> ## Documentation Index
> Fetch the complete documentation index at: https://docs.erdo.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# SMS Messaging

> Have an Erdo agent send outbound SMS — qualify a lead, confirm a detail, follow up — consent-gated and opt-out-aware, no setup required.

# SMS Messaging

An Erdo agent can send outbound **SMS** on your behalf through Erdo's managed number — the same
Erdo-managed model as [Voice Calls](/voice). No account or carrier setup to connect; just ask the
agent to text someone.

> "Text +1 415 555 0142 to confirm their demo on Thursday at 2pm."

Like voice calls, every send is **approval-gated** (you confirm it in chat first) and requires a
**consent basis** — a concrete reason the message is permitted (explicit opt-in, an existing
business relationship, an internal test).

## Opt-out is enforced

Recipients who reply **STOP** are added to your organization's suppression list, and any further
send to that number is **blocked before it leaves** — the agent is told the recipient opted out and
no credit is charged. (STOP is also enforced at the carrier level, so opt-out is honored even
on the very first reply.) Suppression is per-organization.

## Sending is rate-limited

Erdo caps how many messages can go out so a loop or a mistake can't spam anyone: there's a
**per-recipient** limit (you can't blast one number) and a **per-organization** limit over a rolling
window. A send that would exceed either is **blocked before it leaves** and not charged — the agent
is told to back off. A logical send can also carry an **idempotency key** so a retry never sends the
same message twice. These limits, opt-out, and consent apply across every channel.

## What the agent does

The `send_sms` capability:

* Validates the number, body, and consent basis.
* Checks the opt-out list and your credit balance first.
* Sends from Erdo's number and records the message.
* Charges a small flat credit cost per message, only after the message is accepted (a blocked or
  opted-out send is never charged).

## Lead outreach

SMS pairs with [Voice](/voice) for lead outreach loops: text a list, capture replies, and let Erdo
qualify and follow up. Combined with datasets and workstreams, a whole list can be worked
end-to-end.

<Note>
  Outbound SMS uses Erdo's shared number. Replies and richer channels (WhatsApp, RCS) are on the
  roadmap.
</Note>