It knows the project before you explain it.
Engine, version, language, project root, and engine-specific rules are loaded into every task. Fresh folder? BIGGI can scaffold the project first.
GAME LOOP ONLINE
An AI agent that can play your game.
BIGGI works beyond the codebase. It opens the engine, reads the console, inspects scenes, repairs what broke, and runs the game again until there is evidence.
Unity 2021.3 → Unity 6Godot 4.xMIT open source
One continuous loop · VS Code + CLI
From prompt to proof, without the copy-paste ritual.
It crosses into the running engine.
A warm Unity editor bridge or a deterministic Godot runner gives the agent real compile status, console output, scene state, tests, screenshots, and profiler data.
- Runs the scene and reads structured errors
- Queries static or live runtime trees
- Stops cleanly when the task or session ends
It follows the bug into the scene.
A stack trace is only half the story. BIGGI maps failures back to the exact node, GameObject, prefab, missing resource, or unassigned serialized field—and can repair structured scene data without blind text edits.
NullReferenceExceptionSpawner.enemyPrefab is unassigned in Level2.unity
It plays the result, then shows its work.
Replay input, invoke explicit game actions, watch semantic state across frames, guard invariants, and carry the same tracked scenario into CI. Success means a passing run with evidence, not a confident paragraph.
contract actionsinvariant guardswatch timelines
The marquee loop
The bug is in your scene, not your code.
BIGGI reads the exception, finds the component, inspects the loaded scene, wires the missing reference through Unity's serialization APIs, and replays the failing scenario.
One loop. Five engine-aware tools. A result you can review.
Deep where it matters
Built with the engines, not pasted on top.
Capabilities are explicit. BIGGI tells you what it can verify in the current project.
U
Unity Game Loop
The running editor is the fast path.
Compile autopilot, console and play-mode control, safe scene and prefab edits, project-owned state, action, and invariant contracts, Animator/NavMesh/physics observation, EditMode/PlayMode tests, percentile profiling, and scenario replay.
2021.3 LTS → Unity 6G
Godot Game Loop
Headless verification that understands scenes.
Runs, structured console parsing, GUT and gdUnit results, .tscn-safe scene edits, live tree queries, screenshots, profiling, scripted input, and scene-aware root causes.
Godot 4.x · GDScriptUnreal, Bevy, MonoGame, LÖVE, Phaser, Three.js, Babylon.js, PixiJS, Excalibur, Kaplay, and Matter.js get automatic project detection and game-development context today.
Two places. One runtime.
Stay in your editor. Or never leave the terminal.
01 / VS CODE
Run several ideas without tangling your branch.
Chat, approvals, reviewable diffs, snapshots, and Agent Manager sessions isolated in git worktrees—including parallel versions with different models.
Explore the VS Code extension →02 / CLI
Make the game loop scriptable.
Use the same agents and engine adapters from the TUI, a one-shot command, or CI. JSON and JUnit evidence make playtests part of the build.
Explore the CLI →Games are systems in motion, not folders full of code.
Read why we're building BIGGI →Field manual
The useful questions.
What makes BIGGI different from a general coding agent?
BIGGI can cross the boundary between source code and the running game. In supported Unity and Godot projects it can run the engine, inspect scenes, edit structured data, test, profile, capture screenshots, and replay gameplay before it claims a change works. Unity projects can also expose bounded state, invariants, and explicit actions so the agent works with project-owned meaning instead of guessing at arbitrary runtime fields.
Which engines have the full Game Loop?
Unity 2021.3 LTS and newer, including Unity 6, and Godot 4.x have deep Game Loop adapters today. Unreal, Bevy, MonoGame, LÖVE, Phaser, Three.js, Babylon.js, PixiJS, and other web engines still get automatic detection, engine context, and specialized game-development agents without pretending every runtime capability exists everywhere.
Does it work without a BIGGI account?
Yes. The VS Code extension and CLI are MIT licensed. Bring an API key for your preferred provider or use a local model. The optional BIGGI gateway offers one account and one key for 500+ models.
Can it create a game project from an empty folder?
Yes. game_new can scaffold a ready-to-run Unity or Godot project, detect projects one folder below the workspace, and hand the new project directly to the Game Loop.
Can I use the same playtests in CI?
Yes. Unity scenarios can live in .biggi/playtests and run through the editor bridge or batch mode with JSON, JUnit, screenshots, and stable exit codes. Godot playtests and test conventions also run headlessly.
READY WHEN YOU ARE
Give the agent a game it can actually run.
Open source. Bring any model. Start in VS Code or the terminal.