Add AI contribution policy guidance

BRANDING.md

@@ -59,7 +59,7 @@ Given the open nature of Istio, you may use the Istio trademark to refer to the
 
 -   “Istio Day”
 
-The Istio Steering Committee understands the community need for a conformance standard, which would authorize expanded use of the Istio mark. We plan to implement a conformance standard at a future date, and commit to creating a Conformance Task Force no later than Q4 2021. 
+The Istio Steering Committee understands the community need for a conformance standard, which would authorize expanded use of the Istio mark. Until the project publishes a conformance standard, any use of the Istio Trademarks that implies compatibility, certification, endorsement, or conformance requires prior written permission from Istio Steering.
 
 The Istio Steering Committee reserves the right to deny specific use cases if, in the opinion of the Steering Committee, the use case would not be in the best interest of the Istio Community.
 

CONTRIBUTING.md

@@ -15,6 +15,7 @@ same process and are given the same level of review.
 - [Contributing a feature](#contributing-a-feature)
 - [Setting up to contribute to Istio](#setting-up-to-contribute-to-istio)
 - [Pull requests](#pull-requests)
+- [AI-assisted contributions](#ai-assisted-contributions)
 - [Issues](#issues)
 - [Promote your company on istio.io](#promote-your-company-on-istioio)
 - [Tell the world you're using Istio](#tell-the-world-youre-using-istio)
@@ -148,6 +149,34 @@ See [Writing Good Pull Requests](https://github.com/istio/istio/wiki/Writing-Goo
 pull requests, and [Reviewing Pull Requests](https://github.com/istio/istio/wiki/Reviewing-Pull-Requests) for the PR review
 we use.
 
+## AI-assisted contributions
+
+Contributors may use AI tools to help write, explain, test, or review
+contributions, but the person submitting the contribution remains responsible
+for the full content of the issue, pull request, comment, or other engagement.
+
+When AI assistance is substantial to the final contribution, disclose that use
+in the pull request or issue description. Maintainers may ask for clarification
+about which parts were AI-assisted, how the output was checked, and whether the
+contributor understands and can maintain the change.
+
+AI-assisted contributions must meet the same standards as any other
+contribution:
+
+- The contributor must verify that code builds, tests pass, and documentation is
+  accurate.
+- The contributor must review generated content for correctness, security,
+  licensing, originality, and fit with Istio's design and community standards.
+- The contributor must be able to respond to review feedback and explain the
+  technical choices in their own words.
+- AI-generated comments or issue replies must be relevant, respectful, and based
+  on a real understanding of the discussion.
+
+Maintainers may close, hide, mark as spam, or request changes to AI-assisted
+content that is low quality, misleading, duplicative, unsafe, unverifiable, or
+otherwise inconsistent with the [Code of Conduct](CODE-OF-CONDUCT.md) and
+[Team Values](VALUES.md).
+
 ## Issues
 
 [GitHub issues](https://github.com/istio/istio/issues/new/choose) can be used to report bugs or submit feature requests.