docs: clarify contribution guidelines

.coderabbit.yaml

@@ -0,0 +1,12 @@
+# yaml-language-server: $schema=https://coderabbit.ai/integrations/schema.v2.json
+
+reviews:
+  request_changes_workflow: false
+  slop_detection:
+    enabled: true
+
+knowledge_base:
+  code_guidelines:
+    enabled: true
+    filePatterns:
+      - 'CONTRIBUTING.md'

.github/pull_request_template.md

@@ -5,7 +5,8 @@
 ## ✅ Checklist
 
 - [ ] I have followed the steps in the [Contributing guide](https://github.com/TanStack/store/blob/main/CONTRIBUTING.md).
-- [ ] I have tested this code locally with `pnpm test:pr`.
+- [ ] I have tested code changes locally with `pnpm test:pr`, or these tests do not apply to this pull request.
+- [ ] I fully understand the code in this pull request, including any code generated with AI assistance.
 
 ## 🚀 Release Impact
 

AGENTS.md

@@ -0,0 +1,10 @@
+# Agent Instructions
+
+Before analyzing or changing this repository, read and follow
+[`CONTRIBUTING.md`](./CONTRIBUTING.md). Its contribution, development, testing,
+pull request, and changeset requirements apply to AI-assisted work as well as
+human-authored work.
+
+Keep every change focused on one topic. Understand and verify all generated
+code, run the required checks, and provide a concise pull request description
+that follows the repository template.

CONTRIBUTING.md

@@ -1,5 +1,23 @@
 # Contributing
 
+## Before You Start
+
+- Search the [open and closed issues](https://github.com/TanStack/store/issues?q=is%3Aissue) before reporting a bug. If it has not already been reported, use the [bug report template](https://github.com/TanStack/store/issues/new?template=bug_report.yml).
+- Search the [open and closed pull requests](https://github.com/TanStack/store/pulls?q=is%3Apr) before starting work to avoid duplicating an existing contribution.
+- Discuss significant features, API changes, and refactors with the maintainers in an issue before implementing them.
+
+## Pull Request Guidelines
+
+Every pull request must follow the [TanStack Store pull request template](.github/pull_request_template.md). Complete its description and checklist without removing or bypassing the required sections.
+
+- Keep each pull request focused on one change or topic. Pull requests that combine unrelated changes will be closed with a request to split them into separately reviewable contributions.
+- Write a concise description that clearly explains what changed and why. Follow the sections in the pull request template; a long, unstructured description makes a contribution harder to review.
+- You may use AI tools to help generate code, but you remain responsible for understanding, testing, and verifying every submitted change. Do not submit unreviewed, low-quality, or irrelevant generated code.
+- Do not mass-submit unrelated or low-quality AI-generated pull requests. We treat that behavior as spam and may close the pull requests, block the contributor, and report the GitHub account.
+- Every change that affects a published package must include a changeset. Create it with `pnpm changeset`; documentation, CI, and development-only changes do not require one.
+
+## Development Workflow
+
 - Clone the repo
   - `gh repo clone TanStack/store`
 - Ensure `node` is installed