diff --git a/README.md b/README.md
index e801da5..f883eed 100644
--- a/README.md
+++ b/README.md
@@ -5,13 +5,21 @@ A small, personal C library for learning and experimentation.
 
 ## Features
 
-All the features listed are Thread-safe.
+Most core containers use internal locks for single-object operations.
+Cross-object operations can still require caller-side synchronization.
 
 - Hashmaps
 - Strings
 - Circular queues
 - Vectors
 - Stack
+- Set
+
+### Notes
+
+- Hashmap keys/values are copied as raw bytes (`memcpy`) using `key_size`/`value_size`.
+- For C-string keys, provide a readable key buffer of at least `key_size` bytes.
+- The set module is basic and intentionally minimal.
 
 ## Installation