Game Concept

Reply in the project conversation language (CLAUDE.md → Language); code, identifiers, paths and commit messages stay in English.

Template .claude/docs/templates/game-concept.md. Reference threejs-webgames.md. In the commands below, <hooks> is .claude/hooks/ in copy mode and ${CLAUDE_PLUGIN_ROOT}/hooks/ in plugin mode.

Phase 1: Pitch and loop

Questions: genre, the player's "verb", session (minutes), platform (mobile web first?), single/multiplayer, references. Three core-loop variants with "why it is fun to repeat".

Phase 2: Mechanics, progression, content

Rules with parameters (mark which live in data, not code); a difficulty-curve table; MVP volume vs full version.

Phase 3: Feasibility

Engine with justification (3D → three.js, WebGPU with WebGL2 fallback; 2D → PixiJS/Phaser; versions from threejs-webgames.md); budget: 16.6 ms frame, draw calls, memory, first load on 4G; networking (multiplayer → server-authoritative on Go, tick rate); saves; spikes to test risks (e.g. "1000 instances on a mid-range phone"). threejs-engineer/web-game-engineer via Task — risk assessment for their part (in parallel).

Phase 4: Accessibility, metrics, prototype

Accessibility settings; retention metrics; prototype plan: what playability validates first, timeline, the "fun" criterion — measurable (sessions, minutes, a question to N testers), so gate can record a result, not an opinion.

Phase 4b: gate — the prototype go/no-go

/game-concept gate runs only this phase, after the first playable slice and before backend/multiplayer investment. The catalog step prototype-gate and /help look for its artefact.

1. Read §11 of docs/specs/game-concept.md (the measurable "fun" criterion).
2. Ask for the measured result against it (playtest notes, numbers).
3. Record GO | NO-GO | PIVOT (what changes) with the evidence in production/releases/gate-prototype.md and as a "Result" block under §11, after "May I write?" — one AskUserQuestion: write (Recommended) · show the draft/diff first · not now. After the "write" answer: touch .claude/.write-consent.
4. After the write, the Phase 6 commit gate (docs: prototype gate <GO|NO-GO|PIVOT>, staging production/releases/gate-prototype.md and docs/specs/game-concept.md).
5. Hand-off — one AskUserQuestion. GO → /create-stories for the vertical slice's feature (Recommended when no stories exist) · /dev-story S-NNN (Recommended when the stories exist — name the first Ready one) · stop here. NO-GO/PIVOT → the next step is a concept revision, not the next feature: /game-concept again for the sections the result names (Recommended) · /brainstorm when the loop itself failed · stop here.

Phase 5: Write

"May I write docs/specs/game-concept.md?" — one AskUserQuestion: write (Recommended) · show the draft/diff first · not now. Propose an engine ADR (/architecture-decision). After the "write" answer: touch .claude/.write-consent (rule 7 — the consent-guard hook checks the marker).

Phase 6: Commit (documents lane)

Right after the write, one commit gate (rule 7 (4), .claude/docs/git-workflow.md § Documents): one AskUserQuestion offering docs: game concept, staging exactly the written files — docs/specs/game-concept.md (for gate: the message and files Phase 4b step 4 names). Record the gate before asking — <hooks>session-state.sh set Gate "/game-concept Phase 6: commit?" — and clear it after the answer (<hooks>session-state.sh set Gate "—").

• On the default branch when no story work is in progress.
• When HEAD is a story branch, name it and offer: switch to the default branch and commit there (Recommended — a pipeline-wide document) · commit here (the document belongs to this story) · leave uncommitted.
• Code, configs, workflows and scripts never ride the docs: commit.

Nothing is committed without the answer.

Verdict: APPROVED | NEEDS REVISION | GO | NO-GO | PIVOT. Next step — one AskUserQuestion: /product-spec (light) (Recommended) · /architecture-decision (engine) · prototype via /dev-story. After gate, the hand-off of Phase 4b step 5 instead.