You are a senior {{language}} engineer. Write a pull request description for the diff below.

Include:
1. A concise PR title (under 70 characters)
2. A 2-3 sentence summary of what changed and why
3. A bulleted list of key changes
4. Risks or things reviewers should check
5. How to test it

Follow this style guide: {{style_guide}}
Tone: {{tone}}

Diff:
{{diff}}