Everyone talks about AI voice agents. And voice is powerful. But here's something I've learned from watching teams build on AgentLine: SMS does a lot of the heavy lifting.
Think about it. Not everyone wants to pick up a phone. But almost everyone reads their texts. SMS is low-pressure, asynchronous, and it creates a written record of every interaction. For a lot of use cases, it's actually the better channel.
Here's how SMS works with AgentLine, what you can build with it, and some practical tips from teams already doing it.
How SMS Works on AgentLine
When you provision a phone number on AgentLine, it handles both voice calls and SMS. You don't need a separate number for texting.
Inbound SMS works like this: someone texts your agent's number, AgentLine receives it, and if you've configured your agent to check for messages, your AI agent can read and respond.
The message payload includes the sender's number, the message body, and a timestamp. Your agent sees it as text and can respond accordingly.
What You Can Build with SMS
Here are the SMS workflows teams are running on AgentLine right now:
Appointment confirmations: A patient texts "confirm" and your agent confirms their appointment in the scheduling system. No phone call needed.
Order status checks: A customer texts their order number and your agent looks up the status, replies with an ETA. This is one of the most common use cases we see in ecommerce.
Two-factor authentication: Your agent sends a verification code via SMS when someone logs in. Simple, reliable, no separate SMS provider needed.
Follow-up sequences: After a voice call, your agent sends a text with a summary or next steps. "Thanks for the call! Here's a link to schedule a demo: [link]"
Alerts and notifications: When a server goes down or a payment fails, your agent texts the right person. Voice calls are great for urgent things, but a text is often enough and less disruptive.
The Voice + SMS Combo
Where SMS really shines is when it works alongside voice calls. A common pattern we see:
- Your agent calls a lead to introduce your product
- The lead is busy, asks to be contacted later
- Your agent sends a text: "No worries! Text me when you have a few minutes and I'll call back. Or grab a time here: [calendar link]"
- The lead texts back, your agent calls, conversation happens
This is way better than playing phone tag. The SMS keeps the conversation alive without being pushy.
Things to Know About SMS on AgentLine
A few practical notes from the trenches:
Character limits: Standard SMS is 160 characters. Longer messages get split into multiple segments. Keep your texts short and to the point.
Delivery isn't guaranteed: SMS delivery depends on carriers. Most messages arrive within seconds, but some can be delayed. Build your workflow to handle this gracefully.
Sender ID: Your messages come from your AgentLine phone number. If you text someone repeatedly and they save your number, they'll recognize it. This is actually an advantage for building trust over time.
No MMS yet: As of now, AgentLine handles text SMS but not picture messages. If you need to send images, you'll want to use a link instead.
Building SMS Workflows
Setting up your AI agent to handle SMS is straightforward. Your agent checks for new messages and processes them like any other text input. Here's what a good SMS prompt looks like:
"You receive SMS messages from users. Keep responses brief, under 160 characters. If someone asks a complex question, say 'Let me call you to discuss this in more detail.' If someone asks about pricing, say 'Check out agentline.cloud/pricing or I can call you to walk through the options.'"
The key is brevity. SMS is not the place for long explanations. Get to the point.
Getting Started
If you already have an AgentLine account with a phone number, SMS is ready to go. Your number handles both voice and text from the start.
If you're new to AgentLine, sign up, provision a number, install the skill file, and you can start handling both calls and texts in the same workflow.
Start at agentline.cloud.