diff --git a/CLAUDE.md b/CLAUDE.md
index 54015d5..ff000b2 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -152,3 +152,4 @@ When editing CLAUDE.md or other markdown files, follow these rules to avoid lint
 - IntegrityChecker normalizes line endings for cross-platform hash consistency
 - StringEncoder uses XOR with expanded key for simple obfuscation (not encryption)
 - PHPUnit 11 uses PHP 8 attributes (`#[Test]`, `#[CoversClass]`) instead of annotations
+- OpenAPI spec (tmp/openapi.json) updated to v0.3.2 with signature header definitions