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An SMS agent holds text conversations with your customers: it replies on its number, starts conversations, runs actions — including texting someone else — remembers the contact between conversations, hands the chat to a person when needed, and closes the session when it’s done.
Lumina SMS agent editor with the Settings rail on the left, the Agent Prompt document in the centre and the Atlas, Test and Summary tabs on the right; the header shows the Lumina badge, the Inbound pill and the Active toggle

The whole agent on one screen: settings, prompt and the right panel

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What Lumina is

Lumina is Dialtu’s SMS engine. Dialtu runs the whole conversation end to end — the prompt, the model turn, the tools and the history. The carrier only transports the message. The engine picker offers two engines — choose Lumina; everything in this section describes it, and the engine can’t be changed afterwards.

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What an SMS agent can do

Answer texts on a schedule

Weekly hours per agent, or the number’s default agent for everything else.

Start conversations

By hand from the inbox, on a schedule, or from a Salesflow sequence.

Run tools

API, End Chat, Handoff, Send SMS, Integration and Calendar.

Hand to a person

A live inbox where your team takes over — and hands back to the AI.

Contact memory

Reads and writes the memory shared with calls and WhatsApp.

Opt-out keywords

STOP, HELP and START are handled before the model ever sees the text.

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The editor at a glance

A single screen with three columns. There’s no step-by-step wizard. The top bar holds the name and description, the Lumina badge, the Inbound / Outbound pill, the Active / Paused toggle, the FAQ and Tools buttons, and the save state: Draft saved, Unsaved changes or All changes saved.

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One agent, one direction

Agent Type is Inbound or Outbound. There’s no omnichannel type on SMS.
  • An inbound agent never texts first.
  • An outbound agent never picks up a stray inbound text on its number — but a customer replying to a conversation it started always reaches that same agent.
For a number that must both answer and start conversations, create one agent of each type on it.

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Who can see the SMS section

You need the SMS feature on your plan and SMS read and write permissions. Admin and Super Admin have them; a custom role must add the SMS module.
If SMS isn’t in the menu, it’s either the plan or the role.

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What SMS does NOT have

Worth saying early, because these are real differences from WhatsApp:

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What’s in this section

Create an SMS agent

The minimum fields to get it replying.

The prompt, FAQs and variables

How you instruct it, what it actually receives, and how to personalise it.

Channel, routing and behaviour

Number, agent type, who answers an inbound text, timeouts, memory and outcome tags.

Tools

API, End Chat, Handoff, Integration and Calendar.

The Send SMS tool

Let the agent text the customer or a third party mid-conversation.

Atlas, testing and going live

Build with Atlas, test the draft, check the summary, activate.

The Conversations inbox

Follow threads live, take over from the AI, hand back, and close.

Outbound chats and Salesflow

Start chats by hand, schedule them, or trigger them from a pipeline.

Compliance and opt-outs

STOP, HELP, START, the suppression list and A2P 10DLC registration.

What SMS costs

How conversations, tests, Atlas and the Send SMS tool consume credits.

Phone numbers

How to get the number the agent needs.

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Two things that surprise people

Saving publishes immediately. There’s no server-side draft and no version history. The Draft saved chip is a browser autosave, nothing more.
Your agent is already contributing to contact memory. Record to memory is on by default. Reading memory is opt-in; writing it is on unless you turn it off.See Contact memory.

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Next step

Create an SMS agent

The minimum fields to get it replying.