feat: Add message_buffer_autoclear field to Agent (#978)

alembic/versions/7980d239ea08_add_stateless_option_for_agentstate.py

@@ -0,0 +1,36 @@
+"""Add message_buffer_autoclear option for AgentState
+
+Revision ID: 7980d239ea08
+Revises: dfafcf8210ca
+Create Date: 2025-02-12 14:02:00.918226
+
+"""
+
+from typing import Sequence, Union
+
+import sqlalchemy as sa
+
+from alembic import op
+
+# revision identifiers, used by Alembic.
+revision: str = "7980d239ea08"
+down_revision: Union[str, None] = "dfafcf8210ca"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    # Add the column with a temporary nullable=True so we can backfill
+    op.add_column("agents", sa.Column("message_buffer_autoclear", sa.Boolean(), nullable=True))
+
+    # Backfill existing rows to set message_buffer_autoclear to False where it's NULL
+    op.execute("UPDATE agents SET message_buffer_autoclear = false WHERE message_buffer_autoclear IS NULL")
+
+    # Now, enforce nullable=False after backfilling
+    op.alter_column("agents", "message_buffer_autoclear", nullable=False)
+
+
+def downgrade() -> None:
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_column("agents", "message_buffer_autoclear")
+    # ### end Alembic commands ###

letta/orm/agent.py

@@ -1,7 +1,7 @@
 import uuid
 from typing import TYPE_CHECKING, List, Optional
 
-from sqlalchemy import JSON, Index, String
+from sqlalchemy import JSON, Boolean, Index, String
 from sqlalchemy.orm import Mapped, mapped_column, relationship
 
 from letta.orm.block import Block
@@ -62,6 +62,11 @@ class Agent(SqlalchemyBase, OrganizationMixin):
     # Tool rules
     tool_rules: Mapped[Optional[List[ToolRule]]] = mapped_column(ToolRulesColumn, doc="the tool rules for this agent.")
 
+    # Stateless
+    message_buffer_autoclear: Mapped[bool] = mapped_column(
+        Boolean, doc="If set to True, the agent will not remember previous messages. Not recommended unless you have an advanced use case."
+    )
+
     # relationships
     organization: Mapped["Organization"] = relationship("Organization", back_populates="agents")
     tool_exec_environment_variables: Mapped[List["AgentEnvironmentVariable"]] = relationship(
@@ -146,6 +151,7 @@ class Agent(SqlalchemyBase, OrganizationMixin):
             "project_id": self.project_id,
             "template_id": self.template_id,
             "base_template_id": self.base_template_id,
+            "message_buffer_autoclear": self.message_buffer_autoclear,
         }
 
         return self.__pydantic_model__(**state)

letta/schemas/agent.py

@@ -85,6 +85,12 @@ class AgentState(OrmMetadataBase, validate_assignment=True):
     template_id: Optional[str] = Field(None, description="The id of the template the agent belongs to.")
     base_template_id: Optional[str] = Field(None, description="The base template id of the agent.")
 
+    # An advanced configuration that makes it so this agent does not remember any previous messages
+    message_buffer_autoclear: bool = Field(
+        False,
+        description="If set to True, the agent will not remember previous messages (though the agent will still retain state via core memory blocks and archival/recall memory). Not recommended unless you have an advanced use case.",
+    )
+
     def get_agent_env_vars_as_dict(self) -> Dict[str, str]:
         # Get environment variables for this agent specifically
         per_agent_env_vars = {}
@@ -146,6 +152,10 @@ class CreateAgent(BaseModel, validate_assignment=True):  #
     project_id: Optional[str] = Field(None, description="The id of the project the agent belongs to.")
     template_id: Optional[str] = Field(None, description="The id of the template the agent belongs to.")
     base_template_id: Optional[str] = Field(None, description="The base template id of the agent.")
+    message_buffer_autoclear: bool = Field(
+        False,
+        description="If set to True, the agent will not remember previous messages (though the agent will still retain state via core memory blocks and archival/recall memory). Not recommended unless you have an advanced use case.",
+    )
 
     @field_validator("name")
     @classmethod
@@ -216,6 +226,10 @@ class UpdateAgent(BaseModel):
     project_id: Optional[str] = Field(None, description="The id of the project the agent belongs to.")
     template_id: Optional[str] = Field(None, description="The id of the template the agent belongs to.")
     base_template_id: Optional[str] = Field(None, description="The base template id of the agent.")
+    message_buffer_autoclear: Optional[bool] = Field(
+        None,
+        description="If set to True, the agent will not remember previous messages (though the agent will still retain state via core memory blocks and archival/recall memory). Not recommended unless you have an advanced use case.",
+    )
 
     class Config:
         extra = "ignore"  # Ignores extra fields

letta/services/agent_manager.py

@@ -123,6 +123,7 @@ class AgentManager:
             project_id=agent_create.project_id,
             template_id=agent_create.template_id,
             base_template_id=agent_create.base_template_id,
+            message_buffer_autoclear=agent_create.message_buffer_autoclear,
         )
 
         # If there are provided environment variables, add them in
@@ -185,6 +186,7 @@ class AgentManager:
         project_id: Optional[str] = None,
         template_id: Optional[str] = None,
         base_template_id: Optional[str] = None,
+        message_buffer_autoclear: bool = False,
     ) -> PydanticAgentState:
         """Create a new agent."""
         with self.session_maker() as session:
@@ -202,6 +204,7 @@ class AgentManager:
                 "project_id": project_id,
                 "template_id": template_id,
                 "base_template_id": base_template_id,
+                "message_buffer_autoclear": message_buffer_autoclear,
             }
 
             # Create the new agent using SqlalchemyBase.create
@@ -263,6 +266,7 @@ class AgentManager:
                 "project_id",
                 "template_id",
                 "base_template_id",
+                "message_buffer_autoclear",
             }
             for field in scalar_fields:
                 value = getattr(agent_update, field, None)

tests/helpers/utils.py

@@ -151,3 +151,7 @@ def comprehensive_agent_checks(agent: AgentState, request: Union[CreateAgent, Up
         assert all(
             any(rule.tool_name == req_rule.tool_name for rule in agent.tool_rules) for req_rule in request.tool_rules
         ), f"Tool rules mismatch: {agent.tool_rules} != {request.tool_rules}"
+
+    # Assert message_buffer_autoclear
+    if not request.message_buffer_autoclear is None:
+        assert agent.message_buffer_autoclear == request.message_buffer_autoclear

tests/test_managers.py

@@ -447,6 +447,7 @@ def comprehensive_test_agent_fixture(server: SyncServer, default_user, print_too
         tool_rules=[InitToolRule(tool_name=print_tool.name)],
         initial_message_sequence=[MessageCreate(role=MessageRole.user, content="hello world")],
         tool_exec_environment_variables={"test_env_var_key_a": "test_env_var_value_a", "test_env_var_key_b": "test_env_var_value_b"},
+        message_buffer_autoclear=True,
     )
     created_agent = server.agent_manager.create_agent(
         create_agent_request,
@@ -601,6 +602,7 @@ def test_update_agent(server: SyncServer, comprehensive_test_agent_fixture, othe
         message_ids=["10", "20"],
         metadata={"train_key": "train_value"},
         tool_exec_environment_variables={"test_env_var_key_a": "a", "new_tool_exec_key": "n"},
+        message_buffer_autoclear=False,
     )
 
     last_updated_timestamp = agent.updated_at