---

name: prototype description: "Concept prototype before GDDs — throwaway HTML, Engine or Paper build, PROCEED/PIVOT/KILL/NOT ASSESSED. After /brainstorm and /setup-engine." argument-hint: "[concept-description] [--path html|engine|paper] [--review full|lean|solo] [--spike]" user-invocable: true allowed-tools: Read, Glob, Grep, Write, Edit, Bash, Agent, AskUserQuestion, Bash(bash "*/.claude/skills/prototype/../../hooks/yaml-helper.sh" resolve_config *) model: sonnet

!bash "${CLAUDE_SKILL_DIR}/../../hooks/yaml-helper.sh" resolve_config --keys review_mode,automation,workflow

Resolved above — use as-is; --review overrides review_mode for this run. No block → defaults in .claude/docs/config-resolution.md.

Prototype

Purpose

This is the concept prototype — a fast, throwaway build that answers one question: "Is this core idea actually fun to interact with?"

Default use — run right after /brainstorm and /setup-engine, before writing GDDs or architecture docs. Its verdict determines whether the concept is worth the investment of full design documentation.

Mid-production? You can also run this at any stage to test a specific mechanic, design change, or technical question. Pass --spike to activate spike mode: a lightweight ~4-hour build with no GDD prerequisites and no phase gate implications.

Already have GDDs and architecture complete? To validate the full game loop before committing to Production, run /vertical-slice instead.

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Phase 1: Define the Question

Read references/1-question.md now and follow it — this phase's steps are in that file, not here. Read it again if the conversation was compacted or resumed during this phase.

Phase 2: Load Concept Context

Read references/2-load-context.md now and follow it — this phase's steps are in that file, not here. Read it again if the conversation was compacted or resumed during this phase.

Phase 3: Choose the Prototype Path

Read references/3-choose-path.md now and follow it — this phase's steps are in that file, not here. Read it again if the conversation was compacted or resumed during this phase.

Phase 4: Plan the Prototype

Read references/4-plan.md now and follow it — this phase's steps are in that file, not here. Read it again if the conversation was compacted or resumed during this phase.

Phase 5: Implement

Read references/5-implement.md now and follow it — this phase's steps are in that file, not here. Read it again if the conversation was compacted or resumed during this phase.

Phase 6: Playtest Debrief

Read references/6-debrief.md now and follow it — this phase's steps are in that file, not here. Read it again if the conversation was compacted or resumed during this phase.

Phase 7: Generate Prototype Report

Read references/7-report.md now and follow it — this phase's steps are in that file, not here. Read it again if the conversation was compacted or resumed during this phase.

Phase 8: Creative Director Review

Read references/8-cd-review.md now and follow it — this phase's steps are in that file, not here. Read it again if the conversation was compacted or resumed during this phase.

Phase 9: Summary and Next Steps

Read references/9-summary.md now and follow it — this phase's steps are in that file, not here. Read it again if the conversation was compacted or resumed during this phase.

Spike Mode

Triggered by: --spike flag OR "Mid-production spike" entry choice in Phase 1.

Read references/spike-mode.md now and follow it — this phase's steps are in that file, not here. Read it again if the conversation was compacted or resumed during this phase.

Important Constraints

• Prototype code must NEVER import from production source files
• Production code must NEVER import from prototype directories
• If the recommendation is PROCEED, production implementation is written from scratch — prototype code is never refactored into production
• Total effort is hard-capped at 1 day (concept prototypes test one mechanic)
• Test ONE mechanic — if scope grows, stop and simplify the question
• No polish. No menus, no game over, no music, no UI unless it IS the mechanic
• If stuck after 2 hours of engine iteration, reframe the question or switch paths
• 3 PIVOT iterations → force a KILL decision. If this is the third time the same concept has produced a PIVOT verdict, the concept likely doesn't work. Ask: "Is this the right idea, or am I in the sunk cost trap?" A new concept prototyped fresh will almost always beat a fourth iteration of a struggling one.
• Building 2-3 different concept variants and picking the best one is a healthier strategy than iterating one concept to death. Natural selection between prototypes beats willpower.
• Networked/multiplayer games: A local prototype cannot validate the feel of a networked mechanic. Latency fundamentally changes how combat, movement, and prediction feel — a prototype running at 0ms local will feel entirely different at 80ms network delay. Use a local prototype to validate that the mechanic is interesting. Do not use it as evidence that it feels good under real network conditions. Network feel requires real peers or simulated latency (e.g., throttle tools, network condition simulators).