diff --git a/docs/contributing.md b/docs/contributing.md
index 7bc862a5be7..bf1969d3abe 100644
--- a/docs/contributing.md
+++ b/docs/contributing.md
@@ -19,6 +19,43 @@ again. In other words, the Google CLA is not scoped to a specific project. If
 you sign the Google CLA, it applies to other Google open-source projects as
 well (including future projects).
 
+### Use of AI and LLM tools
+
+You are welcome to use generative AI and LLM tools ("AI") to help create
+contributions as long as you review and edit what it produces to follow the
+project guidelines. However, please do not use AI and agents to communicate with
+the community, including Discord, issues, and pull requests.
+
+1. **You are the author.** AI is a tool you may use while creating a
+   contribution, but you are the author. If a substantial part of your
+   contribution is generated by AI, please disclose this by adding an
+   `Assisted-by` trailer at the end of the commit message. Examples:
+
+   ```
+   Assisted-by: Claude Opus 4.8
+   Assisted-by: Kimi K3
+   Assisted-by: GPT 5.6 Sol
+   ```
+
+2. **You must understand what you are contributing.** If you do not understand
+   what AI has generated, please do not contribute it. If you would like help
+   understanding code that is already part of the project, please ask in Discord
+   or GitHub Discussions.
+
+3. **We want to talk to you, not your AI.** When communicating with the
+   community, do not paste the output from AI or allow an AI agent to post for you.
+   This includes, but is not limited to:
+
+   - Creating pull requests and responding to feedback
+   - Creating or replying to GitHub issues
+   - Posting messages in Discord and GitHub Discussions
+
+   Avoid using AI to generate commit messages. Writing the commit message
+   yourself ensures you understand and agree with what you're writing.
+
+   It is acceptable to use AI to translate to English, but please also include
+   your writing in its original language.
+
 ### Commit guidelines
 
 Unlike many GitHub projects (but like many VCS projects), we care more about the