diff --git a/docs/developer_guide/contribution_guide.md b/docs/developer_guide/contribution_guide.md
index 4f23b0f1a..a15c03c75 100644
--- a/docs/developer_guide/contribution_guide.md
+++ b/docs/developer_guide/contribution_guide.md
@@ -143,9 +143,10 @@ Users listed in [CI_PERMISSIONS.json](https://github.com/sgl-project/sglang/blob
 - Avoid code duplication. If the same code snippet (more than five lines) appears multiple times, extract it into a shared function.
 - Minimize device synchronization. Reduce expensive CPU-GPU synchronization operations, such as `tensor.item()` or `tensor.cpu()`, whenever possible. Use vectorized code.
 - Prioritize extreme efficiency. SGLang is a runtime, and most of your code runs on the critical path for every request. Optimize all minor overheads as much as possible, especially in the model forward code.
-  - A common pattern is some runtime checks in the model forward pass (e.g., [this](https://github.com/sgl-project/sglang/blob/f1b0eda55c2c4838e8ab90a0fac7fb1e3d7064ab/python/sglang/srt/models/deepseek_v2.py#L486-L491)). These are very likely the same for every layer. Please cache the result as a single boolean value whenever possible.
+  - A common pattern is some runtime checks in the model forward pass (e.g., [this](https://github.com/sgl-project/sglang/blob/f1b0eda55c2c4838e8ab90a0fac7fb1e3d7064ab/python/sglang/srt/models/deepseek_v2.py#L486-L491)). These are very likely the same for every layer. Please cache the result as a single boolean value in `__init__` whenever possible.
 - Make functions as pure as possible. Avoid in-place modification of arguments.
 - Keep files concise. If a file exceeds 2,000 lines of code, split it into multiple smaller files. (e.g., `scheduler.py`, `scheduler_output_processor_mixin.py`)
+- In a file, put core data structures at the top of the file. Put utility functions at the bottom of the file.
 - Keep tests run fast.
   - If a single test file run longer than 500 seconds, split it into multiple smaller files (e.g., `test_eagle_infer_a.py`, `test_eagle_infer_b.py`).
   - If a single job in a github workflow runs longer than 30 mins, split it into smaller jobs/steps.