Claude Code just made 1M context the default. No extra charge compared to before — that’s a nice change.

But MRCR hasn’t changed. At 1M tokens, Opus 4.6 sits at 78% retrieval accuracy, which means 1 in 4 multi-needle retrievals still fails. There are already GitHub issues about it — model loses track of earlier decisions, starts going in circles, forgets things from earlier in the session. Anthropic calls it “context rot.”

My own workflow doesn’t really need 1M. I run around 20k, clear often, and split bigger tasks into subagents or subplans. At that scale retrieval is basically perfect and the context stays clean.

Having 1M available without paying extra is handy when you actually need it. But defaulting to it just because it’s there — I’m not sold on that.

One side note: the opusplan mode I use doesn’t default to 1M context. So even within Claude Code, it’s not universal.