diff --git a/.github/CODEOWNERS b/.github/CODEOWNERS
new file mode 100644
index 0000000..e73e427
--- /dev/null
+++ b/.github/CODEOWNERS
@@ -0,0 +1,7 @@
+# See https://docs.github.com/en/repositories/managing-your-repositorys-settings-and-features/customizing-your-repository/about-code-owners
+#
+# The spec is the source of truth for the protocol. All changes are
+# reviewed by stewards; substantive and breaking changes additionally
+# follow the comment-period process in GOVERNANCE.md.
+
+*       @fuax16
diff --git a/README.md b/README.md
index fc328fe..3a4476c 100644
--- a/README.md
+++ b/README.md
@@ -24,13 +24,32 @@ See [§4 of the spec](concept-and-spec.md#4-reference-implementation-plan) for t
 
 ## Contributing
 
-See [CONTRIBUTING.md](https://github.com/openagp/.github/blob/main/CONTRIBUTING.md) and [GOVERNANCE.md](https://github.com/openagp/.github/blob/main/GOVERNANCE.md) at the org level.
+See [CONTRIBUTING.md](https://github.com/openagp/.github/blob/main/CONTRIBUTING.md) and [GOVERNANCE.md](https://github.com/openagp/.github/blob/main/GOVERNANCE.md) at the org level. For routing — questions vs. bugs vs. spec changes — see [SUPPORT.md](https://github.com/openagp/.github/blob/main/SUPPORT.md).
 
 For spec changes:
-1. Open an issue describing the change and rationale.
+1. Open a [Spec change issue](https://github.com/openagp/spec/issues/new?template=spec_change.yml) describing the change and rationale.
 2. PR adds a decision record in `decisions/`.
 3. Substantive changes have a 2-week comment period; breaking changes have 4 weeks.
 
+### Local checks before opening a PR
+
+```bash
+# Validate every event fixture against schemas/event.json (same script CI runs)
+pip install "jsonschema>=4.21.0" "referencing>=0.34.0"
+# see .github/workflows/validate.yml for the exact validator
+
+# Run the cross-language test vectors against an SDK
+cd ../sdk-python && pytest tests/test_interop.py
+cd ../sdk-typescript && npm test -- interop
+cd ../cts && make vectors
+```
+
+If you're changing a schema or a test vector, **the SDKs and `agp-cts` must all stay green** — they share these inputs.
+
+### Questions
+
+Use [GitHub Discussions on this repo](https://github.com/openagp/spec/discussions) for design conversations and "how do I model X?" questions.
+
 ## License
 
 [CC BY 4.0](LICENSE) — you may share and adapt the spec for any purpose, including commercially, with attribution.