# Does cartesia/sonic-3-latest still route to Sonic 3.5, or Sonic 3?
**URL:** https://community.livekit.io/t/does-cartesia-sonic-3-latest-still-route-to-sonic-3-5-or-sonic-3/1149
**Category:** Agents
**Tags:** livekit-inference, cartesia
**Created:** [May 17, 2026, 9:38am UTC](https://community.livekit.io/t/does-cartesia-sonic-3-latest-still-route-to-sonic-3-5-or-sonic-3/1149 "2026-05-17T09:38:41Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@Abdulaziz](https://community.livekit.io/u/Abdulaziz)
#### Post date: [May 17, 2026, 9:38am UTC](https://community.livekit.io/t/does-cartesia-sonic-3-latest-still-route-to-sonic-3-5-or-sonic-3/1149/1 "2026-05-17T09:38:41Z")
Hey team,
Back around April 30, `cartesia/sonic-3-latest` was added to LiveKit Inference after this thread: [Support for Cartesia sonic-3-latest model](https://community.livekit.io/t/support-for-cartesia-sonic-3-latest-model/994)
At the time, my understanding was that Cartesia’s `sonic-3-latest` pointed to the new Sonic 3.5 preview, so using `cartesia/sonic-3-latest` through LiveKit Inference should have routed to Sonic 3.5.
Cartesia now documents explicit Sonic 3.5 model IDs:
- `sonic-3.5`
- `sonic-3.5-2026-05-04`
- `sonic-latest`
But in LiveKit Inference today, I’m seeing:
- `cartesia/sonic-3-latest` works
- `cartesia/sonic-3` works
- `cartesia/sonic-3.5` returns `model not found`
- `cartesia/sonic-3.5-2026-05-04` returns `model not found`
- `cartesia/sonic-latest` returns `model not found`
Can you confirm what `cartesia/sonic-3-latest` currently routes to?
Specifically:
1. Is `cartesia/sonic-3-latest` still Sonic 3.5, or is it now Sonic 3?
2. If it is Sonic 3, is there a supported LiveKit Inference model ID for Cartesia Sonic 3.5?
3. Should we expect `cartesia/sonic-3.5` or `cartesia/sonic-latest` support soon?
Thanks.
---
### Author:  [@Muhammad\_Usman\_Bashir](https://community.livekit.io/u/Muhammad_Usman_Bashir)
#### Post date: [May 17, 2026, 1:25pm UTC](https://community.livekit.io/t/does-cartesia-sonic-3-latest-still-route-to-sonic-3-5-or-sonic-3/1149/2 "2026-05-17T13:25:21Z")
@Abdulaziz, your empirical testing is the right method. Verified on main (`livekit-agents/livekit/agents/inference/tts.py`): `inference.TTS` doesn’t validate model names client-side; the string passes straight through to the gateway, so “model not found” is a gateway-level rejection against LK’s internal allowlist.
The mapping from `cartesia/sonic-3-latest` to its upstream Cartesia model ID lives in LK Cloud’s Inference config, not in OSS code. Only @CWilson or @darryncampbell can authoritatively answer:
- Current routing: what `cartesia/sonic-3-latest` resolves to today (Sonic 3 vs Sonic 3.5)
- Pointer behavior: whether it auto-follows Cartesia’s sonic-latest upstream, or is pinned to a specific version
- 3.5 ID timeline: ETA on adding `cartesia/sonic-3.5`, `cartesia/sonic-3.5-2026-05-04`, and `cartesia/sonic-latest` to the Inference allowlist
The “Support for Cartesia `sonic-3-latest`” thread you linked is the right precedent channel for these adds. Pinging the team here to surface the `3.5` question.
---
### Author:  [@darryncampbell](https://community.livekit.io/u/darryncampbell)
#### Post date: [May 27, 2026, 7:26am UTC](https://community.livekit.io/t/does-cartesia-sonic-3-latest-still-route-to-sonic-3-5-or-sonic-3/1149/3 "2026-05-27T07:26:18Z")
> [@Abdulaziz](#):
>
> - `cartesia/sonic-3.5` returns `model not found`
> - `cartesia/sonic-3.5-2026-05-04` returns `model not found`
> - `cartesia/sonic-latest` returns `model not found`
I see a change was pushed last night to the Inference product meaning these should now resolve.
1. Is `cartesia/sonic-3-latest` still Sonic 3.5, or is it now Sonic 3? → This is pointing at Sonic-3
2. If it is Sonic 3, is there a supported LiveKit Inference model ID for Cartesia Sonic 3.5? → Yes, the 3 models you listed that were previously ‘not found’ should now point to 3.5
3. Should we expect `cartesia/sonic-3.5` or `cartesia/sonic-latest` support soon? → Sorry I missed this message when it was originally posted