add AI policy

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,9 +1,23 @@
 <!--
 
-Thanks for contributing a pull request! Please make sure you have read the
-[contribution guidelines](https://mne.tools/dev/development/contributing.html)
+Thanks for contributing a pull request! Please make sure you have read
+[CONTRIBUTING.md](https://github.com/mne-tools/mne-python/blob/main/CONTRIBUTING.md)
+and the [detailed contribution guidelines](https://mne.tools/dev/development/contributing.html)
 before submitting.
 
+If you used AI to help prepare this pull request, please pay special attention to
+our **Policy on AI Assistance in Contributions** in
+[CONTRIBUTING.md](https://github.com/mne-tools/mne-python/blob/main/CONTRIBUTING.md).
+Here are some examples of what we expect for "tool, manner, and scope" disclosure:
+
+- "I implemented the code changes myself, and Claude Sonnet 4.6 wrote the test."
+- "I prompted Gemini 3.1 Pro to get a first draft implementation, then refined it
+  manually until I was satisfied."
+- "I wrote the code and asked Kimi K2.5 to write the docstring for me."
+- "I fed GPT 5.4 the paper where the algorithm is described, and asked it to implement
+  it for me. Then I had it write an example script using the `sample` dataset, and I
+  wrote the narrative text of the tutorial myself."
+
 Please be aware that we are a loose team of volunteers so patience is
 necessary. Assistance handling other issues is very welcome. We value
 all user contributions, no matter how minor they are. If we are slow to

CONTRIBUTING.md

@@ -7,3 +7,17 @@ Users and contributors to MNE-Python are expected to follow our [code of conduct
 
 The [contributing guide](https://mne.tools/dev/development/contributing.html) has details on the preferred contribution workflow
 and the recommended system configuration for a smooth contribution/development experience.
+
+
+Policy on AI Assistance in Contributions
+----------------------------------------
+Contributing to MNE-Python requires human judgment, contextual understanding, domain knowledge, and familiarity with MNE-Python’s structure and goals. It is not suitable for automatic processing by AI tools.
+
+You may not submit issues or pull requests generated by fully-automated tools. Maintainers reserve the right, at their sole discretion, to close such submissions and to block any account responsible for them.
+
+Review all code or documentation changes assisted by AI tools and make sure you understand all changes and can explain them on request, before submitting them under your name. Do not submit any AI-generated code that you haven’t personally reviewed, understood and tested. Please pay special attention to whether AI-assisted code reproduces specific passages for specialized algorithms, as this may risk license violations.
+
+Please do not paste AI generated text in the description of issues, PRs or in comments as this makes it harder for reviewers to assess your contribution.
+If you used AI tools, state so in your PR description and disclose the tools you have used, and the manner and scope of their assistance (see PR template for examples).
+
+PRs that appear to violate this policy will be closed without review. AI usage is an evolving issue with serious repercussions far beyond the scientific software ecosystem. The MNE-Python project reserves the right to change or reverse this policy given the developments in these areas.