fix: cast dict values to str in _format_prompt

- Add str() casts for type safety
- These values are always strings when called from invoke

src/crewai/agent.py

@@ -1,7 +1,18 @@
 import shutil
 import subprocess
 import time
-from typing import Any, Callable, Dict, List, Literal, Optional, Sequence, Tuple, Type, Union
+from typing import (
+    Any,
+    Callable,
+    Dict,
+    List,
+    Literal,
+    Optional,
+    Sequence,
+    Tuple,
+    Type,
+    Union,
+)
 
 from pydantic import Field, InstanceOf, PrivateAttr, model_validator
 
@@ -76,6 +87,12 @@ class Agent(BaseAgent):
     """
 
     _times_executed: int = PrivateAttr(default=0)
+    agent_executor: Optional[CrewAgentExecutor] = Field(
+        default=None,
+        init=False,  # Not included in __init__ as it's created dynamically in create_agent_executor()
+        exclude=True,  # Excluded from serialization to avoid circular references
+        description="The agent executor instance for running tasks. Created dynamically when needed.",
+    )
     max_execution_time: Optional[int] = Field(
         default=None,
         description="Maximum execution time for an agent to execute a task",
@@ -162,7 +179,7 @@ class Agent(BaseAgent):
     )
     guardrail: Optional[Union[Callable[[Any], Tuple[bool, Any]], str]] = Field(
         default=None,
-        description="Function or string description of a guardrail to validate agent output"
+        description="Function or string description of a guardrail to validate agent output",
     )
     guardrail_max_retries: int = Field(
         default=3, description="Maximum number of retries when guardrail fails"
@@ -340,7 +357,6 @@ class Agent(BaseAgent):
             self.knowledge_config.model_dump() if self.knowledge_config else {}
         )
 
-
         if self.knowledge or (self.crew and self.crew.knowledge):
             crewai_event_bus.emit(
                 self,
@@ -531,6 +547,11 @@ class Agent(BaseAgent):
         Returns:
             The output of the agent.
         """
+        if not self.agent_executor:
+            raise ValueError(
+                "Agent executor not initialized. Call create_agent_executor() first."
+            )
+
         return self.agent_executor.invoke(
             {
                 "input": task_prompt,

src/crewai/agents/crew_agent_executor.py

@@ -96,7 +96,7 @@ class CrewAgentExecutor(CrewAgentExecutorMixin):
             )
         )
 
-    def invoke(self, inputs: Dict[str, str]) -> Dict[str, Any]:
+    def invoke(self, inputs: Dict[str, Union[str, bool, None]]) -> Dict[str, Any]:
         if "system" in self.prompt:
             system_prompt = self._format_prompt(self.prompt.get("system", ""), inputs)
             user_prompt = self._format_prompt(self.prompt.get("user", ""), inputs)
@@ -122,7 +122,6 @@ class CrewAgentExecutor(CrewAgentExecutorMixin):
             handle_unknown_error(self._printer, e)
             raise
 
-
         if self.ask_for_human_input:
             formatted_answer = self._handle_human_feedback(formatted_answer)
 
@@ -156,7 +155,7 @@ class CrewAgentExecutor(CrewAgentExecutorMixin):
                     messages=self.messages,
                     callbacks=self.callbacks,
                     printer=self._printer,
-                    from_task=self.task
+                    from_task=self.task,
                 )
                 formatted_answer = process_llm_response(answer, self.use_stop_words)
 
@@ -372,10 +371,13 @@ class CrewAgentExecutor(CrewAgentExecutorMixin):
         training_data[agent_id] = agent_training_data
         training_handler.save(training_data)
 
-    def _format_prompt(self, prompt: str, inputs: Dict[str, str]) -> str:
-        prompt = prompt.replace("{input}", inputs["input"])
-        prompt = prompt.replace("{tool_names}", inputs["tool_names"])
-        prompt = prompt.replace("{tools}", inputs["tools"])
+    def _format_prompt(
+        self, prompt: str, inputs: Dict[str, Union[str, bool, None]]
+    ) -> str:
+        # Cast to str to satisfy type checker - these are always strings when called
+        prompt = prompt.replace("{input}", str(inputs["input"]))
+        prompt = prompt.replace("{tool_names}", str(inputs["tool_names"]))
+        prompt = prompt.replace("{tools}", str(inputs["tools"]))
         return prompt
 
     def _handle_human_feedback(self, formatted_answer: AgentFinish) -> AgentFinish: