Epic says it is using AI coding tools across Unreal Engine and Fortnite development, with claimed gains that include fewer bugs and a major graphics-layer rewrite completed faster. This is not just a debate about AI-made game assets: the tools are being used to change how the software itself is built.
Watch Desk analysis
What happened
Epic executive vice-president of development Marcus Wassmer told PC Gamer that the company uses tools including Claude Code and Codex across its development work. He said almost all development underway is in teams connected to Fortnite, Unreal Editor for Fortnite and Unreal Engine 6.
Wassmer cited several examples: AI-assisted work almost eliminated a longstanding class of non-deterministic cooking bugs, accelerated shader compression work that reduced patch sizes, and helped rewrite a significant portion of the D3D12 rendering layer. He estimated that last job would take one engineer three to six weeks; Epic completed it in about a week, with a reported CPU-time improvement and fewer bugs.
Why it matters
These examples put a more useful measure on AI in game development than the usual argument over generated artwork. Epic is describing AI as an engineering tool, with potential effects on development time, bugs and the performance or size of what players download.
The figures and results are Epic’s account, reported by PC Gamer, rather than an independent measurement. Even so, the examples make the practical stakes clear: AI-assisted coding could affect the tools developers use and the updates players receive, not only what appears on screen.
Our read
The striking part is not the phrase “vibe coding”; it is the claim that engineers are guiding iterative work rather than asking a model to produce an engine in one go. If the reported gains hold up, this is a consequential change to software development practice, not a shortcut that makes human engineering disappear. Epic’s results are worth watching, but one company’s account is not yet an industry-wide benchmark.
What to watch
- Whether Epic shares further detail on how it measured the bug, shader and CPU-time improvements.
- Whether Unreal Engine developers see practical benefits in tools or updates built with this workflow.
- Whether other large software and game teams report comparable gains, or different trade-offs.
Discussion spark: If AI tools help engineers ship fewer bugs and faster performance improvements, should studios disclose their use even when the tools are working behind the scenes?
Sources and evidence
Watch Desk is operated by WittyWires as an independent cross-cutting AI news tracker. It does not speak for the organisations or people it covers.