feat: enable configuration of response_char_limit for tools (#2207)

alembic/versions/a91994b9752f_add_column_to_tools_table_to_contain_.py

@@ -0,0 +1,39 @@
+"""add column to tools table to contain function return limit return_char_limit
+
+Revision ID: a91994b9752f
+Revises: e1a625072dbf
+Create Date: 2024-12-09 18:27:25.650079
+
+"""
+
+from typing import Sequence, Union
+
+import sqlalchemy as sa
+
+from alembic import op
+from letta.constants import FUNCTION_RETURN_CHAR_LIMIT
+
+# revision identifiers, used by Alembic.
+revision: str = "a91994b9752f"
+down_revision: Union[str, None] = "e1a625072dbf"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.add_column("tools", sa.Column("return_char_limit", sa.Integer(), nullable=True))
+
+    # Populate `return_char_limit` column
+    op.execute(
+        f"""
+        UPDATE tools
+        SET return_char_limit = {FUNCTION_RETURN_CHAR_LIMIT}
+        """
+    )
+
+
+def downgrade() -> None:
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_column("tools", "return_char_limit")
+    # ### end Alembic commands ###

letta/agent.py

@@ -801,7 +801,13 @@ def _handle_ai_response(
                     # but by default, we add a truncation safeguard to prevent bad functions from
                     # overflow the agent context window
                     truncate = True
-                function_response_string = validate_function_response(function_response, truncate=truncate)
+
+                # get the function response limit
+                tool_obj = [tool for tool in self.agent_state.tools if tool.name == function_name][0]
+                return_char_limit = tool_obj.return_char_limit
+                function_response_string = validate_function_response(
+                    function_response, return_char_limit=return_char_limit, truncate=truncate
+                )
                 function_args.pop("self", None)
                 function_response = package_function_response(True, function_response_string)
                 function_failed = False

letta/client/client.py

@@ -11,6 +11,7 @@
     BASE_TOOLS,
     DEFAULT_HUMAN,
     DEFAULT_PERSONA,
+    FUNCTION_RETURN_CHAR_LIMIT,
 )
 from letta.data_sources.connectors import DataConnector
 from letta.functions.functions import parse_source_code
@@ -200,18 +201,12 @@ def load_composio_tool(self, action: "ActionType") -> Tool:
         raise NotImplementedError
 
     def create_tool(
-        self,
-        func,
-        name: Optional[str] = None,
-        tags: Optional[List[str]] = None,
+        self, func, name: Optional[str] = None, tags: Optional[List[str]] = None, return_char_limit: int = FUNCTION_RETURN_CHAR_LIMIT
     ) -> Tool:
         raise NotImplementedError
 
     def create_or_update_tool(
-        self,
-        func,
-        name: Optional[str] = None,
-        tags: Optional[List[str]] = None,
+        self, func, name: Optional[str] = None, tags: Optional[List[str]] = None, return_char_limit: int = FUNCTION_RETURN_CHAR_LIMIT
     ) -> Tool:
         raise NotImplementedError
 
@@ -222,6 +217,7 @@ def update_tool(
         description: Optional[str] = None,
         func: Optional[Callable] = None,
         tags: Optional[List[str]] = None,
+        return_char_limit: int = FUNCTION_RETURN_CHAR_LIMIT,
     ) -> Tool:
         raise NotImplementedError
 
@@ -1465,6 +1461,7 @@ def create_tool(
         func: Callable,
         name: Optional[str] = None,
         tags: Optional[List[str]] = None,
+        return_char_limit: int = FUNCTION_RETURN_CHAR_LIMIT,
     ) -> Tool:
         """
         Create a tool. This stores the source code of function on the server, so that the server can execute the function and generate an OpenAI JSON schemas for it when using with an agent.
@@ -1473,6 +1470,7 @@ def create_tool(
             func (callable): The function to create a tool for.
             name: (str): Name of the tool (must be unique per-user.)
             tags (Optional[List[str]], optional): Tags for the tool. Defaults to None.
+            return_char_limit (int): The character limit for the tool's return value. Defaults to FUNCTION_RETURN_CHAR_LIMIT.
 
         Returns:
             tool (Tool): The created tool.
@@ -1481,7 +1479,9 @@ def create_tool(
         source_type = "python"
 
         # call server function
-        request = ToolCreate(source_type=source_type, source_code=source_code, name=name, tags=tags)
+        request = ToolCreate(source_type=source_type, source_code=source_code, name=name, return_char_limit=return_char_limit)
+        if tags:
+            request.tags = tags
         response = requests.post(f"{self.base_url}/{self.api_prefix}/tools", json=request.model_dump(), headers=self.headers)
         if response.status_code != 200:
             raise ValueError(f"Failed to create tool: {response.text}")
@@ -1492,6 +1492,7 @@ def create_or_update_tool(
         func: Callable,
         name: Optional[str] = None,
         tags: Optional[List[str]] = None,
+        return_char_limit: int = FUNCTION_RETURN_CHAR_LIMIT,
     ) -> Tool:
         """
         Creates or updates a tool. This stores the source code of function on the server, so that the server can execute the function and generate an OpenAI JSON schemas for it when using with an agent.
@@ -1500,6 +1501,7 @@ def create_or_update_tool(
             func (callable): The function to create a tool for.
             name: (str): Name of the tool (must be unique per-user.)
             tags (Optional[List[str]], optional): Tags for the tool. Defaults to None.
+            return_char_limit (int): The character limit for the tool's return value. Defaults to FUNCTION_RETURN_CHAR_LIMIT.
 
         Returns:
             tool (Tool): The created tool.
@@ -1508,7 +1510,9 @@ def create_or_update_tool(
         source_type = "python"
 
         # call server function
-        request = ToolCreate(source_type=source_type, source_code=source_code, name=name, tags=tags)
+        request = ToolCreate(source_type=source_type, source_code=source_code, name=name, return_char_limit=return_char_limit)
+        if tags:
+            request.tags = tags
         response = requests.put(f"{self.base_url}/{self.api_prefix}/tools", json=request.model_dump(), headers=self.headers)
         if response.status_code != 200:
             raise ValueError(f"Failed to create tool: {response.text}")
@@ -1521,6 +1525,7 @@ def update_tool(
         description: Optional[str] = None,
         func: Optional[Callable] = None,
         tags: Optional[List[str]] = None,
+        return_char_limit: int = FUNCTION_RETURN_CHAR_LIMIT,
     ) -> Tool:
         """
         Update a tool with provided parameters (name, func, tags)
@@ -1530,6 +1535,7 @@ def update_tool(
             name (str): Name of the tool
             func (callable): Function to wrap in a tool
             tags (List[str]): Tags for the tool
+            return_char_limit (int): The character limit for the tool's return value. Defaults to FUNCTION_RETURN_CHAR_LIMIT.
 
         Returns:
             tool (Tool): Updated tool
@@ -1541,7 +1547,14 @@ def update_tool(
 
         source_type = "python"
 
-        request = ToolUpdate(description=description, source_type=source_type, source_code=source_code, tags=tags, name=name)
+        request = ToolUpdate(
+            description=description,
+            source_type=source_type,
+            source_code=source_code,
+            tags=tags,
+            name=name,
+            return_char_limit=return_char_limit,
+        )
         response = requests.patch(f"{self.base_url}/{self.api_prefix}/tools/{id}", json=request.model_dump(), headers=self.headers)
         if response.status_code != 200:
             raise ValueError(f"Failed to update tool: {response.text}")
@@ -2726,6 +2739,7 @@ def create_tool(
         name: Optional[str] = None,
         tags: Optional[List[str]] = None,
         description: Optional[str] = None,
+        return_char_limit: int = FUNCTION_RETURN_CHAR_LIMIT,
     ) -> Tool:
         """
         Create a tool. This stores the source code of function on the server, so that the server can execute the function and generate an OpenAI JSON schemas for it when using with an agent.
@@ -2735,6 +2749,7 @@ def create_tool(
             name: (str): Name of the tool (must be unique per-user.)
             tags (Optional[List[str]], optional): Tags for the tool. Defaults to None.
             description (str, optional): The description.
+            return_char_limit (int): The character limit for the tool's return value. Defaults to FUNCTION_RETURN_CHAR_LIMIT.
 
