crewai/agents/executor.py

import time
from textwrap import dedent
from typing import Any, Dict, Iterator, List, Optional, Tuple, Union

from langchain.agents import AgentExecutor
from langchain.agents.agent import ExceptionTool
from langchain.agents.tools import InvalidTool
from langchain.callbacks.manager import CallbackManagerForChainRun
from langchain_core.agents import AgentAction, AgentFinish, AgentStep
from langchain_core.exceptions import OutputParserException
from langchain_core.pydantic_v1 import root_validator
from langchain_core.tools import BaseTool
from langchain_core.utils.input import get_color_mapping

from ..tools.cache_tools import CacheTools
from .cache.cache_hit import CacheHit


class CrewAgentExecutor(AgentExecutor):
    iterations: int = 0
    max_iterations: Optional[int] = 15
    force_answer_max_iterations: Optional[int] = None

    @root_validator()
    def set_force_answer_max_iterations(cls, values: Dict) -> Dict:
        values["force_answer_max_iterations"] = values["max_iterations"] - 2
        return values

    def _should_force_answer(self) -> bool:
        return True if self.iterations == self.force_answer_max_iterations else False

    def _force_answer(self, output: AgentAction):
        return AgentStep(
            action=output,
            observation=dedent(
                """\
            I've used too many tools for this task.
            I'm going to give you my absolute BEST Final answer now and
            not use any more tools."""
            ),
        )

    def _call(
        self,
        inputs: Dict[str, str],
        run_manager: Optional[CallbackManagerForChainRun] = None,
    ) -> Dict[str, Any]:
        """Run text through and get agent response."""
        # Construct a mapping of tool name to tool for easy lookup
        name_to_tool_map = {tool.name: tool for tool in self.tools}
        # We construct a mapping from each tool to a color, used for logging.
        color_mapping = get_color_mapping(
            [tool.name for tool in self.tools], excluded_colors=["green", "red"]
        )
        intermediate_steps: List[Tuple[AgentAction, str]] = []
        # Let's start tracking the number of iterations and time elapsed
        self.iterations = 0
        time_elapsed = 0.0
        start_time = time.time()
        # We now enter the agent loop (until it returns something).
        while self._should_continue(self.iterations, time_elapsed):
            next_step_output = self._take_next_step(
                name_to_tool_map,
                color_mapping,
                inputs,
                intermediate_steps,
                run_manager=run_manager,
            )
            if isinstance(next_step_output, AgentFinish):
                return self._return(
                    next_step_output, intermediate_steps, run_manager=run_manager
                )

            intermediate_steps.extend(next_step_output)
            if len(next_step_output) == 1:
                next_step_action = next_step_output[0]
                # See if tool should return directly
                tool_return = self._get_tool_return(next_step_action)
                if tool_return is not None:
                    return self._return(
                        tool_return, intermediate_steps, run_manager=run_manager
                    )
            self.iterations += 1
            time_elapsed = time.time() - start_time
        output = self.agent.return_stopped_response(
            self.early_stopping_method, intermediate_steps, **inputs
        )
        return self._return(output, intermediate_steps, run_manager=run_manager)

    def _iter_next_step(
        self,
        name_to_tool_map: Dict[str, BaseTool],
        color_mapping: Dict[str, str],
        inputs: Dict[str, str],
        intermediate_steps: List[Tuple[AgentAction, str]],
        run_manager: Optional[CallbackManagerForChainRun] = None,
    ) -> Iterator[Union[AgentFinish, AgentAction, AgentStep]]:
        """Take a single step in the thought-action-observation loop.

        Override this to take control of how the agent makes and acts on choices.
        """
        try:
            intermediate_steps = self._prepare_intermediate_steps(intermediate_steps)

            # Call the LLM to see what to do.
            output = self.agent.plan(
                intermediate_steps,
                callbacks=run_manager.get_child() if run_manager else None,
                **inputs,
            )
            if self._should_force_answer():
                if isinstance(output, AgentAction):
                    output = output
                else:
                    output = output.action
                yield self._force_answer(output)
                return

        except OutputParserException as e:
            if isinstance(self.handle_parsing_errors, bool):
                raise_error = not self.handle_parsing_errors
            else:
                raise_error = False
            if raise_error:
                raise ValueError(
                    "An output parsing error occurred. "
                    "In order to pass this error back to the agent and have it try "
                    "again, pass `handle_parsing_errors=True` to the AgentExecutor. "
                    f"This is the error: {str(e)}"
                )
            text = str(e)
            if isinstance(self.handle_parsing_errors, bool):
                if e.send_to_llm:
                    observation = str(e.observation)
                    text = str(e.llm_output)
                else:
                    observation = "Invalid or incomplete response"
            elif isinstance(self.handle_parsing_errors, str):
                observation = self.handle_parsing_errors
            elif callable(self.handle_parsing_errors):
                observation = self.handle_parsing_errors(e)
            else:
                raise ValueError("Got unexpected type of `handle_parsing_errors`")
            output = AgentAction("_Exception", observation, text)
            if run_manager:
                run_manager.on_agent_action(output, color="green")
            tool_run_kwargs = self.agent.tool_run_logging_kwargs()
            observation = ExceptionTool().run(
                output.tool_input,
                verbose=self.verbose,
                color=None,
                callbacks=run_manager.get_child() if run_manager else None,
                **tool_run_kwargs,
            )

            if self._should_force_answer():
                yield self._force_answer(output)
                return

            yield AgentStep(action=output, observation=observation)
            return

        # If the tool chosen is the finishing tool, then we end and return.
        if isinstance(output, AgentFinish):
            yield output
            return

        # Override tool usage to use CacheTools
        if isinstance(output, CacheHit):
            cache = output.cache
            action = output.action
            tool = CacheTools(cache_handler=cache).tool()
            output = action.copy()
            output.tool_input = f"tool:{action.tool}|input:{action.tool_input}"
            output.tool = tool.name
            name_to_tool_map[tool.name] = tool
            color_mapping[tool.name] = color_mapping[action.tool]

        actions: List[AgentAction]
        actions = [output] if isinstance(output, AgentAction) else output
        yield from actions
        for agent_action in actions:
            if run_manager:
                run_manager.on_agent_action(agent_action, color="green")
            # Otherwise we lookup the tool
            if agent_action.tool in name_to_tool_map:
                tool = name_to_tool_map[agent_action.tool]
                return_direct = tool.return_direct
                color = color_mapping[agent_action.tool]
                tool_run_kwargs = self.agent.tool_run_logging_kwargs()
                if return_direct:
                    tool_run_kwargs["llm_prefix"] = ""
                # We then call the tool on the tool input to get an observation
                observation = tool.run(
                    agent_action.tool_input,
                    verbose=self.verbose,
                    color=color,
                    callbacks=run_manager.get_child() if run_manager else None,
                    **tool_run_kwargs,
                )
            else:
                tool_run_kwargs = self.agent.tool_run_logging_kwargs()
                observation = InvalidTool().run(
                    {
                        "requested_tool_name": agent_action.tool,
                        "available_tool_names": list(name_to_tool_map.keys()),
                    },
                    verbose=self.verbose,
                    color=None,
                    callbacks=run_manager.get_child() if run_manager else None,
                    **tool_run_kwargs,
                )
            yield AgentStep(action=agent_action, observation=observation)