Voice AI Architecture

Your voice AI is two independent layers

When the reasoning model goes down, the call stays live. What the customer hears next is a design choice.

Customer on a live call

Layer 1

Voice stack

Telephony & speech — e.g. Retell. Keeps the call alive.

Layer 2

Reasoning model

The AI brain, via API — the layer that went dark in June.

● can go down — outage, ban, rate limit

— what happens next is a design choice —

✕No failover

The agent goes silent mid-sentence. The customer waits, gets nothing, hangs up — and remembers it.

✓With failover

The system reroutes to a backup model or hands off to a human. The customer never hears the gap.