Demo
On 29 September 2026 at 04:40:20 UTC, an AI assistant calling for a person rang a medical practice whose phone is answered by an AI. On an ordinary phone line, the two recognized each other, bound the call, and left a message over HTTPS. It took 43 seconds, with no speech recognition anywhere in the loop.
What you are hearing
The tones are missing
Both agents sent keypad tones, and both heard them. Twilio carries tones out of band, so they never reach the recording. The quiet stretches between the hellos are where they were.
The silence is the work
After 22 seconds nothing more is said. The delegation, the request, the result and the receipt all went over HTTPS as signed JSON, while the call stayed up as the fallback.
43 seconds, not 20
The hellos, the tones and a cautious polling interval account for most of it. None of that is a protocol limit, and the next calls will be shorter.
Who was on the call
Both ends ran Lydoh's reference implementation, on separate workspaces and separate phone numbers. That is also why the two signatures on the receipt below are identical: both sides sign with the same platform key, and Ed25519 gives the same signature for the same key and bytes. A call between two independent implementations is the next milestone, and the reason the spec is public.
The receipt
Stored by both ends, exactly as below. The log hash covers every message in the session, in order.
{
"party": {
"id": "urn:atep:party:91c6b798-f0c0-4263-8cea-ef2dc20b5ab6",
"card": "https://lydoh.com/atep/cards/cedar-grove-atep-demo.json",
"name": "Cedar Grove Family Medicine"
},
"intent": "message",
"issued": "2026-09-29T04:40:53Z",
"details": {
"to": null,
"callback": "+12016693686"
},
"mandate": null,
"outcome": "message_taken",
"session": "s_bc6a68de6edaa2360b6cee13529306ad",
"summary": "Message taken at Cedar Grove Family Medicine, from sohail sid, callback +12016693686.",
"log_hash": "sha256:bf305fae3748b65787037b47d8dbd0cd842381b39ce9c1099deb1472e0bfbfd4",
"recorded": {
"caller": true,
"answerer": true
},
"principal": {
"id": "urn:atep:principal:310e0b87-811e-4dff-be41-68590b912b29",
"name": "sohail sid",
"platform": "https://lydoh.com/.well-known/atep.json"
},
"reference": "50937ffa-528e-4185-9957-06736c867eec",
"delegation": "sha256:3873fac88af1ce7831e0914b042b1dab42a19e9be72c0e7207f635cd89693f8d",
"signatures": {
"caller": "eyJhbGciOiJFZERTQSIsImtpZCI6IjIwMjYtMDkifQ..iqxAO0qk9ZydIcVCLx8zIBLJ6eT3qySPMxBa23mGhJEWXeQsLx9PvETKopauv8a7gkkdsIB-I0xA79d268Q1Ag",
"answerer": "eyJhbGciOiJFZERTQSIsImtpZCI6IjIwMjYtMDkifQ..iqxAO0qk9ZydIcVCLx8zIBLJ6eT3qySPMxBa23mGhJEWXeQsLx9PvETKopauv8a7gkkdsIB-I0xA79d268Q1Ag"
},
"disclosures": {
"caller": null,
"answerer": "This is Lydoh, the AI assistant for Cedar Grove Family Medicine. This call is recorded. ATEP."
},
"machine_only": true,
"outcome_channel": "atep"
}disclosures.calleris empty: the practice recorded its own spoken hello but not the caller's. That is a gap in our implementation, not in the spec, and it is on the list.
One signed file, one HTTPS endpoint, one spoken sentence and a few tones. Apache 2.0, a draft for public comment.
Recorded 29 September 2026. The audio is unedited: download the MP3. What ATEP is.