All environment variables must be documented in the central env_var.md file with clear descriptions of their purpose, acceptable values, and effects. Use consistent naming patterns that reflect the subsystem they configure (e.g., MXNET_CUDNN_*, MXNET_MKLDNN_*) and avoid introducing new variables when existing ones can serve the same purpose. Example: ```cpp // Good - Uses consistent naming and is documented // In code: const bool brgemm_disabled = dmlc::GetEnv("MXNET_MKLDNN_DISABLE_BRGEMM_FC", true); // In docs/static_site/src/pages/api/faq/env_var.md: // MXNET_MKLDNN_DISABLE_BRGEMM_FC=[true|false] - Disable BRGEMM algorithm in fully connected layers when using MKLDNN backend. Default is true. // Bad - Introduces new variable without documentation static bool use_new_dep_engine = dmlc::GetEnv("MXNET_ASYNC_GPU_ENGINE", false); // Instead, reuse existing variable: // static bool use_new_dep_engine = (dmlc::GetEnv("MXNET_ENGINE_TYPE", "") == "AsyncGPU"); ``` When adding new configuration options: 1. Check if an existing variable can be extended instead of creating a new one 2. Follow the subsystem naming prefix pattern (MXNET_[SUBSYSTEM]_*) 3. Document the variable in env_var.md with its default value and purpose 4. For enum-like options, document all valid values and their effects