Tag releases

AGENTS.md

@@ -147,6 +147,14 @@ Two rules about all of the above:
    per-source `stats.json` files.
 4. Prepend the release notes to `CHANGELOG.md` under a new `## vX.Y.Z (date)`
    heading. History is append-only — never rewrite earlier releases.
+5. Tag the commit where the docs and the artifacts agree, and push the tag:
+   ```bash
+   git tag -a vX.Y.Z <commit> -m "vX.Y.Z stable: <docs> documents / <tokens> tokens / <n> sources"
+   git push origin vX.Y.Z
+   ```
+   A release with no tag can only be cited by hash, and every later doc fix
+   makes that hash a worse citation than the one before it — which is how
+   `v0.2.5` ended up cited three different ways. Tag it once and cite the tag.
 
 ## Push to Hugging Face