Ask an AI coding assistant to write Unity or Unreal code and it will confidently generate method signatures that don't exist, reference deprecated APIs, and mix up version-specific behaviors. The documentation surface is enormous — tens of thousands of classes, methods, and properties across multiple engine versions — and LLMs trained on internet data inevitably hallucinate the details.
Codeturion (io.github.Codeturion) built a matched pair of servers that solve this by pre-indexing the full API surface into local databases:
Unity API MCP
unity-api-mcp (29 stars) indexes the Unity API across three engine versions — Unity 2022, 2023, and Unity 6. Each version database is 18–24 MB and contains 32,000–42,000 API records. Five searchable tools cover keyword search, exact signature lookup, namespace resolution, full class reference cards, and deprecation warnings. Queries return in under 15 milliseconds.
Unreal API MCP
unreal-api-mcp (21 stars) applies the same approach to Unreal Engine's C++ API. Supports UE 5.5, 5.6, and 5.7. The databases are larger — 43–50 MB each — covering 114,724 API records across 1,019 modules for UE 5.7. Exact lookups run in under 1 millisecond; keyword searches in under 5 milliseconds. No engine installation required — databases download automatically on first use.
The Token Efficiency Claim
The README for unity-api-mcp includes token usage benchmarks: 4x fewer tokens than a skilled agent performing its own API research, and 11x fewer than a naive agent. This matters because game engine API lookups are one of the most token-intensive parts of AI-assisted game development — the agent often burns through thousands of tokens searching documentation before writing a single line of gameplay code.
What to Know
Both servers are built by Fuat Cankoseoglu, who also published codesurface (16 stars) for general code analysis. The game engine servers use PolyForm Noncommercial 1.0.0 — free for personal and non-commercial use, commercial licensing available separately. This is a notable licensing choice: the servers are open source but not permissively licensed. Commercial game studios would need to negotiate terms.
Game development is a natural fit for MCP. The documentation surfaces are vast, version-specific, and poorly served by general-purpose LLM training data. One developer building API servers for both major engines is a smart strategic play — and the sub-millisecond lookup times mean the agent barely pauses to check its work.
Scores: 60–61. No flags. PolyForm Noncommercial 1.0.0.
Sources: Codeturion — GitHub · unity-api-mcp — repo · unreal-api-mcp — repo · Scorecard: io.github.Codeturion (score 61)