SMS AI Agents

The same agent concept that answers your calls can answer your texts. Set an agent's channel to SMS, wire it to a number, and inbound messages get an AI reply within seconds.

How it works

• An inbound text arrives on a number with an SMS agent assigned.
• HUM waits a brief debounce window so rapid-fire messages are answered once, together.
• The agent reads the conversation history, uses its tools if needed, and sends one reply.

Replies are plain text, kept SMS-length, and the agent is instructed to hand off rather than dead-end ("I can't do that" is never the final answer).

Setting it up

• Create an agent (or duplicate an existing one) and set its channel to SMS, with instructions written for texting — short, plain replies.
• On the number (Numbers → open the number), set the SMS agent.
• Text the number to try it.

Built-in SMS tools

SMS agents ship with thread-management tools out of the box: assigning the conversation to a human, closing the conversation, transferring to another agent, scheduling a follow-up text, knowledge lookup, and reporting structured outcomes. Your organization's HTTP tools from the Tool Registry work here too.

Human takeover

Any teammate can jump into an AI thread from the Messages inbox — the AI pauses automatically (and the AI can also assign threads to humans itself). Resume the AI when the human part is done.

Guardrails

Per-agent anti-loop budgets cap how many AI replies can fire in a rolling window, how many tool calls a single turn may use, and how long a reply can be. Opt-outs are honored before the AI ever sees the message. If the AI can't produce a usable reply, an optional fallback message keeps the contact from being ghosted.