Can Claude Code × Unity MCP Build an Anime-Style Open World? A 65-Minute Field Test

The starting point was a comment on the previous video: 'Claude Code automates more, and Unity MCP lets the AI drive Unity directly.' Wire MCP in, and you can ask the AI to place objects and adjust the scene without touching Unity yourself.

Last time, the creator asked Gemini, GPT, and Claude whether to use agents at that stage and all three said 'don't — you'll lose track of what's happening,' so it was skipped. This time, with a stronger working knowledge of Unity, the creator commits to running Claude Code + Unity MCP at full strength, targeting an anime-style open-world background as the concrete goal.

Some wins were not designed in. Hand a reference image to the Grass Manager and say 'match the colours,' and Claude Code uses the tool to do the colour matching on its own. When the result felt too bright, asking for 'something more subdued' produced an instant correction. The final palette landed with slightly lower saturation but a satisfying anime feel.

Terrain tooling showed the same pattern. An auto-depress-the-road tool was generated; on terrain where the creator had hand-brushed bumps and dips, naïve application would have flattened the brushwork. After being told 'please respect those,' Claude Code returned a version that explicitly preserved the brush-made bumps. AI behavior that doesn't trample your manual work matters a lot for real production.

The practical conclusion is honest. Not everything benefits from AI. Claude Code + MCP is slow for small interactions — sometimes skipping the AI is faster. The realistic split is to do the easy or fast bits yourself (treat it as a tool), and hand the big work or repetitive work to Claude. Implement one enemy and then say 'do the rest of the cast the same way' — that's where the agent really earns its keep.

The biggest superpower is bug tracing. Claude Code can step inside Unity, run isolation experiments, and pin down root causes with a depth that's hard to match manually. Complex systems, repetition, and debugging — those three are where Claude Code is genuinely strong. The final anime open-world background looked clearly better than the previous stage. The field-building tool itself took serious work to build, so the creator is shipping it on the Asset Store at a few thousand yen — 'cheaper than building it yourself again, even with Claude helping.'