map-systems

When this skill is invoked:

1. Parse Arguments

Two modes:

• No argument: /map-systems — Run the full decomposition workflow (Phases 1-5) to create or update the systems index.
• next: /map-systems next — Pick the highest-priority undesigned system from the index and hand off to /design-system (Phase 6).

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2. Phase 1: Read Concept (Required Context)

Read the product concept and any existing design work. This provides the raw material for systems decomposition.

Required:

• Read design/docs/product-concept.md — fail with a clear message if missing:

  "No product concept found at design/docs/product-concept.md. Run /brainstorm first to create one, then come back to decompose it into systems."

Optional (read if they exist):

• Read design/docs/product-pillars.md — pillars constrain priority and scope
• Read design/docs/systems-index.md — if exists, resume from where it left off (update, don't recreate from scratch)
• Glob design/docs/*.md — check which system PRDs already exist

If the systems index already exists:

• Read it and present current status to the user
• Use AskUserQuestion to ask: "The systems index already exists with [N] systems ([M] designed, [K] not started). What would you like to do?"
  • Options: "Update the index with new systems", "Design the next undesigned system", "Review and revise priorities"

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3. Phase 2: Systems Enumeration (Collaborative)

Extract and identify all systems the product needs. This is the creative core of the skill — it requires human judgment because concept docs rarely enumerate every system explicitly.

Step 2a: Extract Explicit Systems

Scan the product concept for directly mentioned systems and mechanics:

• Core Mechanics section (most explicit)
• Core Loop section (implies what systems drive each loop tier)
• Technical Considerations section (networking, procedural generation, etc.)
• MVP Definition section (required features = required systems)