Prep For

You are helping Jim prepare to work on a backlog item in isolation.

Usage:

• /prep-for <issue-id> (e.g., /prep-for b3, /prep-for B18) - Single worktree
• /prep-for <issue-id> <variants> (e.g., /prep-for b7 3) - Multiple variant worktrees

Step 1: Parse Arguments

Extract the issue identifier and optional variant count from the command:

• b3, B3, 3 → normalize to B3
• Case insensitive, optional B prefix
• Optional second argument: number of variants (1-5)
  • If omitted: create single worktree (no variant suffix)
  • If provided: create N worktrees with -1, -2, etc. suffixes

Validation:

• Variants must be 1-5 (prevent resource exhaustion)
• If variants > 1, warn about disk usage (each variant = 2 databases + data copies)

Step 2: Locate Backlog Item

Search for the backlog item file in docs/backlog/:

• Pattern: B<number>-*.md (e.g., B3-download-state-machine.md)
• Read the file to extract:
  • Full title (from # B3: Title line)
  • Status
  • Priority
  • Any warnings (e.g., "DESIGN WORK REQUIRED")

If not found, error: "Issue B not found in docs/backlog/"

Step 3: Collect Baseline Metrics (Once)

IMPORTANT: Collect baseline from main repo BEFORE creating worktrees.

Run tests in current directory to establish baseline:

pytest -q 2>&1

Extract from output:

• Passed count
• Skipped count
• Failed count (should be 0)
• Total test count

If tests fail, include warning in all prompts about starting from non-green baseline.

Step 4: Setup Worktree(s)

Look for project-specific worktree setup instructions:

1. Check CLAUDE.md for worktree setup instructions
2. Check README.md for worktree setup instructions
3. Otherwise, use default approach

Derive slug from backlog filename:

• B3-download-state-machine.md → b3-download-state-machine

Naming patterns:

Single worktree (no variant count specified):

• Worktree path: .worktrees/b<number>-<slug>
• Branch name: feature/b<number>-<slug>
• Example: .worktrees/b7-media-group-support with branch feature/b7-media-group-support

Multiple variants (variant count specified):

• Worktree path: .worktrees/b<number>-<slug>-<N>
• Branch name: feature/b<number>-<slug>-<N>
• Example with 3 variants:
  • .worktrees/b7-media-group-support-1 with branch feature/b7-media-group-support-1
  • .worktrees/b7-media-group-support-2 with branch feature/b7-media-group-support-2
  • .worktrees/b7-media-group-support-3 with branch feature/b7-media-group-support-3

Default approach (if no project-specific instructions):

# Single worktree
git worktree add .worktrees/b<number>-<slug> -b feature/b<number>-<slug>

# Multiple variants (loop)
git worktree add .worktrees/b<number>-<slug>-<N> -b feature/b<number>-<slug>-<N>

Project-specific approach:

• Call project's setup script with appropriate path/branch name
• Example: ./scripts/setup-worktree.sh feature/b7-media-group-support-1 .worktrees/b7-media-group-support-1

After worktree creation:

• Record all worktree paths for summary

Step 5: Generate Autonomous Execution Prompts

Generate one prompt per worktree created.

For single worktree:

---

I'm in the `<worktree-name>` worktree to implement **B<number>: <title>**.

Use the `autonomous-execution` skill to implement this backlog item.

**Backlog item:** `./docs/backlog/<backlog-filename>`

This is a single backlog item (not a full implementation plan), so follow the **Backlog Item Workflow** from the `autonomous-execution` skill.

**Current baseline:** <passed> passed, <skipped> skipped, <failed> failed (total: <total> tests).

<if any warnings from backlog item, add:>
**Special considerations:**
<warnings here>

**Time budget:** <suggest based on priority/complexity>

Work autonomously to completion in this worktree.

---

For multiple variants:

---

I'm in the `<worktree-name>` worktree to implement **B<number>: <title>**.

**This is variant <N> of <M>.**

Use the `autonomous-execution` skill to implement this backlog item.

**Backlog item:** `./docs/backlog/<backlog-filename>`

This is a single backlog item (not a full implementation plan), so follow the **Backlog Item Workflow** from the `autonomous-execution` skill.

**Current baseline:** <passed> passed, <skipped> skipped, <failed> failed (total: <total> tests).

<if any warnings from backlog item, add:>
**Special considerations:**
<warnings here>

**Time budget:** <suggest based on priority/complexity>

Work autonomously to completion in this worktree.

---

Time budget suggestions:

• Low priority, simple refactor: 1-2 hours
• Medium priority, feature work: 2-4 hours
• High priority or "DESIGN WORK REQUIRED": 4-6 hours

Step 6: Summary Output

For single worktree:

✓ Worktree setup complete: <worktree-path>
✓ Baseline recorded: <test-summary>

Copy the prompt below into a new Claude Code session in this worktree:

Then display the generated prompt in a code block.

For multiple variants:

✓ Created <M> variant worktrees for B<number>:
  - <worktree-path-1>
  - <worktree-path-2>
  - ...
✓ Baseline recorded: <test-summary>

⚠️  Resource usage: ~<estimate> GB disk space (<M> variants × 2 databases each)

Cleanup when done:
  # Drop databases
  <list psql DROP DATABASE commands for all variants>

  # Remove worktrees
  <list git worktree remove commands for all variants>

---

Copy each prompt below into a separate Claude Code session in the corresponding worktree:

Then display all generated prompts, one per variant, separated clearly with headers like:

### Variant 1: <worktree-path-1>

<prompt-1>

### Variant 2: <worktree-path-2>

<prompt-2>

...

Error Handling

If backlog item not found:

• List available backlog items
• Suggest correct issue ID

If variant count invalid:

• Error: "Variant count must be 1-5. Requested: "
• Explanation: "Each variant requires 2 databases + data copies. Use lower count to avoid resource exhaustion."

If any worktree already exists:

• Error: "Worktree already exists at . Remove it first or use a different issue."
• For variants: Check ALL variant paths before creating any
• Don't create partial sets - either all succeed or none

If tests fail in baseline:

• Include warning in all prompts: "⚠️ Starting from non-green baseline. Fix existing failures before implementing B."

If not in a git repo:

• Error: "Not in a git repository. Run this command from a project root."

Notes

• This command works across any project with a docs/backlog/ directory
• Project-specific setup (databases, config) is handled per project's CLAUDE.md or README.md
• The generated prompts are optimized for autonomous-execution skill usage
• Baseline metrics help verify no regressions during autonomous work
• No files are written - prompts are displayed for copy/paste only
• Variants are completely isolated - separate worktrees, branches, and databases
• Jim will provide specific approach guidance to each variant as needed