Key Takeaways
- list_devices via MCP wraps REST device health — not a first-party Cursor or Claude plugin, and not MCP server source.
- Example prompt: call list_devices before send_sms; refuse if pairing is unhealthy.
- SKU device caps still apply (Free/Developer 1; Starter 2 / Pro 5 / Business 15). Listing cannot invent radios.
- Live fields live in Developer Center. Do not invent paths.
- A green tool result is not a DLR. The SIM still needs airtime.
- You bring the Android and operator credit. We meter devices and send volume.
List health before any send
List_devices MCP tool is the agent’s pairing check: last-seen, battery, which SIM is eligible. It wraps the same Android SMS gateway REST API. Link the MCP server overview; do not rewrite it.
Sending without list_devices is how you text from a phone that has been in a drawer since Tuesday.
Example agent prompt
“Call list_devices before send_sms. If none are healthy, tell the operator and stop. Do not invent device ids. Do not pick a promo radio for OTP. Do not dump API keys. If the list is stale, refresh once, then fail closed.” Live field names: Developer Center. Spec context: MCP specification.
What list_devices should return
| Signal | Agent may send? | Note |
|---|---|---|
| Paired + recent last-seen | Yes, on that lane | Still not a DLR |
| Offline / OEM sleep | No | Offline checklist |
| Spare charged | Only if SKU allows | Listing a 3rd phone on Starter (2) is not a send right |
| Unknown payload | No | Fail closed; check Developer Center |
Fail closed
Tools must not send when the list is empty. Multi-tenant wrappers pass the tenant’s key — see the multi-tenant prompt sibling. Pairing walks: device setup guide.
Cost
You bring each Android and operator SMS credit. We meter devices plus platform volume. Free: 1 device / 300 SMS lifetime / 300 contacts. See device and SMS volume pricing.
Checklist
- Overview linked; no plugin claim.
- Prompt requires list before send.
- No invented device ids.
- OTP vs promo radios honored.
- SKU caps respected.
- No MCP server source dump.
- Developer Center for live fields.
- Last-seen treated as stale after a documented window.
Next steps
Error copy for the model is the error-handling prompt sibling. Rate limits are a different prompt — do not clone them here.
Related product pages
Jump to the live product docs for this topic—not another long-form article.
- SMS API documentationLive endpoint reference
- device and SMS volume pricingPlans and allowances
- Android SMS gateway product guideDefinition, product, and how to buy
- download the Android gateway appGet the APK