         Returns:
             tool (Tool): The created tool.
@@ -2755,6 +2770,7 @@ def create_tool(
                 name=name,
                 tags=tags,
                 description=description,
+                return_char_limit=return_char_limit,
             ),
             actor=self.user,
         )
@@ -2765,6 +2781,7 @@ def create_or_update_tool(
         name: Optional[str] = None,
         tags: Optional[List[str]] = None,
         description: Optional[str] = None,
+        return_char_limit: int = FUNCTION_RETURN_CHAR_LIMIT,
     ) -> Tool:
         """
         Creates or updates a tool. This stores the source code of function on the server, so that the server can execute the function and generate an OpenAI JSON schemas for it when using with an agent.
@@ -2774,6 +2791,7 @@ def create_or_update_tool(
             name: (str): Name of the tool (must be unique per-user.)
             tags (Optional[List[str]], optional): Tags for the tool. Defaults to None.
             description (str, optional): The description.
+            return_char_limit (int): The character limit for the tool's return value. Defaults to FUNCTION_RETURN_CHAR_LIMIT.
 
         Returns:
             tool (Tool): The created tool.
@@ -2791,6 +2809,7 @@ def create_or_update_tool(
                 name=name,
                 tags=tags,
                 description=description,
+                return_char_limit=return_char_limit,
             ),
             actor=self.user,
         )
@@ -2802,6 +2821,7 @@ def update_tool(
         description: Optional[str] = None,
         func: Optional[callable] = None,
         tags: Optional[List[str]] = None,
+        return_char_limit: int = FUNCTION_RETURN_CHAR_LIMIT,
     ) -> Tool:
         """
         Update a tool with provided parameters (name, func, tags)
@@ -2811,6 +2831,7 @@ def update_tool(
             name (str): Name of the tool
             func (callable): Function to wrap in a tool
             tags (List[str]): Tags for the tool
+            return_char_limit (int): The character limit for the tool's return value. Defaults to FUNCTION_RETURN_CHAR_LIMIT.
 
         Returns:
             tool (Tool): Updated tool
@@ -2821,6 +2842,7 @@ def update_tool(
             "tags": tags,
             "name": name,
             "description": description,
+            "return_char_limit": return_char_limit,
         }
 
         # Filter out any None values from the dictionary

letta/orm/tool.py

@@ -30,6 +30,7 @@ class Tool(SqlalchemyBase, OrganizationMixin):
     __table_args__ = (UniqueConstraint("name", "organization_id", name="uix_name_organization"),)
 
     name: Mapped[str] = mapped_column(doc="The display name of the tool.")
+    return_char_limit: Mapped[int] = mapped_column(nullable=True, doc="The maximum number of characters the tool can return.")
     description: Mapped[Optional[str]] = mapped_column(nullable=True, doc="The description of the tool.")
     tags: Mapped[List] = mapped_column(JSON, doc="Metadata tags used to filter tools.")
     source_type: Mapped[ToolSourceType] = mapped_column(String, doc="The type of the source code.", default=ToolSourceType.json)
@@ -45,19 +46,16 @@ class Tool(SqlalchemyBase, OrganizationMixin):
 
