Opus 4.7 Benchmark Regressions Quantified: MRCR Collapses 59%, First Opus Model to Receive Majority Negative Reception

New model doesn't mean better model. The r/ClaudeAI community learned this the hard way.

The top post on r/ClaudeAI hit 2,757 upvotes with 682 comments calling Opus 4.7 "a serious regression, not an upgrade." Cross-platform sentiment was uniformly negative: 818 upvotes on r/singularity, 474 on r/OpenAI, 220 on r/ChatGPT. This is the first Opus release to receive majority negative reception.

The complaints aren't vibes. Independent benchmarks confirm real regressions. Multi-Round Context Retrieval (MRCR) collapsed from 78.3% to 32.2%. That's a 59% relative decline. NYT Connections Extended dropped from 94.7% to 41.0%. Thematic Generalization fell from 80.6 to 72.8. Even Anthropic's own BrowseComp regressed from 84.0% to 79.3%.

The model wins 12 of 14 official benchmarks. But the regressions cluster in reasoning and context tasks, which is exactly what power users and Claude Code practitioners rely on daily.

It gets worse. The new "adaptive thinking" feature silently broke existing API integrations. Setting budget_tokens now returns a 400 error. Thinking content is omitted from responses by default without raising errors, causing silent quality degradation. Third-party SDKs haven't updated their supportsAdaptiveThinking() checks. A 254-upvote post called adaptive thinking "a joke."

There's a stealth tax on top of it. Opus 4.7's new tokenizer produces 1.0 to 1.35x more tokens for the same input text, with code and structured data hitting the upper end. The per-token price didn't change. Your per-request cost went up 0-35% anyway.

But here's the counter-narrative I don't want to ignore: a 310-upvote post praises Opus 4.7's Research mode as spawning 1,000+ source queries, exceeding anything 4.6 could do. Boris Cherny, the creator of Claude Code, published tips suggesting users are bloating context with too many installed skills, causing 4.7 to eat tokens faster.

My take: pin to Opus 4.6 for context-heavy and reasoning-intensive workflows. Test 4.7 mode-by-mode before migrating anything. And benchmark your actual token counts against 4.6 baselines before you trust the "unchanged pricing."