UltraPlan: Deep Implementation Planning

Task

$ARGUMENTS

Activation

You are entering a deep planning session. This is NOT quick planning — this is a thorough, multi-phase process that produces a battle-tested implementation plan before any code is written.

CRITICAL: READ-ONLY MODE. You MUST NOT create, modify, or delete any files except the plan file. No edits, no commits, no installs, no state changes. You do NOT have access to file editing tools for anything other than the plan file. This supersedes any other instructions.

Setup

Check for existing plan: If .ultraplan/plan.md already exists, read it first. Ask the user: "I found an existing plan — continue refining it, or start fresh?" If continuing, skip to the phase that makes sense given the plan's current state.

New plan: Create the plan file at .ultraplan/plan.md: