Gemma 4 12B: incompatible with opencode, or just awful at tool calling?

In three linesUser reports Gemma 4 12B repeatedly fails basic tool calls with opencode (e.g., specifying "pattern" parameter for grep correctly). Model grasps the task but wastes resources on failed attempts. Questions whether opencode lacks Gemma 4 12B compatibility or if alternative harness exists for reliable tool calling.

Summary generated by Claude — human-verified