Document installed Windows toolchain discovery

docs/GAMEPLAY_PROGRAMMING/external-process-languages/toolchains.md

@@ -11,6 +11,20 @@ installs every selected item through Windows Package Manager. Lua, JavaScript, a
 HTML/CSS are bundled. Additional toolchains can be installed later using **Rustic Game
 Engine > Language Toolchain Manager** in the Start menu or by rerunning Setup.
 
+On Windows, Rustic checks the editor's PATH first, then the saved system and user
+PATH on each dependency check. For C/C++, it also checks LLVM's registered install
+folder and the standard LLVM folders under Program Files and
+`%LOCALAPPDATA%\Programs`. An existing LLVM installation does not need to be
+reinstalled or added to PATH when it is found in one of those locations. After
+installing a toolchain, return to the editor and press **Play** to check again.
+
+If C/C++ is still reported missing, check that the LLVM `bin` folder contains
+`clang.exe` for C and `clang++.exe` for C++. For an unregistered custom installation,
+add its `bin` folder to your Windows user or system PATH and press **Play** again.
+A WinGet package listing alone does not confirm that the required compiler files
+are present. Other compiler, SDK, or linker errors appear in the Console after
+discovery succeeds; repair the relevant toolchain if compilation fails.
+
 Setup uses one PowerShell process without allocating a console for all selected
 toolchains and skips tools that are already installed. A bundled GUI setup helper
 launches PowerShell and the agent integration installer under the original user's

docs/Scripting/scriptingC/current-limits-and-diagnosis.md

@@ -13,7 +13,10 @@ have three seconds to finish. An exception, invalid engine value, process exit,
 timeout, or rejected call disables the behavior. Failed build/reload validation
 keeps the last good instance running.
 
-- **Toolchain unavailable:** check PATH in the editor's environment, then restart it.
+- **Toolchain unavailable:** check that `clang.exe` (Windows) or your chosen C
+  compiler exists. On Windows, add a custom compiler folder to the saved user/system
+  PATH and press **Play** again. On other platforms, restart the editor after a PATH
+  change.
 - **Nothing moves:** check attachment, owner transform, Play focus, and held KeyW.
 - **Property rejected:** declare it in the editor and preserve its type.
 - **Wrong parent:** pass the ID returned by Find, not the path string.

docs/Scripting/scriptingC/setup-and-attachment.md

@@ -2,7 +2,10 @@
 
 [Back to C](/docs/scripting/c).
 
-1. Install Clang, GCC, or MSVC on PATH (C17). Restart the editor after changing PATH.
+1. Install Clang, GCC, or MSVC (C17). On Windows, Rustic also checks the saved
+   system/user PATH and registered or standard LLVM install folders. After installation
+   or a saved PATH change, press **Play** to recheck. On other platforms, put the
+   compiler on PATH before starting the editor.
    Check the Project Manager’s **Settings** language tools and the editor **Console** for discovery errors. Contributors with a source checkout can optionally run `cargo xtask doctor` from `Engine/`.
 2. Open your game project and scene. Select a **Part** object for this movement example.
 3. Use **Programming > Object Component Script** and select C.

docs/Scripting/scriptingCpp.md

@@ -5,7 +5,10 @@ compiles each `.cc`, `.cpp`, or `.cxx` behavior as C++20, and runs one isolated
 process per instance. The header parses protocol requests and exposes typed native
 helpers, so ordinary game code should not emit JSON.
 
-Install `clang++`, `g++`, or MSVC `cl` on `PATH`. Clang/GCC builds use `-Wall
+Install `clang++`, `g++`, or MSVC `cl` on `PATH`. On Windows, Rustic also checks
+the saved system/user PATH and registered or standard LLVM install folders; press
+**Play** after installation to recheck without reinstalling LLVM. A custom compiler
+folder can be added to the saved user/system PATH. Clang/GCC builds use `-Wall
 -Wextra -Werror -std=c++20`; MSVC uses `/nologo /W4`. The editor also writes an
 IntelliSense copy to `.rustic/generated/programming/rustic.hpp`, but Rustic supplies
 the authoritative temporary copy when building. Never edit or vendor the generated