For me, Opus 4.6 isn't working quite right currently, and I often use GLM 5.1 instead. I'd prefer to use peak Opus over GLM 5.1, but GLM 5.1 is an adequate fallback. It's incredible how good open-weight models have gotten.
i have a feeling its nearing opus 4.5 level if they could fix it getting crazy after like 100k tokens.
From my testing it was ok until 145k tokens, the largest context I had before switching to a new session. I think Z.ai officially said it should be good until 200k tokens.
Using it in Open Code is compacting the context automatically when it gets too large.