- IN26-section GDDDesign contract: loop, verbs, UI, art and audio briefs, budgets, acceptance tests
- 01Schema-validated manifestGDD becomes JSON checked against a schema, plus a list of open decisions
- 02Staged agentCursor + Unity MCP: asset intake → scaffold → greybox, one stage at a time
- 03Human play gateA developer plays the greybox: is the mechanic fun? Tweak or approve
- 04Deterministic auditUnity Editor validators, Project Auditor, tests, import checks, handoff report
- OUTPlayable scaffoldFeature folder, scenes and handoff JSON; a human runs the build
21minGDD to playable scaffold on one prototype (commit timestamps)
20/22Acceptance tests passing at that prototype's handoff
5Prototypes run through the pipeline
3maxQA cycles per generated asset, then keep the closest
● Example runGDD in 12:31 → scaffold committed 12:52
● AI pipeline · Unity · 2026
AI game-prototyping pipeline
I built an AI game-prototyping system for Unity: give it a game design document and a staged agent turns it into a playable, audited scaffold, with a human deciding whether the game is fun before any polish happens.
How it works
- Contracts over prompts: a 26-section GDD template and a JSON-schema manifest make the agent's output checkable and resumable.
- Staged agent: Cursor driving the Unity Editor through Unity MCP, one stage at a time (ingest, asset intake, scaffold, greybox, presentation, providers, audit, handoff), with only the tools each step needs switched on.
- Human play gate: after greybox, a developer plays it. Art and menus wait until the mechanic is fun. The AI validates; a human builds.
- Deterministic audit tools: Unity Editor validators, Project Auditor, EditMode/PlayMode tests and a handoff report do the steps an LLM should not improvise.
- Multimodal QA: generated 2D art is checked by vision; Gemini listens to every generated sound effect against its brief, with a hard cap of 3 cycles.
- Self-improving: pilot failures became fixes on the main template, and its rules and guides were adopted into live production games.
Example: one prototype
- Intake
- GDD dropped in at 12:31 PM
- Scaffold
- Manifest, asset questionnaire and feature-folder scaffold committed by 12:52 PM (21 minutes)
- Handoff
- 20 of 22 acceptance tests pass, 2 recorded deviations
Stack
Unity 6C#URPCursorUnity MCPJSON SchemaGemini audio QAProject Auditor
Figures are calendar timestamps and test results, not measured effort. No speed multiple is claimed.
Genopets
Gamerize Dictionary
Dino Hunter 3D: Shooting Games
Bus Driving Simulator Game USA
