implement-github-feature

name	implement-github-feature
description	Design and implement a new feature or component from a GitHub issue. Use for net-new functionality, not bug fixes.
disable-model-invocation	true
allowed-tools	Read, Grep, Glob, Edit, Write, Bash(gh issue view *), Bash(gh pr view *), Bash(git status), Bash(git diff *), Bash(git log *), Bash(git branch *), Bash(git checkout *), Bash(git add *), Bash(git commit *), Bash(npm run build), Bash(npm run lint), Bash(ls *)

Usage: /implement-github-feature ISSUE_NUMBER

Example: /implement-github-feature 281

Implement GitHub feature request $ARGUMENTS following AgnosticUI conventions, accessibility standards, and CSS-first principles.

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Setup

1. Read project context
   • Read .claude/PROJECT_CONTEXT.md
   • Understand:
     • Repository structure
     • Design principles
     • Accessibility requirements
     • Branch conventions
     • Component workflows

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Phase 0: Safety Checks (Required)

2. Verify clean starting state
   • Run git status
   • Confirm:
     • Working directory is clean
     • Current branch is master
   • If either condition fails:
     • STOP
     • Ask the user to resolve before continuing

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Phase 1: Branching

3. Propose feature branch
   • Follow convention: issue-$ARGUMENTS/short-descriptive-name
   • Example: issue-281/selection-card-group
   • Run:

     git checkout -b issue-$ARGUMENTS/short-description
     

   • WAIT FOR USER APPROVAL of branch name before proceeding

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Phase 2: Issue Analysis & Intent Extraction (No Code)

4. Analyze the GitHub issue

   • Fetch full details:

     gh issue view $ARGUMENTS
     

   • Extract and summarize:
     • Feature goals
     • Non-goals / constraints
     • API expectations
     • Accessibility requirements
     • Styling and theming expectations
     • Framework implications (Lit / React / Vue)

5. Study existing related components

   • Identify components this feature will compose or resemble
   • Read their implementations in v2/lib/src/components/
   • Note patterns for:
     • Props and attributes
     • Slot usage
     • CSS custom properties
     • ::part exposure
     • Event dispatching
     • Accessibility implementation
   • This ensures consistency with established AgnosticUI conventions

6. Confirm feature classification

   • This is a:
     • Net-new component OR
     • Major enhancement (not a bug fix)
   • If scope appears ambiguous:
     • Ask the user before proceeding

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Phase 3: Design Proposal (Hard Stop Before Code)

8. Propose high-level design

   • Identify:
     • New components to be created
     • Public vs internal APIs
     • Required props vs optional props
     • Slot usage and responsibilities
     • Accessibility model (labels, roles, keyboard behavior)
     • Shadow DOM strategy (::part, ::slotted)
   • Explicitly call out:
     • Web Component constraints
     • CSS-first decisions
     • What is intentionally not supported

9. Propose file & directory layout

   • Core components:
     • v2/lib/src/components/...
   • Documentation:
     • v2/site/docs/components/...
   • Storybook playgrounds:
     • Lit
     • React
     • Vue
   • Examples:
     • Lit / React / Vue test examples

10. WAIT FOR USER APPROVAL

• Do not create files
• Do not write code
• Proceed only after explicit approval of:
  • API shape
  • Accessibility approach
  • Styling strategy

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Phase 4: Scaffolding (Minimal, Intentional)

11. Create initial scaffolding

    • Create component directories
    • Add placeholder files where appropriate
    • Add minimal README or doc stubs if needed
    • No implementation logic yet

12. Show scaffolding diff

    • Use git diff
    • Explain what was created and why
    • WAIT FOR USER APPROVAL

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Phase 5: Core Implementation (Lit Web Components First)

13. Implement core component(s)

    • Work only in:
      • v2/lib/src/components/
    • Follow:
      • CSS-first approach
      • Design token usage
      • Accessibility requirements
    • Ensure:
      • Keyboard interaction works
      • Labels and semantics are correct
      • Shadow DOM parts are intentional and minimal

14. Verify build

    • Run npm run build in v2/lib/
    • Fix any compilation errors
    • Run npm run lint if available

15. Pause for review

    • Explain:
      • DOM structure
      • Slot behavior
      • ::part surface
      • Accessibility decisions
    • WAIT FOR USER APPROVAL before proceeding

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Phase 6: Framework Integrations

16. Integrate with frameworks

    • React playground
    • Vue playground
    • Lit playground
    • APIs should feel idiomatic but map 1:1 conceptually

17. Add Storybook stories

    • Demonstrate:
      • Core use cases
      • Variants
      • Accessibility states
    • Ensure consistency across frameworks

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Phase 7: Documentation & Examples

18. Write documentation

    • Add VitePress docs:
      • API
      • Slots vs props
      • Styling guidance
      • Accessibility notes
    • Update or add playbooks if applicable

19. Update examples

    • Verify examples compile and behave correctly
    • Keep examples minimal and educational

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Phase 8: Final Review & Commit

20. Final verification

    • Review:
      • git diff
      • Accessibility behavior
      • Styling hooks
      • API consistency
    • Ensure no accidental breaking changes

21. Prepare commit

    • Stage changes:

      git add .
      

    • Commit message format:

      Add #$ARGUMENTS: [concise feature description]
      

    • Show commit contents
    • WAIT FOR USER APPROVAL before committing

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Phase 9: Handoff

22. Explain next steps
    • User is on branch: issue-$ARGUMENTS/...
    • Review with:

      git diff master
      

    • Push when ready:

      git push -u origin issue-$ARGUMENTS/...
      

    • Create PR:

      gh pr create --base master --head issue-$ARGUMENTS/...
      

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Important Rules

• NEVER work directly on master
• NEVER push without explicit user permission
• ALWAYS stop at design gates
• ALWAYS prioritize accessibility over convenience
• Prefer slots for layout, props for semantics
• CSS custom properties > ::part > ::slotted
• Do not assume intent — if unclear, ask

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