fix: skip agent joins in blocks endpoint (#3226)

letta/server/rest_api/routers/v1/blocks.py

@@ -101,6 +101,14 @@ async def retrieve_block(
 @router.get("/{block_id}/agents", response_model=List[AgentState], operation_id="list_agents_for_block")
 async def list_agents_for_block(
     block_id: str,
+    include_relationships: list[str] | None = Query(
+        None,
+        description=(
+            "Specify which relational fields (e.g., 'tools', 'sources', 'memory') to include in the response. "
+            "If not provided, all relationships are loaded by default. "
+            "Using this can optimize performance by reducing unnecessary joins."
+        ),
+    ),
     server: SyncServer = Depends(get_letta_server),
     actor_id: Optional[str] = Header(None, alias="user_id"),
 ):
@@ -110,7 +118,9 @@ async def list_agents_for_block(
     """
     actor = await server.user_manager.get_actor_or_default_async(actor_id=actor_id)
     try:
-        agents = await server.block_manager.get_agents_for_block_async(block_id=block_id, actor=actor)
+        agents = await server.block_manager.get_agents_for_block_async(
+            block_id=block_id, include_relationships=include_relationships, actor=actor
+        )
         return agents
     except NoResultFound:
         raise HTTPException(status_code=404, detail=f"Block with id={block_id} not found")

letta/services/block_manager.py

@@ -286,14 +286,20 @@ class BlockManager:
 
     @trace_method
     @enforce_types
-    async def get_agents_for_block_async(self, block_id: str, actor: PydanticUser) -> List[PydanticAgentState]:
+    async def get_agents_for_block_async(
+        self,
+        block_id: str,
+        actor: PydanticUser,
+        include_relationships: Optional[List[str]] = None,
+    ) -> List[PydanticAgentState]:
         """
         Retrieve all agents associated with a given block.
         """
         async with db_registry.async_session() as session:
             block = await BlockModel.read_async(db_session=session, identifier=block_id, actor=actor)
             agents_orm = block.agents
-            return await asyncio.gather(*[agent.to_pydantic_async() for agent in agents_orm])
+            agents = await asyncio.gather(*[agent.to_pydantic_async(include_relationships=include_relationships) for agent in agents_orm])
+            return agents
 
     @trace_method
     @enforce_types