AIHubMix provider: streaming completes output but errors near end with ZodError (invalid_union: reason/part/delta)

[qiyuanhuakai]

Description

When using the built-in AIHubMix provider, OpenCode can stream most of the assistant output, but near the end of the stream it throws a ZodError and marks the request as failed.

The error is an invalid_union with fields like:

path ["reason"]: expected string, received object
path ["part"]: expected object, received undefined
path ["delta"]: expected string, received undefined

I use the built-in provider XIAOMI now, and it just works well.

Plugins

at first with oh-my-opencode, and it can be reproduced with none

OpenCode version

1.1.8, and can be reproduced in 1.1.6 and 1.1.1

Steps to reproduce

Use the bulit-in AIHubMix provider:

• Select an AIHubMix model.
• Send any prompt (e.g. hello / 你好？).
• Observe streaming output appears, then near completion OpenCode throws ZodError. Model tested:
• Claude Haiku 4.5 (built-in)
• GPT-5.2 (built-in)
• glm-4.7 (built-in)
• grok-4-1-fast-non-reasoning(added by myself)
• gemini-3-flash-preview (added by myself)

Screenshot and/or share link

Operating System

Ubuntu 24.04, in WSL2

Terminal

Windows Terminal