diff --git a/configs/named_values.go b/configs/named_values.go
index fa51c76ae..b88f06bf2 100644
--- a/configs/named_values.go
+++ b/configs/named_values.go
@@ -14,7 +14,7 @@ import (
 )
 
 // A consistent detail message for all "not a valid identifier" diagnostics.
-const badIdentifierDetail = "A name must start with a letter and may contain only letters, digits, underscores, and dashes."
+const badIdentifierDetail = "A name must start with a letter or underscore and may contain only letters, digits, underscores, and dashes."
 
 // Variable represents a "variable" block in a module or file.
 type Variable struct {