Add CONTRIBUTING.md for AXP spec repo

CONTRIBUTING.md

@@ -1,16 +1,54 @@
-# Contributing
+# Contributing to the AXP Specification
 
-Thank you for your interest in contributing.
+Thank you for your interest in the AXP protocol specification. Contributions
+from the community help us build a better standard.
 
-## Development Workflow
+AXME is in alpha -- breaking changes may occur. We especially welcome feedback
+on API ergonomics.
 
-1. Open an issue to discuss changes.
-2. Create a branch from main.
-3. Add tests for all behavioral changes.
-4. Ensure CI passes before opening a PR.
+## Ways to Contribute
 
-## Pull Request Requirements
+- Propose schema changes or new lifecycle states
+- Report spec inconsistencies or ambiguities
+- Improve documentation clarity
+- Add conformance test cases
 
-- Clear summary and rationale
-- Test coverage for new behavior
-- Backward compatibility notes where applicable
+## Reporting Issues
+
+Open a GitHub Issue at <https://github.com/AxmeAI/axme-spec/issues>. Include:
+
+- Which section of the spec is affected
+- What the inconsistency or problem is
+- A suggested correction, if you have one
+
+## Proposing Changes
+
+1. Fork the repository.
+2. Create a branch from `main` (e.g., `feat/add-lifecycle-state`).
+3. Make your changes.
+4. Open a pull request against `main` with a clear description of what changed
+   and why.
+
+## Style Guidelines
+
+- Write in clear, precise English. Avoid jargon where a simpler term works.
+- Schema definitions must be valid JSON Schema.
+- Use consistent terminology -- refer to existing spec sections for naming
+  conventions.
+- Keep examples minimal but complete.
+
+## Review Process
+
+All spec changes are reviewed for correctness, clarity, and backward
+compatibility. Expect discussion -- protocol changes affect every SDK and
+implementation downstream. Small fixes (typos, broken links) are merged
+quickly; schema or lifecycle changes require broader review.
+
+## Code of Conduct
+
+Be respectful and constructive. We are building a shared standard and
+productive disagreement is welcome.
+
+## Contact
+
+Questions or feedback: hello@axme.ai