diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index b5a14ba..aa9a7e0 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -24,7 +24,7 @@ uDuck Registry is a directory of Microduck behavior policies. A contribution is
 
 3. The filename must match the lowercase kebab-case `id`. Use `community_experimental` unless the upstream project or a pull request provides physical-run evidence. Use `claimed_hardware` when the author reports a physical run that the registry has not reproduced. Use `verified_hardware` only for an upstream-supported behavior or a submission with physical evidence.
 
-4. Point `artifacts.onnx.url` at the canonical ONNX file. The registry links to that file and does not copy policy weights into the repository.
+4. Point `artifacts.onnx.url` at the canonical ONNX file. Use `https://huggingface.co/...` or `https://raw.githubusercontent.com/...`; these are the artifact hosts accepted by registry validation. The registry links to that file and does not copy policy weights into the repository.
 
 5. Run the checks and rebuild the catalog:
 
@@ -32,6 +32,8 @@ uDuck Registry is a directory of Microduck behavior policies. A contribution is
    pnpm check
    ```
 
+   This refreshes `README.md` and `public/registry.json`; include both generated files in your pull request.
+
 6. Open a pull request with the upstream source, license, hardware requirements, and any evidence supporting the verification label.
 
 ### Preview media
diff --git a/README.md b/README.md
index b6a460e..34c4ea8 100644
--- a/README.md
+++ b/README.md
@@ -71,7 +71,7 @@ The same snapshot is in [`public/registry.json`](public/registry.json). The stat
 
 ## Contributing
 
-Generate a starting descriptor with `pnpm --silent new-behavior id=my-move name="My Move" category=locomotion author="Your Name"`, run `pnpm check`, then open a pull request. See [CONTRIBUTING.md](CONTRIBUTING.md) for the descriptor shape and review expectations.
+Generate a starting descriptor with `pnpm --silent new-behavior id=my-move name="My Move" category=locomotion author="Your Name"`, run `pnpm check`, include the refreshed `README.md` and `public/registry.json`, then open a pull request. See [CONTRIBUTING.md](CONTRIBUTING.md) for the descriptor shape and review expectations.
 
 ## Attribution and license