How a call ends

A call ends in one of three ways:

• the other party hangs up;
• the AI agent ends it with the end_call tool;
• Skysay ends it under one of its safety rules.

This page covers the second, and the one safety rule that watches for a conversation that has gone quiet. The complete set of reasons a call can end with is in Post-call results.

The agent ends the call with end_call

When the conversation is over, the agent calls the built-in end_call tool. Skysay then plays its goodbye to the end and hangs up. The call reports ended_reason agent_completed.

Where the goodbye comes from depends on the conversation engine:

• Standard (speech-to-text, model, text-to-speech): the agent passes its goodbye as the tool's message, and Skysay speaks it in the agent's voice. The agent does not say a separate goodbye first.
• GPT-Live 1 and Gemini Live: these engines speak for themselves, so there is no separate voice for Skysay to speak a text line with. The agent says its own short goodbye and then calls end_call in the same turn. Skysay lets that goodbye finish playing, then hangs up. The tool's message is not spoken on these engines, and it is not recorded as something the caller heard.

Either way, the wait for the goodbye is bounded. If it does not finish within about 15 seconds, the call is ended anyway.

The standing call-ending instruction

Every agent that has end_call enabled receives the same instruction from Skysay, added after your own prompt on every call:

To end the call, invoke end_call. (One sentence on where the goodbye goes, as described above for your engine.) After your goodbye the conversation is over: if the caller speaks again, answer at most once, briefly, then invoke end_call. If you are calling a specific person and whoever answers says they are not that person, apologise once, share nothing about the matter, and invoke end_call. Never say goodbye and then keep the conversation going. Apart from the wrong person answering, invoke end_call only when the caller has said goodbye or has confirmed they need nothing else; never end it because you cannot help with their request, and never while they are still telling you something.

It is written in English for every language. The agent follows it in whatever language the conversation is in, and it never becomes part of what the caller hears.

It cannot be switched off for an agent that has end_call. Turning end_call off is how you opt out: an agent without the tool receives none of this instruction. The instruction stays on for an agent with end_call because it is meant to prevent four failures that show up in real calls:

• an agent that said goodbye and then kept the line open for minutes;
• an agent that kept pursuing someone who had said they were the wrong person;
• an agent that answered every follow-up question with another goodbye;
• an agent that hung up on a caller who was still explaining their problem in short sentences, often because it had decided it could not help.

So the agent is instructed to end a call only when one of these happens:

• the caller says goodbye;
• the caller confirms they need nothing else;
• the person who answers says they are not the person you are calling.

It is also instructed, when it cannot help with a request, to say so and stay on the line. This is an instruction to the model, not a guarantee: the model decides when to invoke end_call, and it can still end a call earlier than these rules allow, including while the caller is still talking. Whatever the agent does, the call also ends when the caller hangs up or when it reaches its maximum length.

The wrong-person rule matters most when you call people about their own accounts. Your own prompt still decides everything else about the conversation.

The instruction also reaches every language profile a language-following agent can switch to. On GPT-Live 1 it also reaches the backend model that decides when to call tools.

When both sides go quiet

Rolling out. This rule is currently in observation: on every call, Skysay records when it would have checked in and when it would have ended the call, and it does not yet do either. Calls behave as they did before, and caller_unresponsive does not appear yet. It will be switched on once the observations show it never would have ended a call wrongly. This page will say so when it is on.

Sometimes the agent speaks, and then nothing more comes from either side. The caller may have put the phone down, walked away, or lost the connection in a way the network never reported. Without this rule, such a line stayed open until the call reached its maximum length.

• After 30 seconds of mutual silence, the agent checks in once. It asks one short question, in the language of the conversation, whether the caller is still there. On a Standard agent in English it is "Are you still there?". On GPT-Live 1 and Gemini Live the agent's own model says it.
• If the caller answers, the conversation simply continues. One word is enough, and "yes" counts. A later silence gets a new check-in.
• If nobody answers within 15 seconds after the check-in has played, the agent says a short goodbye and the call ends. It reports ended_reason caller_unresponsive.

The clock only runs while the agent had the last word. If the caller spoke last, the agent owes them a reply, and a different safety rule watches that case. See When the conversation engine is lost.

The clock also does not run in these cases:

• while one of the agent's tools is running;
• while a scripted workflow step is on its way;
• while a language switch is being applied;
• after a transfer to a human has connected the caller to your team;
• while the call is already ending.

Line noise without words pauses the clock for at most 20 seconds, so a noisy line cannot hold a call open for ever. Background sound on its own never counts as the caller answering.

At most three check-ins are made on one call. After that, a silence still ends the call only after the same 45 seconds, just without asking first.

Agents that run a workflow do not get the check-in. The caller's answer to it ("yes, I'm here") would otherwise reach the workflow's current step as the answer to that step's own question. For these agents, a silence of 45 seconds ends the call politely with caller_unresponsive.

Why 30 and 15 seconds

The values come from real calls. Across more than 2,000 silences in the middle of real conversations on Skysay:

• none lasted 45 seconds;
• one lasted 30 seconds, and the caller spoke again at 34 seconds. They would have heard one harmless "are you still there?".

Silent tails that ran on for minutes, or for a quarter of an hour, would each have ended about 45 seconds into the silence.

These values are the same for every agent and cannot be changed per agent.

Where you see it

caller_unresponsive appears wherever ended_reason does:

• on GET /v1/calls/{call_id} and in GET /v1/calls list results;
• in the terminal call.completed webhook;
• in the campaign contact export, as the call's ending.

The workspace Calls page does not show a call's ending reason yet, for any reason. Until it does, read it from the API or the webhook.

A campaign contact whose call ended this way is treated like any other completed call. It is not retried automatically.

Retrying a contact whose call ended this way is your decision, not the platform's. The precise reason is there for your integration or campaign settings to act on.