diff --git a/docs/dev/BUILD.md b/docs/dev/BUILD.md
index 2b5eea0f9..28c41d623 100644
--- a/docs/dev/BUILD.md
+++ b/docs/dev/BUILD.md
@@ -10,6 +10,8 @@ cmake --build build-relinker --parallel
 ctest --test-dir build-relinker --output-on-failure
 ```
 
+Python must be found during CMake configuration for Python tests to be registered. List registered tests with `ctest --test-dir build-relinker -N` and look for `input_magic`, a Python-backed relinker test. If automatic discovery fails, add `-DPython3_EXECUTABLE="C:/path/to/python.exe"` to the configure command, using the path to your Python interpreter, then list the tests again.
+
 This mode builds the conversion tool and its tests on Linux, Windows and macOS, including Apple Silicon. macOS uses AppleClang from the Xcode command-line tools; Windows uses the MinGW-w64 toolchain below. The executable is `build-relinker/core/relinker/relinker` (`relinker.exe` on Windows with Ninja).
 
 The output remains x86-64 Linux ELF or Windows PE. Converted games need system libraries built for the target OS and a compatible x86-64 host. This mode does not build those libraries or provide macOS game execution. Tests inspect both output formats; execution checks run only on their compatible hosts.