UE Code Authoring

Implement Unreal Engine C++ changes in the project's own style. Write the code with your own file tools, audit the result against what the user actually asked for, and use Rider only for what an IDE knows and grep does not: resolved symbols, reflection/UHT diagnostics, solution code style, and builds.

Rider is reached through a single MCP tool — execute_tool(command="<tool> --flag value ...").

Gate

1. Confirm the workspace is a UE project: Glob for *.uproject at the root. If there is none, stop and say the task must run from the UE project root.
2. Confirm the request needs C++ source changes. Blueprint-only or editor-only automation → stop.
3. Read only what the change needs: the .uproject, the relevant Source/<Module>/<Module>.Build.cs, and one or two nearby .h/.cpp files that already do the same kind of thing.

What "done" means

A change is done when two independent things hold, and they fail for different reasons:

1. Declared shape — the source carries the requested declarations, metadata, and guards.
2. Observed behaviour — the feature does the requested thing when something drives it.