app-implement

app-implement Implement app changes based on APP_BRIEF.md. Compares against last execution, implements delta. --dry-run (optional): Print planned changes without executing /app-implement /app-implement --dry-run

Pre-flight Check

Before proceeding, verify you are in a scaffolded Cribl app folder. If you are not, stop and tell the user: "You must run this skill from within a scaffolded Cribl app folder."

Instructions

You are implementing a Cribl app based on an APP_BRIEF.md file. Use Capra UI by default for all components. Before starting, review ./references/cribl-apps-guidance.md to avoid common pitfalls with KV store, state management, error handling, and other Cribl-specific patterns.

Follow this workflow:

1. Validate Prerequisites

• Check that APP_BRIEF.md exists in the working directory
• If missing, error with: "APP_BRIEF.md not found. Run /app-brief first."
• Create /executions directory if it doesn't exist

2. Load & Compare Versions

• Read the current APP_BRIEF.md
• Find the most recent APP_BRIEF_*.md in /executions (sort by timestamp in filename)
• If no prior execution: treat entire current brief as new work (delta = all of it)
• If prior execution exists: diff the two to identify:
  • New sections/requirements
  • Modified sections/requirements
  • Sections removed (note: don't undo these)

3. Parse Delta into Action Items

• Extract specific implementation tasks from the delta
• For each task, create one clear, actionable line describing what will be done
• Example lines:
  • "Create new component: UserInput"
  • "Update API endpoint /search to support filtering"
  • "Add test coverage for AuthService"

4. Dry-Run Mode (if --dry-run flag provided)

• Print header: "=== DRY RUN: Planned Changes ==="
• Print each action item as one line (no descriptions, just the action)
• Print footer: "=== End Dry Run ==="
• Example output:

  === DRY RUN: Planned Changes ===
  Create new component: UserInput
  Update API endpoint /search to support filtering
  Add test coverage for AuthService
  === End Dry Run ===
  

5. Implementation Mode (normal execution, no --dry-run)

• Execute the delta: create files, modify code, update configs as needed
• Read the app id from APP_DEFINITION.md (under "## App ID" section)
• Update the "name" field in package.json to match the app id
• Remove all linter errors, run npm run lint

6. Archive This Run

• Copy current APP_BRIEF.md to /executions/APP_BRIEF_[ISO8601-timestamp].md
• Use format: APP_BRIEF_2026-07-31T14-30-45Z.md (ISO 8601, with colons replaced by hyphens for filesystem compatibility)
• This becomes the baseline for the next run

7. Confirm Package.json Update

• Verify that package.json's "name" field now matches the app id from APP_DEFINITION.md

Key Principles

• Source of truth: Current APP_BRIEF.md always wins
• Idempotency: Skill can run repeatedly; each run only touches what changed
• Stateless between runs: /executions folder is the only state persistence