Fix(multi-agent #20): inherit model from parent/caller in swarm, agent graph, workflow, use_llm and think tools

.gitignore

@@ -13,3 +13,4 @@ errors/
 repl_state/
 venv/
 *.egg-info
+.idea

src/strands_tools/agent_graph.py

@@ -513,6 +513,7 @@ def agent_graph(tool: ToolUse, **kwargs: Any) -> ToolResult:
     inference_config = kwargs.get("inference_config")
     messages = kwargs.get("messages")
     tool_config = kwargs.get("tool_config")
+    agent = kwargs.get("agent")
 
     try:
         # Create tool context
@@ -522,6 +523,7 @@ def agent_graph(tool: ToolUse, **kwargs: Any) -> ToolResult:
             "inference_config": inference_config,
             "messages": messages,
             "tool_config": tool_config,
+            "agent": agent,
         }
 
         # Get manager instance thread-safely

src/strands_tools/memory.py

@@ -583,7 +583,7 @@ def memory(
         next_token: Token for pagination in 'list' or 'retrieve' action (optional).
         query: The search query for semantic search (required for 'retrieve' action).
         min_score: Minimum relevance score threshold (0.0-1.0) for 'retrieve' action. Default is 0.4.
-        region_name: Optional AWS region name. If not provided, will use the AWS_REGION env variable. 
+        region_name: Optional AWS region name. If not provided, will use the AWS_REGION env variable.
             If AWS_REGION is not specified, it will default to us-west-2.
 
     Returns:

src/strands_tools/swarm.py

@@ -586,12 +586,14 @@ def swarm(tool: ToolUse, **kwargs: Any) -> ToolResult:
         inference_config = kwargs.get("inference_config")
         messages = kwargs.get("messages")
         tool_config = kwargs.get("tool_config")
+        agent = kwargs.get("agent")
         # Create tool context
         tool_context = {
             "system_prompt": system_prompt,
             "inference_config": inference_config,
             "messages": messages,
             "tool_config": tool_config,
+            "agent": agent,
         }
         if "callback_handler" in kwargs:
             tool_context["callback_handler"] = kwargs["callback_handler"]

src/strands_tools/think.py

@@ -95,13 +95,21 @@ def process_cycle(
         # Get tools from parent agent if available
         tools = []
         trace_attributes = {}
+        extra_kwargs = {}
         parent_agent = kwargs.get("agent")
         if parent_agent:
             tools = list(parent_agent.tool_registry.registry.values())
             trace_attributes = parent_agent.trace_attributes
+            extra_kwargs["model"] = parent_agent.model
 
         # Initialize the new Agent with provided parameters
-        agent = Agent(messages=[], tools=tools, system_prompt=custom_system_prompt, trace_attributes=trace_attributes)
+        agent = Agent(
+            messages=[],
+            tools=tools,
+            system_prompt=custom_system_prompt,
+            trace_attributes=trace_attributes,
+            **extra_kwargs,
+        )
 
         # Run the agent with the provided prompt
         result = agent(prompt)

src/strands_tools/use_llm.py

@@ -126,6 +126,7 @@ def use_llm(tool: ToolUse, **kwargs: Any) -> ToolResult:
         tools = list(parent_agent.tool_registry.registry.values())
         trace_attributes = parent_agent.trace_attributes
         extra_kwargs["callback_handler"] = parent_agent.callback_handler
+        extra_kwargs["model"] = parent_agent.model
     if "callback_handler" in kwargs:
         extra_kwargs["callback_handler"] = kwargs["callback_handler"]
 

src/strands_tools/workflow.py

@@ -212,6 +212,13 @@ def __new__(cls, tool_context: Dict[str, Any]):
     def __init__(self, tool_context: Dict[str, Any]):
         if not hasattr(self, "initialized"):
             # Initialize core attributes
+            extra_kwargs = {}
+            parent_agent = tool_context.get("agent", None)
+            if parent_agent:
+                extra_kwargs["tools"] = list(parent_agent.tool_registry.registry.values())
+                extra_kwargs["trace_attributes"] = parent_agent.trace_attributes
+                extra_kwargs["callback_handler"] = parent_agent.callback_handler
+                extra_kwargs["model"] = parent_agent.model
             self.system_prompt = tool_context["system_prompt"]
             self.inference_config = tool_context["inference_config"]
             self.messages = tool_context["messages"]
@@ -221,7 +228,7 @@ def __init__(self, tool_context: Dict[str, Any]):
             self.task_executor = TaskExecutor()
 
             # Initialize base agent for task execution
-            self.base_agent = Agent(system_prompt=self.system_prompt)
+            self.base_agent = Agent(system_prompt=self.system_prompt, **extra_kwargs)
 
             # Start file watching if not already started
             if not self._observer:
@@ -748,6 +755,7 @@ def workflow(tool: ToolUse, **kwargs: Any) -> ToolResult:
     inference_config = kwargs.get("inference_config")
     messages = kwargs.get("messages")
     tool_config = kwargs.get("tool_config")
+    agent = kwargs.get("agent")
 
     try:
         tool_use_id = tool.get("toolUseId", str(uuid.uuid4()))
@@ -761,6 +769,7 @@ def workflow(tool: ToolUse, **kwargs: Any) -> ToolResult:
                 "inference_config": inference_config,
                 "messages": messages,
                 "tool_config": tool_config,
+                "agent": agent,
             }
         )