Build an SMS Support Agent with Follow-Up on Telnyx Edge Compute

Telnyx has released a code example demonstrating an SMS support agent built on its Edge Compute platform. The agent uses durable actors from the Agent SDK to maintain conversation history, process messages asynchronously, and schedule follow-up messages if the customer does not reply within 24 hours. The example integrates with Telnyx AI Inference and Messaging APIs, with authentication handled via a zero-credential binding.

A lot of AI support demos stop after one reply. Customer asks a question. Model answers. Demo done. Real support usually needs a little more than that. You need message history, background processing, a way to send the reply, and sometimes a follow-up if the customer goes quiet. This example builds that flow as an SMS support agent on Telnyx Edge Compute. Code: https://github.com/team-telnyx/telnyx-code-examples/tree/main/sms-support-agent-with-followup https://github.com/team-telnyx/telnyx-code-examples/tree/main/sms-support-agent-with-followup The app receives inbound SMS messages, routes each sender to a durable Agent SDK actor, calls Telnyx AI Inference, sends a reply through Telnyx Messaging, and schedules a 24-hour follow-up. The flow: php Inbound SMS - /webhooks/sms - SupportAgent.receive - this.messages.add - this.queue "process" - Telnyx AI Inference - Telnyx Messaging reply - this.schedule 24h, "followup" The important part is that the webhook does not need to wait on the LLM. It stores the message and queues the work, so the webhook can acknowledge quickly. The SupportAgent extends the Agent SDK Agent class from @telnyx/edge-runtime . It uses: this.messages.add for durable conversation history this.messages.toOpenAI to format history for the model this.queue "process" for background AI processing this.schedule 86400, "followup" for the next-day check-in this.setState and this.getState for sender/recipient state this.env.TELNYX for zero-credential Telnyx API accessThe telnyx binding in telnyx.toml handles API auth: telnyx binding = "TELNYX" Then the agent can call: await this.env.TELNYX.ai.openai.chat.createCompletion ... await this.env.TELNYX.messages.send ... No API key is hardcoded in the application code. POST /webhooks/sms receives Telnyx message.received webhooks POST /debug/message simulates an inbound SMS for testing GET /debug/state inspects an actor state for a sender GET /health/liveness and GET /health/readiness are health checksAfter deploying, you can simulate an inbound SMS: curl -X POST https://sms-support-agent-<id .telnyxcompute.com/debug/message \ -H "Content-Type: application/json" \ -d '{ "from":"+15551230000", "to":"+15559870000", "text":"How do I send an SMS?" }' Response: { "action": "queued", "from": "+15551230000", "to": "+15559870000" } For real SMS, set your Telnyx Messaging Profile webhook URL to: https://sms-support-agent-<id .telnyxcompute.com/webhooks/sms Then text the Telnyx number. The follow-up task runs 24 hours later. It checks the last message in the durable conversation history. If the last message is still from the assistant, the customer has not replied since the AI answer, so the agent sends: Did that solve your problem? Reply yes or no, or ask for a human. If the customer already replied, it skips the nudge. That is the piece I like. The agent is not just a stateless webhook. It has memory and scheduled work. Before shipping this pattern in a real support workflow, I would add: But as a starter pattern, this is a clean way to build an AI support agent that can answer, remember, and follow up. Resources: