Add remote-proxy-assistant example

Demonstrates the WebSocket proxy tasks: a local `main.py` voice
bot uses `WebSocketProxyClientTask` to forward bus messages
(including `BusFrameMessage`s) to a remote `assistant.py`
FastAPI server. Each incoming connection spawns a
`WebSocketProxyServerTask` plus an `LLMTask` assistant on a
per-session `PipelineRunner`.

examples/multi-task/remote-proxy-assistant/assistant.py

@@ -0,0 +1,118 @@
+#
+# Copyright (c) 2026, Daily
+#
+# SPDX-License-Identifier: BSD 2-Clause License
+#
+
+"""Remote assistant LLM server.
+
+Runs a FastAPI server that accepts WebSocket connections from a
+``main.py``-style client. Each connection spins up a
+`WebSocketProxyServerTask` bridging the socket to a local
+`PipelineRunner` and an `LLMTask` that handles the conversation.
+
+Usage::
+
+    python assistant.py
+    python assistant.py --port 9000
+
+Requirements:
+
+- OPENAI_API_KEY
+"""
+
+import argparse
+import os
+
+import uvicorn
+from dotenv import load_dotenv
+from fastapi import FastAPI, WebSocket
+from loguru import logger
+
+from pipecat.bus import BusFrameMessage
+from pipecat.pipeline.runner import PipelineRunner
+from pipecat.services.llm_service import FunctionCallParams
+from pipecat.services.openai.llm import OpenAILLMService
+from pipecat.tasks.llm import LLMTask, tool
+from pipecat.tasks.proxy.websocket import WebSocketProxyServerTask
+
+load_dotenv(override=True)
+
+app = FastAPI()
+
+
+class AcmeAssistant(LLMTask):
+    """Handles greetings, product questions, and conversation end."""
+
+    def __init__(self):
+        """Initialize the AcmeAssistant LLM task."""
+        llm = OpenAILLMService(
+            api_key=os.environ["OPENAI_API_KEY"],
+            settings=OpenAILLMService.Settings(
+                system_instruction=(
+                    "You are a friendly assistant for Acme Corp. You know about three "
+                    "products: Acme Rocket Boots (jet-powered boots, $299, run up to "
+                    "60 mph), Acme Invisible Paint (makes anything invisible for 24 hours, "
+                    "$49 per can), and Acme Tornado Kit (portable tornado generator, $199, "
+                    "batteries included). Greet the user, help them with product questions, "
+                    "and call end_conversation when the user says goodbye. "
+                    "Keep responses brief, this is a voice conversation."
+                ),
+            ),
+        )
+        super().__init__("assistant", llm=llm, bridged=())
+
+    @tool
+    async def end_conversation(self, params: FunctionCallParams, reason: str):
+        """End the conversation when the user says goodbye.
+
+        Args:
+            reason (str): Why the conversation is ending.
+        """
+        logger.info(f"Task '{self.name}': ending conversation ({reason})")
+        await self.end(
+            reason=reason,
+            messages=[{"role": "developer", "content": reason}],
+            result_callback=params.result_callback,
+        )
+
+
+@app.websocket("/ws")
+async def websocket_endpoint(websocket: WebSocket):
+    """Handle a WebSocket connection from the main bot's proxy."""
+    await websocket.accept()
+
+    runner = PipelineRunner(handle_sigint=False)
+
+    proxy = WebSocketProxyServerTask(
+        "gateway",
+        websocket=websocket,
+        task_name="assistant",
+        remote_task_name="acme",
+        forward_messages=(BusFrameMessage,),
+    )
+
+    @proxy.event_handler("on_client_connected")
+    async def on_client_connected(proxy, client):
+        logger.info("WebSocket client connected")
+
+    @proxy.event_handler("on_client_disconnected")
+    async def on_client_disconnected(proxy, client):
+        logger.info("WebSocket client disconnected")
+        await runner.cancel()
+
+    assistant = AcmeAssistant()
+
+    await runner.spawn(proxy)
+    logger.info("Assistant server ready, waiting for activation")
+    await runner.run(assistant)
+    logger.info("Assistant server session ended")
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(description="Remote assistant LLM server")
+    parser.add_argument("--host", default="0.0.0.0", help="Host to bind to")
+    parser.add_argument("--port", type=int, default=8765, help="Port to listen on")
+    args = parser.parse_args()
+
+    uvicorn.run(app, host=args.host, port=args.port)