diff --git a/agents-api/agents_api/routers/agents/list_agents.py b/agents-api/agents_api/routers/agents/list_agents.py
index aa6986d0d..a24f0667c 100644
--- a/agents-api/agents_api/routers/agents/list_agents.py
+++ b/agents-api/agents_api/routers/agents/list_agents.py
@@ -30,7 +30,9 @@ async def list_agents(
         offset=offset,
         sort_by=sort_by,
         direction=direction,
-        metadata_filter=metadata_filter.model_dump(mode="json"),
+        metadata_filter=metadata_filter.model_dump(mode="json")
+        if metadata_filter
+        else {},
     )
 
     return ListResponse[Agent](items=agents)
diff --git a/agents-api/agents_api/routers/docs/list_docs.py b/agents-api/agents_api/routers/docs/list_docs.py
index 0cd823919..f342f4b4b 100644
--- a/agents-api/agents_api/routers/docs/list_docs.py
+++ b/agents-api/agents_api/routers/docs/list_docs.py
@@ -32,7 +32,9 @@ async def list_user_docs(
         offset=offset,
         sort_by=sort_by,
         direction=direction,
-        metadata_filter=metadata_filter.model_dump(mode="json"),
+        metadata_filter=metadata_filter.model_dump(mode="json")
+        if metadata_filter
+        else {},
     )
 
     return ListResponse[Doc](items=docs)
@@ -58,7 +60,9 @@ async def list_agent_docs(
         offset=offset,
         sort_by=sort_by,
         direction=direction,
-        metadata_filter=metadata_filter.model_dump(mode="json"),
+        metadata_filter=metadata_filter.model_dump(mode="json")
+        if metadata_filter
+        else {},
     )
 
     return ListResponse[Doc](items=docs)
diff --git a/agents-api/agents_api/routers/sessions/list_sessions.py b/agents-api/agents_api/routers/sessions/list_sessions.py
index ae011fb18..157b9f681 100644
--- a/agents-api/agents_api/routers/sessions/list_sessions.py
+++ b/agents-api/agents_api/routers/sessions/list_sessions.py
@@ -29,7 +29,9 @@ async def list_sessions(
         offset=offset,
         sort_by=sort_by,
         direction=direction,
-        metadata_filter=metadata_filter.model_dump(mode="json"),
+        metadata_filter=metadata_filter.model_dump(mode="json")
+        if metadata_filter
+        else {},
     )
 
     return ListResponse[Session](items=sessions)