Implement A2A protocol support for recursive agent invocation

- Modified BaseAgentTool._execute to accept and pass tools parameter
- Updated DelegateWorkTool and AskQuestionTool to pass agent tools
- Modified AgentTools to inject tools into delegation tools
- Added test cases to verify recursive agent invocation works

Fixes #2900

Co-Authored-By: Joe Moura <joao@crewai.com>

src/crewai/tools/agent_tools/agent_tools.py

@@ -22,11 +22,21 @@ class AgentTools:
             i18n=self.i18n,
             description=self.i18n.tools("delegate_work").format(coworkers=coworkers),  # type: ignore
         )
+        delegate_tool._agent_tools = self._get_all_agent_tools()
 
         ask_tool = AskQuestionTool(
             agents=self.agents,
             i18n=self.i18n,
             description=self.i18n.tools("ask_question").format(coworkers=coworkers),  # type: ignore
         )
+        ask_tool._agent_tools = self._get_all_agent_tools()
 
         return [delegate_tool, ask_tool]
+        
+    def _get_all_agent_tools(self) -> list[BaseTool]:
+        """Get all tools from all agents for recursive invocation"""
+        all_tools = []
+        for agent in self.agents:
+            if agent.tools:
+                all_tools.extend(agent.tools)
+        return all_tools

src/crewai/tools/agent_tools/ask_question_tool.py

@@ -25,4 +25,5 @@ class AskQuestionTool(BaseAgentTool):
         **kwargs,
     ) -> str:
         coworker = self._get_coworker(coworker, **kwargs)
-        return self._execute(coworker, question, context)
+        tools = getattr(self, '_agent_tools', None) or kwargs.get('tools')
+        return self._execute(coworker, question, context, tools)

src/crewai/tools/agent_tools/base_agent_tools.py

@@ -1,5 +1,5 @@
 import logging
-from typing import Optional
+from typing import Any, List, Optional
 
 from pydantic import Field
 
@@ -50,7 +50,8 @@ class BaseAgentTool(BaseTool):
         self,
         agent_name: Optional[str],
         task: str,
-        context: Optional[str] = None
+        context: Optional[str] = None,
+        tools: Optional[List[Any]] = None
     ) -> str:
         """
         Execute delegation to an agent with case-insensitive and whitespace-tolerant matching.
@@ -59,6 +60,7 @@ class BaseAgentTool(BaseTool):
             agent_name: Name/role of the agent to delegate to (case-insensitive)
             task: The specific question or task to delegate
             context: Optional additional context for the task execution
+            tools: Optional tools to pass to the delegated agent for recursive invocation
 
         Returns:
             str: The execution result from the delegated agent or an error message
@@ -113,9 +115,10 @@ class BaseAgentTool(BaseTool):
                 agent=agent,
                 expected_output=agent.i18n.slice("manager_request"),
                 i18n=agent.i18n,
+                tools=tools,
             )
             logger.debug(f"Created task for agent '{self.sanitize_agent_name(agent.role)}': {task}")
-            return agent.execute_task(task_with_assigned_agent, context)
+            return agent.execute_task(task_with_assigned_agent, context, tools)
         except Exception as e:
             # Handle task creation or execution errors
             return self.i18n.errors("agent_tool_execution_error").format(

src/crewai/tools/agent_tools/delegate_work_tool.py

@@ -27,4 +27,5 @@ class DelegateWorkTool(BaseAgentTool):
         **kwargs,
     ) -> str:
         coworker = self._get_coworker(coworker, **kwargs)
-        return self._execute(coworker, task, context)
+        tools = getattr(self, '_agent_tools', None) or kwargs.get('tools')
+        return self._execute(coworker, task, context, tools)