Decompose a game concept into individual systems, map dependencies, prioritize design order, and create the systems index.

When this skill is invoked: 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). Also resolve the review mode (once, store for all gate spawns this run): 1. If review [full lean solo] was passed → use that 2. Else read production/review mode.txt → use that value 3. Else → default to lean See .claude/docs/director gates.md for the full check pattern. Phase 1: Read Concept (Required Context) Read the game concept and any existing design work. This provides the raw material for systems decomposition. Required: Read design/gdd/game concept.md — fail with a clear message if missing : "No game concept found at design/gdd/game concept.md . Run /brainstorm first to create one, then come back to decompose it into systems." Optional (read if they exist): Read design/gdd/game pillars.md — pillars constrain priority and scope Read design/gdd/systems index.md — if exists, resume from where it left off (update, don't recreate from scratch) Glob design/gdd/ .md — check which system GDDs 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" Phase 2: Systems Enumeration (Collaborative) Extract and identify all systems the game 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 game 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) Step 2b: Identify Implicit Systems For each explicit system, identify the hidden systems it implies. Games always need more systems than the concept doc mentions. Use this inference pattern: "Inventory" implies: item database, equipment slots, weight/capacity rules, inventory UI, item serialization for save/load "Combat" implies: damage calculation, health system, hit detection, status effects, enemy AI, combat UI (health bars, damage numbers), death/respawn "Open world" implies: streaming/chunking, LOD system, fast travel, map/minimap, point of interest tracking, world state persistence "Multiplayer" implies: networking layer, lobby/matchmaking, state synchronization, anti cheat, network UI (ping, player list) "Crafting" implies: recipe database, ingredient gathering, crafting UI, success/failure mechanics, recipe discovery/learning "Dialogue" implies: dialogue tree system, dialogue UI, choice tracking, NPC state management, localization hooks "Progression" implies: XP system, level up mechanics, skill tree, unlock tracking, progression UI, progression save data Explain in conversation text why each implicit system is needed (with examples). Step 2c: User Review Present the enumeration organized by category. For each system, show: Name Category Brief description (1 sentence) Whether it was explicit (from concept) or implicit (inferred) Then use AskUserQuestion to capture feedback: "Are there systems missing from this list?" "Should any of these be combined or split?" "Are there systems listed that this game does NOT need?" Iterate until the user approves the enumeration. Phase 3: Dependency Mapping (Collaborative) For each system, determine what it depends on. A system "depends on" another if it cannot function without that other system existing first. Step 3a: Map Dependencies For each system, list its dependencies. Use these dependency heuristics: Input/output dependencies : System A produces data System B needs Structural dependencies : System A provides the framework System B plugs into UI dependencies : Every gameplay system has a corresponding UI system that depends on it (but UI is designed after the gameplay system) Step 3b: Sort by Dependency Order Arrange systems into layers: 1. Foundation : Systems with zero dependencies (designed and built first) 2. Core : Systems depending only on Foundation systems 3. Feature : Systems depending on Core systems 4. Presentation : UI and feedback systems that wrap gameplay systems 5. Polish : Meta systems, tutorials, analytics, accessibility Step 3c: Detect Circular Dependencies Check for cycles in the dependency graph. If found: Highlight them to the user Propose resolutions (interface abstraction, simultaneous design, breaking the cycle by defining a contract between the two systems) Step 3d: Present to User Show the dependency map as a layered list. Highlight: Any circular dependencies Any "bottleneck" systems (many others depend on them — these are high risk) Any systems with no dependents (leaf nodes — lower risk, can be designed late) Use AskUserQuestion to ask: "Does this dependency ordering look right? Any dependencies I'm missing or that should be removed?" Review mode check — apply before spawning TD SYSTEM BOUNDARY: solo → skip. Note: "TD SYSTEM BOUNDARY skipped — Solo mode." Proceed to priority assignment. lean → skip (not a PHASE GATE). Note: "TD SYSTEM BOUNDARY skipped — Lean mode." Proceed to priority assignment. full → spawn as normal. After dependency mapping is approved, spawn technical director via Task using gate TD SYSTEM BOUNDARY ( .claude/docs/director gates.md ) before proceeding to priority assignment. Pass: the dependency map summary, layer assignments, bottleneck systems list, any circular dependency resolutions. Present the assessment. If REJECT, revise the system boundaries with the user before moving to priority assignment. If CONCERNS, note them inline in the systems index and continue. Phase 4: Priority Assignment (Collaborative) Assign each system to a priority tier based on what milestone it's needed for. Step 4a: Auto Assign Based on Concept Use these heuristics for initial assignment: MVP : Systems mentioned in the concept's "Required for MVP" section, plus their Foundation layer dependencies Vertical Slice : Systems needed for a complete experience in one area Alpha : All remaining gameplay systems Full Vision : Polish, meta, and nice to have systems Step 4b: User Review Present the priority assignments in a table. For each tier, explain why systems were placed there. Use AskUserQuestion to ask: "Do these priority assignments match your vision? Which systems should be higher or lower priority?" Explain reasoning in conversation: "I placed [system] in MVP because the core loop requires it — without [system], the 30 second loop can't function." "Why" column guidance : When explaining why each system was placed in a priority tier, mix technical necessity with player experience reasoning. Do not use purely technical justifications like "Combat needs damage math" — connect to player experience where relevant. Examples of good "Why" entries: "Required for the core loop — without it, placement decisions have no consequence (Pillar 2: Placement is the Puzzle)" "Ballista's punch through identity is established here — this stat definition is what makes it feel different from Archer" "Foundation for all economy decisions — players must understand upgrade costs to make meaningful placement choices" Pure technical necessity ("X depends on Y") is insufficient alone when the system directly shapes player experience. Review mode check — apply before spawning PR SCOPE: solo → skip. Note: "PR SCOPE skipped — Solo mode." Proceed to writing the systems index. lean → skip (not a PHASE GATE). Note: "PR SCOPE skipped — Lean mode." Proceed to writing the systems index. full → spawn as normal. After priorities are approved, spawn producer via Task using gate PR SCOPE ( .claude/docs/director gates.md ) before writing the index. Pass: total system count per milestone tier, estimated implementation volume per tier (system count × average complexity), team size, stated project timeline. Present the assessment. If UNREALISTIC, offer to revise priority tier assignments before writing the index. If CONCERNS, note them and continue. Step 4c: Determine Design Order Combine dependency sort + priority tier to produce the final design order: 1. MVP Foundation systems first 2. MVP Core systems second 3. MVP Feature systems third 4. Vertical Slice Foundation/Core systems 5. ...and so on This is the order the team should write GDDs in. Phase 5: Create Systems Index (Write) Step 5a: Draft the Document Using the template at .claude/docs/templates/systems index.md , populate the systems index with all data from Phases 2 4: Fill the enumeration table Fill the dependency map Fill the recommended design order Fill the high risk systems Fill progress tracker (all systems "Not Started" initially, unless GDDs already exist) Step 5b: Approval Present a summary of the document: Total systems count by category MVP system count First 3 systems in the design order Any high risk items Ask: "May I write the systems index to design/gdd/systems index.md ?" Wait for approval. Write the file only after "yes." Review mode check — apply before spawning CD SYSTEMS: solo → skip. Note: "CD SYSTEMS skipped — Solo mode." Proceed to Phase 7 next steps. lean → skip (not a PHASE GATE). Note: "CD SYSTEMS skipped — Lean mode." Proceed to Phase 7 next steps. full → spawn as normal. After the systems index is written, spawn creative director via Task using gate CD SYSTEMS ( .claude/docs/director gates.md ). Pass: systems index path, game pillars and core fantasy (from design/gdd/game concept.md ), MVP priority tier system list. Present the assessment. If REJECT, revise the system set with the user before GDD authoring begins. If CONCERNS, record them in the systems index as a Creative Director Note at the top of the relevant tier section. Step 5c: Update Session State After writing, create production/session state/active.md if it does not exist, then update it with: Task: Systems decomposition Status: Systems index created File: design/gdd/systems index.md Next: Design individual system GDDs Verdict: COMPLETE — systems index written to design/gdd/systems index.md . If the user declined: Verdict: BLOCKED — user did not approve the write. Phase 6: Design Individual Systems (Handoff to /design system) This phase is entered when: The user says "yes" to designing systems after creating the index The user invokes /map systems [system name] The user invokes /map systems next Step 6a: Select the System If a system name was provided, find it in the systems index If next was used, pick the highest priority undesigned system (by design order) If the user just finished the index, ask: "Would you like to start designing individual systems now? The first system in the design order is [name]. Or would you prefer to stop here and come back later?" Use AskUserQuestion for: "Start designing [system name] now, pick a different system, or stop here?" Step 6b: Hand Off to /design system Once a system is selected, invoke the /design system [system name] skill. The /design system skill handles the full GDD authoring process: Gathers context from game concept, systems index, and dependency GDDs Creates a file skeleton immediately Walks through all 8 require

map-systems