diff --git a/db/migrations/versions/20250604_162113_observation_session_as_string.py b/db/migrations/versions/20250604_162113_observation_session_as_string.py
new file mode 100644
index 0000000..bf35ff6
--- /dev/null
+++ b/db/migrations/versions/20250604_162113_observation_session_as_string.py
@@ -0,0 +1,39 @@
+"""observation session as string
+
+Revision ID: 58439dd3088b
+Revises: 77cdbfc882e2
+Create Date: 2025-06-04 16:21:13.610668
+
+"""
+
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = "58439dd3088b"
+down_revision: Union[str, None] = "77cdbfc882e2"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.alter_column(
+        "agent_observation",
+        "session_id",
+        existing_type=sa.UUID(),
+        type_=sa.Text(),
+        existing_nullable=True,
+    )
+
+
+def downgrade() -> None:
+    op.alter_column(
+        "agent_observation",
+        "session_id",
+        existing_type=sa.Text(),
+        type_=sa.UUID(),
+        existing_nullable=True,
+    )
diff --git a/src/memory/common/db/models/source_items.py b/src/memory/common/db/models/source_items.py
index f5a5d5a..cd77453 100644
--- a/src/memory/common/db/models/source_items.py
+++ b/src/memory/common/db/models/source_items.py
@@ -564,9 +564,7 @@ class AgentObservation(SourceItem):
     id = Column(
         BigInteger, ForeignKey("source_item.id", ondelete="CASCADE"), primary_key=True
     )
-    session_id = Column(
-        UUID(as_uuid=True)
-    )  # Groups observations from same conversation
+    session_id = Column(Text, nullable=True)
     observation_type = Column(
         Text, nullable=False
     )  # belief, preference, pattern, contradiction, behavior