diff --git a/.github/scripts/verify_tui_core_boundary.py b/.github/scripts/verify_tui_core_boundary.py
index 8c5c340079..0abd88d994 100644
--- a/.github/scripts/verify_tui_core_boundary.py
+++ b/.github/scripts/verify_tui_core_boundary.py
@@ -17,7 +17,7 @@ TUI_MANIFEST = TUI_ROOT / "Cargo.toml"
 FORBIDDEN_PACKAGE = "codex-core"
 CODEX_PROTOCOL_PACKAGE = "codex-protocol"
 CODEX_PROTOCOL_MESSAGE = "references `codex_protocol::protocol`"
-IDENTIFIER = r"(?:r#)?[A-Za-z_][A-Za-z0-9_]*"
+IDENTIFIER = r"(?:r#)?[^\W\d]\w*"
 PROTOCOL_IDENTIFIER = r"(?:r#)?protocol"
 TOKEN_SEPARATOR = r"\s*"
 REQUIRED_TOKEN_SEPARATOR = r"\s+"