GPT-6 Astra Ultrafast fails: serviceTier "ultrafast" rejected #53538

Description

GPT-6 Astra Ultrafast is listed as an available model in OpenCode 1.18.34 (TUI), but every request immediately fails with:

invalid openai provider options

The debug log shows that OpenCode sets:

"serviceTier": "ultrafast"

but the bundled OpenAI provider rejects it:

Invalid option: expected one of
"auto" | "flex" | "priority" | "default"

path: ["serviceTier"]

openai/gpt-6-astra and openai/gpt-6-astra-fast work with the same OAuth account. Ultrafast also works for this account in the official Codex client.

Expected behavior

openai/gpt-6-astra-ultrafast should work since OpenCode already exposes the model and maps it to serviceTier: "ultrafast".
It looks like the bundled OpenAI provider/AI SDK has an older serviceTier validation schema that does not yet accept "ultrafast".

Plugins

No response

OpenCode version

1.18.34

Steps to reproduce

1. Select gpt-6-astra-ultrafast
2. Write a prompt, e.g. 'Say hello'
3. error: invalid openai provider options

Screenshot and/or share link

No response

Operating System

Ubuntu 26.04.1 LTS

Terminal

Ghostty