Better agent execution error handling (#54)

A few quality of life improvements around cache handling and repeated tool usage

crewai/agents/__init__.py

@@ -1,4 +1,4 @@
-from .cache_handler import CacheHandler
+from .cache.cache_handler import CacheHandler
 from .executor import CrewAgentExecutor
 from .output_parser import CrewAgentOutputParser
 from .tools_handler import ToolsHandler

crewai/agents/cache/__init__.py

@@ -0,0 +1,2 @@
+from .cache_handler import CacheHandler
+from .cache_hit import CacheHit

crewai/agents/exceptions.py

@@ -0,0 +1,20 @@
+from langchain_core.exceptions import OutputParserException
+
+
+class TaskRepeatedUsageException(OutputParserException):
+    """Exception raised when a task is used twice in a roll."""
+
+    error: str = "TaskRepeatedUsageException"
+    message: str = "\nI just used the {tool} tool with input {tool_input}. So I already know the result of that.\n"
+
+    def __init__(self, tool: str, tool_input: str):
+        self.tool = tool
+        self.tool_input = tool_input
+        self.message = self.message.format(tool=tool, tool_input=tool_input)
+
+        super().__init__(
+            error=self.error, observation=self.message, send_to_llm=True, llm_output=""
+        )
+
+    def __str__(self):
+        return self.message

crewai/agents/executor.py

@@ -9,7 +9,7 @@ from langchain_core.exceptions import OutputParserException
 from langchain_core.tools import BaseTool
 
 from ..tools.cache_tools import CacheTools
-from .cache_hit import CacheHit
+from .cache.cache_hit import CacheHit
 
 
 class CrewAgentExecutor(AgentExecutor):

crewai/agents/output_parser.py

@@ -3,10 +3,9 @@ from typing import Union
 
 from langchain.agents.output_parsers import ReActSingleInputOutputParser
 from langchain_core.agents import AgentAction, AgentFinish
-from langchain_core.exceptions import OutputParserException
 
-from .cache_handler import CacheHandler
-from .cache_hit import CacheHit
+from .cache import CacheHandler, CacheHit
+from .exceptions import TaskRepeatedUsageException
 from .tools_handler import ToolsHandler
 
 FINAL_ANSWER_ACTION = "Final Answer:"
@@ -67,9 +66,7 @@ class CrewAgentOutputParser(ReActSingleInputOutputParser):
                     "input": tool_input,
                 }
                 if usage == last_tool_usage:
-                    raise OutputParserException(
-                        f"""\nI just used the {action} tool with input {tool_input}. So I already know the result of that."""
-                    )
+                    raise TaskRepeatedUsageException(tool=action, tool_input=tool_input)
 
             result = self.cache.read(action, tool_input)
             if result:

crewai/agents/tools_handler.py

@@ -3,7 +3,7 @@ from typing import Any, Dict
 from langchain.callbacks.base import BaseCallbackHandler
 
 from ..tools.cache_tools import CacheTools
-from .cache_handler import CacheHandler
+from .cache.cache_handler import CacheHandler
 
 
 class ToolsHandler(BaseCallbackHandler):