# After hours answering service: voicemail, people, or an AI agent

> Compare after hours answering service options: voicemail, a human service, and an AI agent. Then set up after hours call answering with Hail.

- URL: https://hail.so/blog/after-hours-answering-service
- Type: Guide
- Tags: voice-agent, inbound, answering-service
- Published: 2026-10-28
- Reading time: 8 min

An after hours answering service picks up the calls your team cannot take at night, on weekends, and on holidays. You have four common choices: voicemail, a human answering service, an AI agent, or an AI agent that passes urgent calls to a person. The right one depends on how many calls you get, how many are urgent, and who must act on them.

This guide compares the four options. Then it shows how to set up the last one through your AI assistant. You use [Hail MCP](https://hail.so/mcp) for the setup.

## After hours answering service options compared

| | Voicemail | Human answering service | AI agent | AI agent with handover |
| --- | --- | --- | --- | --- |
| Hours covered | All hours | The hours in your plan | All hours | All hours |
| Cost model | Usually part of your phone plan | Monthly plan, often per minute or per call | Per minute of talk time | Per minute of talk time |
| Urgent calls | Wait until someone checks messages | The operator follows your script and calls your on-call person | The agent can take details and send them to you, but it cannot act | The agent passes the live call to an on-call person you pick |
| Setup | Record a greeting | Write a script with the service, then forward your line | Write instructions, then route a number | Instructions, a number, and a list of people to call |
| What the caller gets | A beep | A person who reads your script | A spoken answer at once | A spoken answer, and a person when it matters |

Prices for human services change by provider and plan, so compare quotes with the same call volume. For the AI options, estimate your minutes with the [voice agent cost calculator](https://hail.so/tools/voice-agent-cost-calculator) and read the [Hail rate card](https://hail.so/pricing).

## After hours call answering: what callers need

Most calls after hours ask for one of a few things. Write them down before you choose a tool:

- **Information.** Opening hours, an address, a price list. An agent can answer these from its instructions.
- **A booking or a callback.** The caller wants a time. The agent collects a name, a number, and a preferred time. Your team confirms the next day.
- **An urgent problem.** A burst pipe, a locked-out tenant, a patient in pain. A person must decide. These calls need a handover.
- **Sales.** A new customer who calls a competitor if nobody answers.

If almost every call is urgent, a person must stay on call. An AI agent then works as the first answer and the router, not as a replacement.

## After hours call center services vs an AI agent

An after hours call center gives you trained people who follow a script. They handle surprises well. They can also be slow to update: a change to your script often goes through their staff.

An AI agent follows the instructions you save. Ask your AI assistant to change them through Hail MCP. The next call uses the new instructions. It sounds the same at 3 a.m. as at noon. It can also be wrong: it can misunderstand a name or a time. Test it with real calls before you trust it, and keep a person in the loop for urgent cases.

Many teams mix the two: the agent answers every call, solves the simple ones, and hands urgent calls to a person.

## After hours virtual receptionist with Hail

On Hail, an agent is a saved setup: instructions, a greeting, a voice, tools, and limits. A number sends its incoming calls to one agent. These steps build an after hours virtual receptionist that hands urgent calls to your on-call person.

### 1. Connect Hail to your AI assistant

Open the [Hail MCP setup guide](https://hail.so/mcp) and choose your assistant. Follow its steps to connect your Hail account.

### 2. Ask your assistant to set up the phone agent

Replace the parts in capitals. Paste this request into your AI assistant.
Include the [phone agent instructions below](#after-hours-phone-answering-service-prompt) in the same message.

**Request for your AI assistant:**

```prompt
Create an after-hours phone agent for COMPANY NAME using Hail.
Use the phone agent instructions I include below.
Transfer urgent calls to CONTACT NAME.
Ask which existing Hail number to use.
Ask me for any missing business details or contact phone numbers.
Tell me which number and contact you will use before you connect the agent.
```

Your assistant can save the agent, add the transfer contact, and connect the number through Hail MCP.
Hail tells callers they are speaking to AI by default.

### 3. Answer only after hours

The agent answers whenever someone calls its Hail number. This setup does not set office hours for your main line.

Use your phone provider's call forwarding to send calls to the Hail number at closing time.
Or publish the Hail number as your after hours line.

