diff --git a/ecu_framework/__init__.py b/ecu_framework/__init__.py
index 9e6104f..9ef1128 100644
--- a/ecu_framework/__init__.py
+++ b/ecu_framework/__init__.py
@@ -1,3 +1,12 @@
+"""
+ECU Tests framework package.
+
+Provides:
+- config: YAML configuration loader and types
+- lin: LIN interface abstraction and adapters (mock and BabyLIN)
+
+Package version is exposed as __version__.
+"""
 __all__ = [
     "config",
     "lin",
diff --git a/ecu_framework/lin/__init__.py b/ecu_framework/lin/__init__.py
index 0f06b86..60df3a5 100644
--- a/ecu_framework/lin/__init__.py
+++ b/ecu_framework/lin/__init__.py
@@ -1,3 +1,12 @@
+"""
+LIN interface package.
+
+Exports:
+- LinInterface, LinFrame: core abstraction and frame type
+- MockBabyLinInterface: mock implementation for fast, hardware-free tests
+
+Real hardware adapter (BabyLIN) is available in babylin.py.
+"""
 from .base import LinInterface, LinFrame
 from .mock import MockBabyLinInterface