nanobot/agent/subagent.py

@@ -16,6 +16,7 @@ from nanobot.agent.tools.filesystem import ReadFileTool, WriteFileTool, EditFile
 from nanobot.agent.tools.shell import ExecTool
 from nanobot.agent.tools.web import WebSearchTool, WebFetchTool
 from nanobot.agent.tools.spawn import SpawnTool
+from nanobot.agent.tools.subagent_message import SubagentMessageTool
 from nanobot.agent.tools.wait import WaitForSubagentsTool
 
 
@@ -121,6 +122,17 @@ class SubagentManager:
             ))
             tools.register(WebSearchTool(api_key=self.brave_api_key))
             tools.register(WebFetchTool())
+
+            # Message tool for communicating with user (via main agent)
+            message_tool = SubagentMessageTool(
+                bus=self.bus,
+                origin_channel=origin["channel"],
+                origin_chat_id=origin["chat_id"],
+                origin_metadata=origin.get("metadata"),
+            )
+            tools.register(message_tool)
+
+            # Spawn tool for creating child subagents
             spawn_tool = SpawnTool(manager=self)
             spawn_tool.set_context("subagent", origin["chat_id"], origin.get("metadata"))
             tools.register(spawn_tool)
@@ -252,11 +264,12 @@ You are a subagent spawned by the main agent to complete a specific task.
 - Read and write files in the workspace
 - Execute shell commands
 - Search the web and fetch web pages
+- Send messages to the user (via the message tool)
+- Spawn child subagents for parallel tasks
 - Complete the task thoroughly
 
 ## What You Cannot Do
-- Send messages directly to users (no message tool available)
-- Access the main agent's conversation history
+- Access the main agent's conversation history directly
 
 ## Workspace
 Your workspace is at: {self.workspace}

nanobot/agent/tools/subagent_message.py

@@ -0,0 +1,72 @@
+"""Message tool for subagents to communicate with the main agent."""
+
+from typing import Any, TYPE_CHECKING
+
+from nanobot.agent.tools.base import Tool
+from nanobot.bus.events import InboundMessage
+
+if TYPE_CHECKING:
+    from nanobot.bus.queue import MessageBus
+
+
+class SubagentMessageTool(Tool):
+    """
+    Tool for subagents to send messages to the main agent.
+
+    Messages are sent via the bus and preserve metadata (e.g. suppress_output)
+    from the originating message that spawned the subagent.
+    """
+
+    def __init__(
+        self,
+        bus: "MessageBus",
+        origin_channel: str,
+        origin_chat_id: str,
+        origin_metadata: dict[str, Any] | None = None,
+    ):
+        self._bus = bus
+        self._origin_channel = origin_channel
+        self._origin_chat_id = origin_chat_id
+        self._origin_metadata = origin_metadata or {}
+
+    @property
+    def name(self) -> str:
+        return "message"
+
+    @property
+    def description(self) -> str:
+        return (
+            "Send a message to the user through the main agent. "
+            "Use this to communicate findings, ask questions, or provide updates. "
+            "Messages will be delivered through the same channel that spawned this subagent."
+        )
+
+    @property
+    def parameters(self) -> dict[str, Any]:
+        return {
+            "type": "object",
+            "properties": {
+                "content": {
+                    "type": "string",
+                    "description": "The message content to send to the user"
+                },
+            },
+            "required": ["content"]
+        }
+
+    async def execute(self, content: str, **kwargs: Any) -> str:
+        """Send a message to the main agent via the bus."""
+        # Create InboundMessage to trigger main agent
+        msg = InboundMessage(
+            channel="system",
+            sender_id="subagent",
+            chat_id=f"{self._origin_channel}:{self._origin_chat_id}",
+            content=f"[Subagent message]\n\n{content}",
+            metadata=self._origin_metadata,
+        )
+
+        try:
+            await self._bus.publish_inbound(msg)
+            return "Message sent to user"
+        except Exception as e:
+            return f"Error sending message: {str(e)}"