Cannot call 'send' once a close message has been sent.

[abrar360]

Once the LLM hangs up a phone call, and closes the websocket connection. Pipecat still continues to try to send packets over it which causes issues:

[markbackman]

How are you shutting down your Pipeline?

You can either:

• push an EndTaskFrame upstream, which results in the source sending an EndFrame downstream to shut down processors (recommended)
• push an EndFrame from the PipelineTask

[abrar360]

Right now, I'm just providing a tool called hang_up_phone whose handler makes an API call to the phone provider to end the call. The transition handler then transitions to the end node (which is basically just a dummy node) which is probably pushing the end frame via the end_conversation post action. Based on what you're suggesting I might need to swap the order of that so that end_conversation action is called before making the API call to hang_up.

[markbackman]

@abrar360, sorry for the delay. Yes, switching the ordering makes sense. A user posted a good tip for this in Discord:

I'm using websockets with Twilio and the agent is reliably closing the websocket as part of the end_call node in a Pipecat Flow. I then just bind a function that terminates the twilio call to the on_client_disconnected event on the transport. The function sets status completed on the call via the API. Seems to work very well.

I would recommend going this route. That is:

• Use an end_conversation post_action
• In the on_client_disconnected handler, terminate the Twilio call

[abrar360]

No worries, thanks for getting back to me. For now, I was able to resolve the issue by just inserting a canned TTSSay response inside the hang_up_phone tool before the actual api call is made to hang up. I'm not sure exactly how this resolves it, but it seems to work fairly well so far and lead to predictable behavior.

The solution you mentioned does seem cleaner so I may switch to that later on if I face any additional issues.