opencode + ollama suddenly not working correctly, outputting prompt objects in json #37543

Description

I had a lot of success working with the qwen2.5-coder:14b on Ollama + opencode. I was able to get a lot of work done in a medium size project and was very pleased with the results. This was throughout June, didn't use it much this month until now. The only real change is updating OpenCode.

I went to use this setup to create a (relatively) simple python script and all of a sudden it wouldn't do any work. It would output a json object describing what it should be doing, or at best a todo list that it never advanced through. It would just "think" about it repeatedly over a few minutes.

I also tried using gemma4:12b, but got the same results.

Plugins

none

OpenCode version

1.18.3

Steps to reproduce

1. Launch opencode with ollama ollama launch opencode --model gemma4:12b (mature project, empty folder, doesn't matter).
2. Ask a basic question: What version of C# does this project use?
3. Get back a prompt object in json, e.g.

{"name": "explore", "arguments": {"task_id": null, "subagent_type": "quick", "prompt": "I need to find a class named 'Foo'. Please search the codebase for this class and locate any relevant files."}}

That's a weird one, usually the prompt in the object is just a rewording of what my prompt.

Screenshot and/or share link

https://opncd.ai/share/TWV6fZ3I

Operating System

Windows 11 with WSL

Terminal

Windows Terminal