# SMS agents

> Create AI agents that reply to your leads' text messages, book meetings by text and follow up when a lead goes quiet.

- Section: Using the app (manual) › AI agent
- Web page: https://docs.biglysales.com/manual/sms-agents
- MCP (AI assistant) equivalent: [SMS agents](https://docs.biglysales.com/mcp/sms-agents.md)
- Video: placeholder — "Building and testing an SMS agent" (not yet recorded)

An **SMS agent** is the AI that texts with your leads. When a lead replies to one of your messages, the agent reads the conversation and writes the next reply. It also recognizes what the lead wants. For example, it stops texting someone who opts out, notes a wrong number, and asks for a call back when the lead says *"call me tomorrow at 3"*.

You can keep several agents, for example one per offer, and choose one as your **Default**.

## Before you start

- Have your company details and offer ready. They go into the agent's prompt.
- If you want the agent to book meetings, set up a calendar for the AI first. See [Calendar](https://docs.biglysales.com/manual/calendar.md) and [Availability](https://docs.biglysales.com/manual/availability.md).

## Create an agent

1. Go to **AI › SMS Agents**.
2. Click **Add Agent**. A new agent opens with a starter prompt already filled in.
3. Type a name at the top of the editor.
4. Fill in the **Role & Identity** tab (see below).
5. Fill in the **Prompt & Model** tab.
6. Click **Save**. New agents are saved as **Draft**.

> [Screenshot placeholder: SMS Agents list — AI › SMS Agents showing three agent cards, one with the blue Default badge and Active status, one Draft, plus the Add Agent card.]

### Role & Identity

| Field | What to enter |
|---|---|
| **Agent Name** | An internal name, such as *Sales Assistant*. Leads don't see it unless your prompt uses it. |
| **Agent Objective** | What this agent should achieve, such as *qualify the lead and book a call*. |
| **Opening Greeting** | The first message a new contact gets. Click a variable chip (FirstName, LastName, PhoneNumber, Email, Company, City, State, ZipCode) to insert it. You can use any contact attribute with the `{{FirstName}}` style. |
| **Follow-up Instruction** | How the agent should write a nudge when a lead stops replying. This is an instruction to the AI, not a message sent as-is, so placeholders don't work here. Used by [No reply followup](https://docs.biglysales.com/manual/no-reply-followup.md). |
| **Book meetings** | Lets the agent offer open times from your AI calendar and book a meeting when the lead picks one. |

### Prompt & Model

- **System Prompt**: the full instructions for the agent. The starter prompt has sections for identity, communication style, objectives, rules, hand-off and constraints. Replace every part in square brackets with your own details. The token count beside it is an estimate of the prompt's length.
- **AI Model**: pick the model the agent runs on. Models are grouped by provider.
- **Model Parameters**: **Temperature** (lower is more predictable, higher is more creative), **Max Output Tokens** (the longest reply it can write) and **Top P**. If you're unsure, leave the defaults.

> [Screenshot placeholder: Prompt & Model tab — The SMS agent editor on the Prompt & Model tab, with the System Prompt box, the AI Model cards grouped by provider with one selected, and the Temperature, Max Output Tokens and Top P sliders.]

## Test the agent

The **Test** tab appears once the agent has been saved.

1. Open the agent and click **Test**.
2. Type a message as if you were the lead and press Enter. The agent answers.
3. If the agent detects an intent other than a normal reply, the tag is shown under its message, for example **OPTOUT** or **CALLBACK_LATER**.
4. To test a reply partway through a conversation, click **Inject**, choose **User** or **Assistant**, type a message and click **Add**. Injected messages are marked *seeded*.
5. Click the clear icon to start over.

When **Book meetings** is on and the lead picks a time, the test shows **Meeting booked (test)**. This is simulated: no event is created and no message is sent.

> [Screenshot placeholder: Testing an agent — The Test tab with a short conversation: a user message asking to be called tomorrow afternoon and the agent's reply with the CALLBACK_LATER tag beneath it, plus the Inject button in the header.]

## Make the agent live

1. Click the **Draft** button in the editor header to switch it to **Active**.
2. Click **Set Default** to make it the agent that replies to your leads. Only an active agent can be the default, and only one agent can be the default at a time.
3. Click **Save**.

## What the agent can recognize

| Tag | What it means |
|---|---|
| REPLY | A normal reply that continues the conversation. |
| OPTOUT | The lead wants to stop receiving messages. |
| WRONG_NUMBER | The lead says it isn't their number. |
| NOT_INTERESTED | The lead isn't interested. |
| CALLBACK_NOW | The lead wants a call right away. |
| CALLBACK_LATER | The lead wants a call at a later time. Bigly schedules the AI call back. See [Scheduled callbacks](https://docs.biglysales.com/manual/scheduled-callbacks.md). |
| BOOK_MEETING | The lead picked one of the offered meeting times. Only when **Book meetings** is on. |

## Common questions

**I replied to a lead myself. Will the AI talk over me?** No. When someone on your team sends a text to a lead by hand, the AI stops replying to that lead for a while (24 hours by default) so you can take over.

**Can I delete an agent?** Yes. Click the delete icon on its card or in the editor, then **Delete**. This can't be undone.

**Why is Set Default greyed out?** The agent is still a **Draft**. Make it **Active** first.

## Related

- [No reply followup](https://docs.biglysales.com/manual/no-reply-followup.md)
- [Inbox](https://docs.biglysales.com/manual/inbox.md)
- [SMS campaigns](https://docs.biglysales.com/manual/sms-campaigns.md)
- [Calendar](https://docs.biglysales.com/manual/calendar.md)
- [SMS agents through the MCP](https://docs.biglysales.com/mcp/sms-agents.md)

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All documentation pages: https://docs.biglysales.com/llms.txt