowercase
• Remove special characters
• Replace spaces with hyphens
• Limit to 40 characters

git checkout -b <branch-name>

If branch exists, checkout instead of create.

Step 4: Plan Implementation

Unless --force is specified, enter plan mode before proceeding. With --force, execute all phases directly without entering plan mode and without any interactive confirmations.

CRITICAL (--force mode): You are running in a non-interactive claude -p pipeline. There is no user to respond. You MUST NOT output any questions, confirmations, or prompts as text (e.g., "〜しますか？", "〜してよろしいですか？"). Execute every step autonomously and proceed to the next step immediately. This applies to ALL steps including Step 5 (Report to Issue).

Regardless of --force, execute the following phases to create an implementation plan.

First, read the workflow configuration:

cat .claude/workflow-config.json

Check documentation.ddd.enabled to determine if DDD workflow is active.

Phase 1: Analyze Requirements

1. Extract requirements from issue body
2. Identify acceptance criteria
3. If --force is not specified, clarify any ambiguous requirements with user. With --force, make reasonable assumptions and proceed.

Phase 2: Identify Impact Scope

1. Identify affected code files
2. Identify affected documentation using doc-updater skill detection patterns:

Change Type	Documentation Impact
New CLI option	README, --help output
API endpoint added/changed	API documentation
Configuration option added	Config guide
Environment variable added	Setup guide
Feature added	Feature documentation

Target documents are defined in documentation.paths from workflow config.

Phase 3: Document-Driven Development (DDD)

Skip this phase if documentation.ddd.enabled is false.

Before implementation, update documentation as specification using doc-updater skill:

1. Draft documentation changes

   • Write usage examples for new features
   • Document expected behavior
   • Define configuration options
   • If documentation.ddd.retcon_writing is true, write documentation as if the feature already exists
     • Purpose: Produces clearer, more confident documentation
     • Example: "Run --format json" instead of "will allow users to..."

2. Update target documents (from documentation.paths):

   • README.md - Usage and examples
   • docs/ - Detailed documentation
   • CLI --help text (in code comments)
   • CHANGELOG.md (from documentation.changelog) if applicable

3. Review documentation with user (skip if --force — treat documentation as approved and proceed)

   • Documentation becomes the "contract" for implementation

Phase 4: Design Test Cases (TDD Approach)

Based on the documented specification, design test cases using tdd-workflow skill:

1. Identify test scenarios from documentation
2. Define expected inputs and outputs
3. Consider edge cases documented in Phase 3

If --force is specified:

Skip all TDD user confirmation steps and execute the Red-Green-Refactor cycle autonomously without user approval:

• Do not ask "Do you want me to follow TDD workflow?" — assume yes
• Do not wait for user approval of test cases — proceed directly to Red confirmation
• Do not output any question or confirmation text (e.g., "〜しますか？") — there is no user to respond
• Write tests → confirm failure (Red) → implement (Green) → refactor — all automatically
• Still report test results at each phase, but do not pause for confirmation

If --force is not specified (default):

Follow the standard TDD workflow with user confirmation:

• Ask the user if they want to follow TDD workflow
• Present test cases and get user approval before proceeding
• Wait for user confirmation at each TDD phase transition

Phase 5: Create Implementation Plan

1. List tasks in dependency order
2. Identify potential risks and mitigations
3. Summarize in table format

Step 5: Report to Issue

With --force: Execute this step immediately without asking for confirmation. Do not output questions like "Issueに報告しますか？" — just do it.

Post the plan as a comment on the issue using issue-reporter skill:

## Implementation Plan

**Task**: [Issue title]

### Plan
1. [Step 1]
2. [Step 2]
...

### Expected Challenges
- [Challenge 1]

---
*Posted by Claude Code at YYYY-MM-DD HH:MM*

Output Format

## Issue #<number>: <title>

### Requirements
[Requirements extracted from issue body]

### Documentation Updates (DDD)
- [ ] [Target document]: [Update description]
- [ ] [Target document]: [Update description]

### Test Plan
- [Test case 1]
- [Test case 2]

### Implementation Plan
1. [Step 1]
2. [Step 2]
...

### Verification
[Verification steps]

Error Handling

Error	Action
Issue not found	Display error with gh issue view suggestion
Issue is closed	Warn user and ask for confirmation. With --force, warn in output but proceed without confirmation.
gh not authenticated	Display gh auth login instruction
Uncommitted changes	Ask user to commit or stash changes
Branch creation failed	Display error details
Detached HEAD with --current-branch	Display error: not on a branch, checkout a branch first
workflow-config.json not found	Display error: "Run /init to create configuration."
documentation section missing	Treat as DDD disabled, inform user
documentation.paths missing or empty	Display warning about no documentation targets
doc-updater/tdd-workflow skill not found	Display error with skill installation guidance