diff --git a/pyproject.toml b/pyproject.toml
index d8a0aa7a5..785d96c88 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -124,6 +124,7 @@ trim-title-prefixes = ["[ty]"]
 [tool.rooster.section-labels]
 "Breaking changes" = ["breaking"]
 "Preview features" = ["preview"]
+"Diagnostics" = ["diagnostics"]
 "Bug fixes" = ["bug"]
 "LSP server" = ["server"]
 "CLI" = ["cli"]