 
 # Add event listener to update tool_name in ToolsAgents when Tool name changes
-@event.listens_for(Tool, 'before_update')
+@event.listens_for(Tool, "before_update")
 def update_tool_name_in_tools_agents(mapper, connection, target):
     """Update tool_name in ToolsAgents when Tool name changes."""
     state = target._sa_instance_state
-    history = state.get_history('name', passive=True)
+    history = state.get_history("name", passive=True)
     if not history.has_changes():
         return
-    
+
     # Get the new name and update all associated ToolsAgents records
     new_name = target.name
     from letta.orm.tools_agents import ToolsAgents
-    connection.execute(
-        ToolsAgents.__table__.update().where(
-            ToolsAgents.tool_id == target.id
-        ).values(tool_name=new_name)
-    )
+
+    connection.execute(ToolsAgents.__table__.update().where(ToolsAgents.tool_id == target.id).values(tool_name=new_name))

letta/schemas/tool.py

@@ -2,6 +2,7 @@
 
 from pydantic import Field, model_validator
 
+from letta.constants import FUNCTION_RETURN_CHAR_LIMIT
 from letta.functions.functions import derive_openai_json_schema
 from letta.functions.helpers import (
     generate_composio_tool_wrapper,
@@ -41,6 +42,9 @@ class Tool(BaseTool):
     source_code: str = Field(..., description="The source code of the function.")
     json_schema: Optional[Dict] = Field(None, description="The JSON schema of the function.")
 
+    # tool configuration
+    return_char_limit: int = Field(FUNCTION_RETURN_CHAR_LIMIT, description="The maximum number of characters in the response.")
+
     # metadata fields
     created_by_id: Optional[str] = Field(None, description="The id of the user that made this Tool.")
     last_updated_by_id: Optional[str] = Field(None, description="The id of the user that made this Tool.")
@@ -91,6 +95,7 @@ class ToolCreate(LettaBase):
     json_schema: Optional[Dict] = Field(
         None, description="The JSON schema of the function (auto-generated from source_code if not provided)"
     )
+    return_char_limit: int = Field(FUNCTION_RETURN_CHAR_LIMIT, description="The maximum number of characters in the response.")
 
     @classmethod
     def from_composio(cls, action_name: str, api_key: Optional[str] = None) -> "ToolCreate":

letta/utils.py

@@ -28,7 +28,6 @@
     CLI_WARNING_PREFIX,
     CORE_MEMORY_HUMAN_CHAR_LIMIT,
     CORE_MEMORY_PERSONA_CHAR_LIMIT,
-    FUNCTION_RETURN_CHAR_LIMIT,
     LETTA_DIR,
     MAX_FILENAME_LENGTH,
     TOOL_CALL_ID_MAX_LEN,
@@ -906,8 +905,8 @@ def parse_json(string) -> dict:
         raise e
 
 
-def validate_function_response(function_response_string: any, strict: bool = False, truncate: bool = True) -> str:
-    """Check to make sure that a function used by Letta returned a valid response
+def validate_function_response(function_response_string: any, return_char_limit: int, strict: bool = False, truncate: bool = True) -> str:
+    """Check to make sure that a function used by Letta returned a valid response. Truncates to return_char_limit if necessary.
 
     Responses need to be strings (or None) that fall under a certain text count limit.
     """
@@ -943,11 +942,11 @@ def validate_function_response(function_response_string: any, strict: bool = Fal
 
     # Now check the length and make sure it doesn't go over the limit
     # TODO we should change this to a max token limit that's variable based on tokens remaining (or context-window)
-    if truncate and len(function_response_string) > FUNCTION_RETURN_CHAR_LIMIT:
+    if truncate and len(function_response_string) > return_char_limit:
         print(
-            f"{CLI_WARNING_PREFIX}function return was over limit ({len(function_response_string)} > {FUNCTION_RETURN_CHAR_LIMIT}) and was truncated"
+            f"{CLI_WARNING_PREFIX}function return was over limit ({len(function_response_string)} > {return_char_limit}) and was truncated"
         )
-        function_response_string = f"{function_response_string[:FUNCTION_RETURN_CHAR_LIMIT]}... [NOTE: function output was truncated since it exceeded the character limit ({len(function_response_string)} > {FUNCTION_RETURN_CHAR_LIMIT})]"
+        function_response_string = f"{function_response_string[:return_char_limit]}... [NOTE: function output was truncated since it exceeded the character limit ({len(function_response_string)} > {return_char_limit})]"
 
     return function_response_string