Files
letta-server/letta/agents/base_agent.py

202 lines
8.4 KiB
Python

from abc import ABC, abstractmethod
from typing import Any, AsyncGenerator, List, Optional, Union
import openai
from letta.constants import DEFAULT_MAX_STEPS
from letta.helpers import ToolRulesSolver
from letta.helpers.datetime_helpers import get_utc_time
from letta.log import get_logger
from letta.prompts.prompt_generator import PromptGenerator
from letta.schemas.agent import AgentState
from letta.schemas.enums import MessageStreamStatus
from letta.schemas.letta_message import LegacyLettaMessage, LettaMessage
from letta.schemas.letta_message_content import TextContent
from letta.schemas.letta_response import LettaResponse
from letta.schemas.letta_stop_reason import LettaStopReason, StopReasonType
from letta.schemas.message import Message, MessageCreate, MessageUpdate
from letta.schemas.usage import LettaUsageStatistics
from letta.schemas.user import User
from letta.services.agent_manager import AgentManager
from letta.services.message_manager import MessageManager
from letta.services.passage_manager import PassageManager
from letta.utils import united_diff
logger = get_logger(__name__)
class BaseAgent(ABC):
"""
Abstract base class for AI agents, handling message management, tool execution,
and context tracking.
"""
def __init__(
self,
agent_id: str,
# TODO: Make required once client refactor hits
openai_client: Optional[openai.AsyncClient],
message_manager: MessageManager,
agent_manager: AgentManager,
actor: User,
):
self.agent_id = agent_id
self.openai_client = openai_client
self.message_manager = message_manager
self.agent_manager = agent_manager
# TODO: Pass this in
self.passage_manager = PassageManager()
self.actor = actor
self.logger = get_logger(agent_id)
@abstractmethod
async def step(
self, input_messages: List[MessageCreate], max_steps: int = DEFAULT_MAX_STEPS, run_id: Optional[str] = None
) -> LettaResponse:
"""
Main execution loop for the agent.
"""
raise NotImplementedError
@abstractmethod
async def step_stream(
self, input_messages: List[MessageCreate], max_steps: int = DEFAULT_MAX_STEPS
) -> AsyncGenerator[Union[LettaMessage, LegacyLettaMessage, MessageStreamStatus], None]:
"""
Main streaming execution loop for the agent.
"""
raise NotImplementedError
@staticmethod
def pre_process_input_message(input_messages: List[MessageCreate]) -> Any:
"""
Pre-process function to run on the input_message.
"""
def get_content(message: MessageCreate) -> str:
if isinstance(message.content, str):
return message.content
elif message.content and len(message.content) == 1 and isinstance(message.content[0], TextContent):
return message.content[0].text
else:
return ""
return [{"role": input_message.role.value, "content": get_content(input_message)} for input_message in input_messages]
async def _rebuild_memory_async(
self,
in_context_messages: List[Message],
agent_state: AgentState,
tool_rules_solver: Optional[ToolRulesSolver] = None,
num_messages: Optional[int] = None, # storing these calculations is specific to the voice agent
num_archival_memories: Optional[int] = None,
) -> List[Message]:
"""
Async version of function above. For now before breaking up components, changes should be made in both places.
"""
try:
# [DB Call] loading blocks (modifies: agent_state.memory.blocks)
agent_state = await self.agent_manager.refresh_memory_async(agent_state=agent_state, actor=self.actor)
tool_constraint_block = None
if tool_rules_solver is not None:
tool_constraint_block = tool_rules_solver.compile_tool_rule_prompts()
# compile archive tags if there's an attached archive
from letta.services.archive_manager import ArchiveManager
archive_manager = ArchiveManager()
archive = await archive_manager.get_default_archive_for_agent_async(
agent_id=agent_state.id,
actor=self.actor,
)
if archive:
archive_tags = await self.passage_manager.get_unique_tags_for_archive_async(
archive_id=archive.id,
actor=self.actor,
)
else:
archive_tags = None
# TODO: This is a pretty brittle pattern established all over our code, need to get rid of this
curr_system_message = in_context_messages[0]
curr_system_message_text = curr_system_message.content[0].text
# extract the dynamic section that includes memory blocks, tool rules, and directories
# this avoids timestamp comparison issues
def extract_dynamic_section(text):
start_marker = "</base_instructions>"
end_marker = "<memory_metadata>"
start_idx = text.find(start_marker)
end_idx = text.find(end_marker)
if start_idx != -1 and end_idx != -1:
return text[start_idx:end_idx]
return text # fallback to full text if markers not found
curr_dynamic_section = extract_dynamic_section(curr_system_message_text)
# generate just the memory string with current state for comparison
curr_memory_str = agent_state.memory.compile(
tool_usage_rules=tool_constraint_block,
sources=agent_state.sources,
max_files_open=agent_state.max_files_open,
llm_config=agent_state.llm_config,
)
new_dynamic_section = extract_dynamic_section(curr_memory_str)
# compare just the dynamic sections (memory blocks, tool rules, directories)
if curr_dynamic_section == new_dynamic_section:
logger.debug(
f"Memory and sources haven't changed for agent id={agent_state.id} and actor=({self.actor.id}, {self.actor.name}), skipping system prompt rebuild"
)
return in_context_messages
memory_edit_timestamp = get_utc_time()
# size of messages and archival memories
if num_messages is None:
num_messages = await self.message_manager.size_async(actor=self.actor, agent_id=agent_state.id)
if num_archival_memories is None:
num_archival_memories = await self.passage_manager.agent_passage_size_async(actor=self.actor, agent_id=agent_state.id)
new_system_message_str = PromptGenerator.get_system_message_from_compiled_memory(
system_prompt=agent_state.system,
memory_with_sources=curr_memory_str,
in_context_memory_last_edit=memory_edit_timestamp,
timezone=agent_state.timezone,
previous_message_count=num_messages - len(in_context_messages),
archival_memory_size=num_archival_memories,
archive_tags=archive_tags,
)
diff = united_diff(curr_system_message_text, new_system_message_str)
if len(diff) > 0:
logger.debug(f"Rebuilding system with new memory...\nDiff:\n{diff}")
# [DB Call] Update Messages
new_system_message = await self.message_manager.update_message_by_id_async(
curr_system_message.id,
message_update=MessageUpdate(content=new_system_message_str),
actor=self.actor,
project_id=agent_state.project_id,
)
return [new_system_message] + in_context_messages[1:]
else:
return in_context_messages
except:
logger.exception(f"Failed to rebuild memory for agent id={agent_state.id} and actor=({self.actor.id}, {self.actor.name})")
raise
def get_finish_chunks_for_stream(self, usage: LettaUsageStatistics, stop_reason: Optional[LettaStopReason] = None):
if stop_reason is None:
stop_reason = LettaStopReason(stop_reason=StopReasonType.end_turn.value)
return [
stop_reason.model_dump_json(),
usage.model_dump_json(),
MessageStreamStatus.done.value,
]