Creates detailed, sectionized implementation plans through research, stakeholder interviews, and multi-LLM review. Use when planning features that need thorough pre-implementation analysis.

Gepetto Orchestrates a multi step planning process: Research → Interview → Spec Synthesis → Plan → External Review → Sections CRITICAL: First Actions BEFORE anything else , do these in order: 1. Print Intro Print intro banner immediately: 2. Validate Spec File Input Check if user provided @file at invocation AND it's a spec file (ends with .md ). If NO @file was provided OR the path doesn't end with .md , output this and STOP: Do not continue. Wait for user to re invoke with a .md file path. 3. Setup Planning Session Determine session state by checking existing files: 1. Set planning dir = parent directory of the spec file 2. Set initial file = the spec file path 3. Scan for existing planning files: claude research.md claude interview.md claude spec.md claude plan.md claude integration notes.md claude ralph loop prompt.md claude ralphy prd.md reviews/ directory sections/ directory 4. Determine mode and resume point: Files Found Mode Resume From None new Step 4 research only resume Step 6 (interview) research + interview resume Step 8 (spec synthesis) + spec resume Step 9 (plan) + plan resume Step 10 (external review) + reviews resume Step 11 (integrate) + integration notes resume Step 12 (user review) + sections/index.md resume Step 14 (write sections) all sections complete resume Step 15 (execution files) + claude ralph loop prompt.md + claude ralphy prd.md complete Done 5. Create TODO list with TodoWrite based on current state Print status: If resuming: Logging Format Workflow 4. Research Decision See [research protocol.md](references/research protocol.md). 1. Read the spec file 2. Extract potential research topics (technologies, patterns, integrations) 3. Ask user about codebase research needs 4. Ask user about web research needs (present derived topics as multi select) 5. Record which research types to perform in step 5 5. Execute Research See [research protocol.md](references/research protocol.md). Based on decisions from step 4, launch research subagents: Codebase research: Task(subagent type=Explore) Web research: Task(subagent type=Explore) with WebSearch If both are needed, launch both Task tools in parallel (single message with multiple tool calls). Important: Subagents return their findings they do NOT write files directly. After collecting results from all subagents, combine them and write to <planning dir /claude research.md . Skip this step entirely if user chose no research in step 4. 6. Detailed Interview See [interview protocol.md](references/interview protocol.md) Run in main context (AskUserQuestion requires it). The interview should be informed by: The initial spec Research findings (if any) 7. Save Interview Transcript Write Q&A to <planning dir /claude interview.md 8. Write Initial Spec (Spec Synthesis) Combine into <planning dir /claude spec.md : Initial input (the spec file) Research findings (if step 5 was done) Interview answers (from step 6) This synthesizes the user's raw requirements into a complete specification. 9. Generate Implementation Plan Create detailed plan → <planning dir /claude plan.md IMPORTANT : Write for an unfamiliar reader. The plan must be fully self contained an engineer or LLM with no prior context should understand what we're building, why , and how just from reading this document. 10. External Review See [external review.md](references/external review.md) Launch TWO subagents in parallel to review the plan: 1. Gemini via Bash 2. Codex via Bash Both receive the plan content and return their analysis. Write results to <planning dir /reviews/ . 11. Integrate External Feedback Analyze the suggestions in <planning dir /reviews/ . You are the authority on what to integrate or not. It's OK if you decide to not integrate anything. Step 1: Write <planning dir /claude integration notes.md documenting: What suggestions you're integrating and why What suggestions you're NOT integrating and why Step 2: Update <planning dir /claude plan.md with the integrated changes. 12. User Review of Integrated Plan Use AskUserQuestion: Options: "Done reviewing" Wait for user confirmation before proceeding. 13. Create Section Index See [section index.md](references/section index.md) Read claude plan.md . Identify natural section boundaries and create <planning dir /sections/index.md . CRITICAL: index.md MUST start with a SECTION MANIFEST block. See the reference for format requirements. Write index.md before proceeding to section file creation. 14. Write Section Files — Parallel Subagents See [section splitting.md](references/section splitting.md) Launch parallel subagents one Task per section for maximum efficiency: 1. First, parse sections/index.md to get the SECTION MANIFEST list 2. Then launch ALL section Tasks in a single message (parallel execution): Wait for ALL subagents to complete before proceeding. 15. Generate Execution Files — Subagent Delegate to subagent to reduce main context token usage: Wait for subagent completion before proceeding. 16. Final Status Verify all files were created successfully: All section files from SECTION MANIFEST claude ralph loop prompt.md claude ralphy prd.md 17. Output Summary Print generated files and next steps:

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