[docs] Add lightweight AI assisted contribution policy (#30947)

Signed-off-by: Mark McLoughlin <markmc@redhat.com>

docs/contributing/README.md

@@ -187,6 +187,25 @@ Using `-s` with `git commit` will automatically add this header.
     - **VSCode**: Open the [Settings editor](https://code.visualstudio.com/docs/configure/settings)
       and enable the `Git: Always Sign Off` (`git.alwaysSignOff`) field.
 
+### AI Assisted Contributions
+
+When AI tools provide non-trivial assistance in generating or modifying code, you must:
+
+1. **Review thoroughly**: You remain responsible for all code you submit. Review and understand AI-generated code with the same care as code you write manually.
+2. **Disclose in PR**: Always mention when a pull request includes AI-generated code. Add a note in the PR description.
+3. **Mark commits**: Add attribution using commit trailers such as `Co-authored-by:` (other projects use `Assisted-by:` or `Generated-by:`). For example:
+
+   ```text
+   Your commit message here
+
+   Co-authored-by: GitHub Copilot
+   Co-authored-by: Claude
+   Co-authored-by: gemini-code-assist
+   Signed-off-by: Your Name <your.email@example.com>
+   ```
+
+AI-assisted code must meet all quality standards: proper testing, documentation, adherence to style guides, and thorough review. Attribution helps reviewers evaluate contributions in context and maintains legal clarity for the project.
+
 ### PR Title and Classification
 
 Only specific types of PRs will be reviewed. The PR title is prefixed

docs/governance/process.md

@@ -135,6 +135,14 @@ PRs requires at least one committer review and approval. If the code is covered
 
 In case where CI didn't pass due to the failure is not related to the PR, the PR can be merged by the lead maintainers using "force merge" option that overrides the CI checks.
 
+### AI Assisted Contributions
+
+AI tools can accelerate development, but contributors remain fully responsible for all code they submit. Like the Developer Certificate of Origin, this policy centers on accountability: contributors must believe they have the right to submit their contribution under vLLM's open source license, regardless of how the code was created.
+
+All AI-assisted contributions must meet the same quality, testing, and review standards as any other code. Contributors must review and understand AI-generated code before submission—just make sure it is good code.
+
+Attribution preserves legal clarity and community trust. Contributors must disclose AI assistance in pull requests and mark commits with appropriate trailers (e.g. `Co-authored-by:`).
+
 ### Slack
 
 Contributors are encouraged to join `#pr-reviews` and `#contributors` channels.