## After hours phone answering service prompt

These instructions tell the phone agent how to handle callers. Replace the parts in capitals.
Send them with the setup request above in the same message to your AI assistant.

**Instructions for the phone agent:**

```prompt
You answer the phone for COMPANY NAME when the office is closed. Office hours are HOURS.

Your jobs, in this order:
1. Find out why the person is calling. Ask one question at a time.
2. If it is an emergency (EMERGENCY LIST), hand the call to the on-call person at once.
3. If they want a booking or a callback, collect their name, phone number, address, and a good time. Read the details back to them.
4. If they ask about hours, location, or services, answer from these facts: FACTS.

Rules:
- Never promise a time, a price, or a visit. Say that the team will confirm.
- If you do not know an answer, say so and offer a callback.
- If the caller is upset, stay calm and offer to pass the call to a person.
- End the call politely when the caller has nothing more to ask.
```

For a guided version, build the prompt with the [voice agent prompt builder](https://hail.so/tools/voice-agent-prompt-builder).

## Before you go live

- [ ] Call the number yourself at night and try each type of request.
- [ ] Say an emergency and check that the on-call person's phone rings.
- [ ] Let the on-call phone ring out, and check that the agent offers to take a message.
- [ ] If you use webhooks, check that they arrive at your server.
- [ ] Read your local rules about call recording and AI disclosure.

To learn how agents work for both incoming and outgoing calls, read [what an AI phone agent is](https://hail.so/blog/ai-phone-agent). To call customers back the next morning with the same agent, read [AI outbound calls](https://hail.so/blog/ai-outbound-calls).

## Set up with the API (optional)

You can also build this setup in your own code. The API steps below replace the MCP setup above.

### 1. Save the agent

Keep your API key on your server, in `HAIL_API_KEY`.
Use the phone agent instructions above as `system_prompt`.

```bash
curl -X POST https://api.hail.so/v1/agents \
  -H "Authorization: Bearer $HAIL_API_KEY" \
  -H 'Content-Type: application/json' \
  --data '{
    "name": "After hours desk",
    "system_prompt": "PASTE THE PHONE AGENT INSTRUCTIONS ABOVE",
    "first_message": "Thanks for calling Acme Plumbing. Our office is closed, but I can help. What do you need?",
    "voice_config": {"language": "en"}
  }'
```

Save the `id` from the response. Hail adds an AI line by default. With this `first_message`, the agent says its first sentence, then "I'm an AI assistant for" your organization, then the rest. Callers know at once that they talk to an AI.

### 2. Add the people for urgent calls

`handover_contacts` lists up to 10 people. Each has a `note` that tells the agent when to call them. Use the id that `GET /v1/contacts` shows: a contact's uuid, or `member:<user id>` for a team member.

```bash
curl -X PATCH "https://api.hail.so/v1/agents/$AGENT_ID" \
  -H "Authorization: Bearer $HAIL_API_KEY" \
  -H 'Content-Type: application/json' \
  --data '{
    "handover_contacts": [
      {"contact_id": "'"$ON_CALL_CONTACT_ID"'", "note": "Emergencies: active leaks, no water, no heat"}
    ]
  }'
```

The on-call person has 30 seconds to answer. If they do not, the agent comes back and offers to take a message. When they answer, the agent tells them who is calling and why, then goes silent.

### 3. Route your number to the agent

```bash
curl -X PATCH "https://api.hail.so/v1/numbers/$NUMBER_ID" \
  -H "Authorization: Bearer $HAIL_API_KEY" \
  -H 'Content-Type: application/json' \
  --data '{"voice_agent_id": "'"$AGENT_ID"'"}'
```

Hail registers the number for inbound calls. Each answered minute costs the same as an outbound minute.

### 4. Get a list of overnight calls
For an optional morning email, send your team the caller's number and whether the call was answered or transferred.
This list does not include what the caller said. It needs a server and a daily schedule that you set up.

Your server can build this list from call webhooks. Subscribe with `POST /v1/webhooks`.
Hail sends `call.received` when a call comes in, then `call.answered` and `call.completed`.
If the agent hands a call to a person, you also get `call.transferred`.
Each event includes the call `id`, `from`, `to`, and `status`.
Your server must collect these events and send the morning email through the [email API](https://hail.so/email).