diff --git a/src/astraeus_common/error/__init__.py b/src/astraeus_common/error/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/src/astraeus_common/error/body_not_found.py b/src/astraeus_common/error/body_not_found.py
new file mode 100644
index 0000000..c6c1692
--- /dev/null
+++ b/src/astraeus_common/error/body_not_found.py
@@ -0,0 +1,2 @@
+class BodyNotFound(Exception):
+    pass
diff --git a/src/astraeus_common/error/sync_state_not_found.py b/src/astraeus_common/error/sync_state_not_found.py
new file mode 100644
index 0000000..b555a28
--- /dev/null
+++ b/src/astraeus_common/error/sync_state_not_found.py
@@ -0,0 +1,2 @@
+class SyncStateNotFound(Exception):
+    pass
diff --git a/src/astraeus_common/error/system_not_found.py b/src/astraeus_common/error/system_not_found.py
new file mode 100644
index 0000000..72319c9
--- /dev/null
+++ b/src/astraeus_common/error/system_not_found.py
@@ -0,0 +1,2 @@
+class SystemNotFound(Exception):
+    pass