name: carve version: 1.1.0 description: Turn a PRD into a multi-phase implementation plan using tracer-bullet vertical slices, saved as a local Markdown file in ./plans/. Use when user wants to break down a PRD, create an implementation plan, plan phases from a PRD, or mentions "tracer bullets".

Carve — PRD to Plan

Break a PRD into a phased implementation plan using vertical slices (tracer bullets). Output is a Markdown file in ./plans/.

CLI tools — special case. If the PRD describes a command-line tool, suggest running /agent-cli in design mode before slicing. Locking flags, output formats, and error model up front prevents rework once vertical slices start landing.

Process

1. Confirm the PRD is in context

If it isn't, ask the user to paste it or point you to the file.

2. Identify durable architectural decisions

Reasoning approach: Mentally trace 2-3 likely implementation paths through the PRD end-to-end. A "durable" decision is one all paths share. Reason through alternatives before listing — surface hidden assumptions, then prune.

Before slicing, identify high-level decisions that are unlikely to change throughout implementation:

• System architecture style
• Data model shape and key entities
• Authentication / authorization approach
• Third-party service boundaries
• Key constraints (compliance, performance, budget)

These go in the plan header so every phase can reference them.

3. Draft vertical slices

Reasoning approach: Hold the full PRD in mind while slicing; verify each slice mentally before writing.

Break the PRD into tracer bullet phases. Each phase is a thin vertical slice that cuts through ALL integration layers end-to-end, NOT a horizontal slice of one layer:

• Each slice delivers a narrow but COMPLETE path from user-facing behavior through to data persistence
• A completed slice is demoable or verifiable on its own
• Prefer many thin slices over few thick ones
• Do NOT include specific file names, function names, or implementation details that are likely to change as later phases are built
• DO include durable decisions: architecture style, data model shapes, entity names

Push back on slice creep. Every slice must trace to an explicit user story in the PRD. If a draft slice includes functionality not in the PRD ("while we're in there, let's also add X"), cut X — propose it as a follow-up phase or send it back to /blueprint. Phases that drift past the PRD turn /tdd into an open-ended design exercise.

Acceptance criteria must be verifiable. Every AC must reduce to an automated test, an observable artifact, or a runnable command — the plan template shows the annotation format. "It works" or "feature complete" do not qualify; sharpen before the phase ships to /dispatch or /tdd.

4. Quiz the user

Present the proposed breakdown as a numbered list showing each phase's title and the user stories from the PRD it covers. Ask whether the granularity feels right (too coarse / too fine) and whether any phases should be merged or split. Iterate until the user approves the breakdown.

5. Write the plan file

Create ./plans/ if it doesn't exist. Write the plan as a Markdown file named after the feature (e.g. ./plans/user-onboarding.md). Use the template in plan-template.md.