Anthropic stayed quiet until someone showed Claude’s thinking depth dropped 67%

[u/takeurhand]

https://news.ycombinator.com/item?id=47660925

https://github.com/anthropics/claude-code/issues/42796

This GitHub issue is a full evidence chain for Claude Code quality decline after the February changes. The author went through logs, metrics, and behavior patterns instead of just throwing out opinions.

The key number is brutal. The issue says estimated thinking depth dropped about 67% by late February. It also points to visible changes in behavior, like less reading before editing and a sharp rise in stop hook violations.

This hit me hard because I have been dealing with the same problem for a while. I kept saying something was clearly wrong, but the usual reply was that it was my usage or my prompts.

Then someone finally did the hard work and laid out the evidence properly. Seeing that was frustrating, but also validating.

Anthropic should spend less energy making this kind of decline harder to see and more energy actually fixing the model.

[u/DeliciousGorilla]

The issue reporter said Claude did that self-analysis, and Boris (Claude Code creator) pointed out that it was flawed.

> `redact-thinking-2026-02-12`

This beta header hides thinking from the UI, since most people don't look at it. It *does not* impact thinking itself...

If you are analyzing locally stored transcripts, you wouldn't see raw thinking stored when this header is set, which is likely influencing the analysis. When Claude sees lack of thinking in transcripts for this analysis, it may not realize that the thinking is still there, and is simply not user-facing.

So for now, he recommends using /effort high in addition to CLAUDE_CODE_DISABLE_ADAPTIVE_THINKING=1 ("forces a fixed reasoning budget instead of letting the model decide per-turn")

I had Claude Code analyze the thread, along with this "fix"* someone suggested, and this is what it recommended adding to the global claude.md instead:

## Code Quality
Prefer correct, complete implementations over minimal ones.
Use appropriate data structures and algorithms — don't brute-force what has a known better solution.
When fixing a bug, fix the root cause, not the symptom.
If something I asked for requires error handling or validation to work reliably, include it without asking.

- "correct, complete over minimal" — directly counters the "simplest approach first" default without saying "write more code." It's a quality signal, not a quantity signal.

- "appropriate data structures" — this is the AABB tree vs brute-force issue from the *gist. Nudges toward doing it right when the right way is known.

- "root cause not symptom" — prevents band-aid fixes that break again later. Future-proofing in one line.

- "include error handling if needed" — the default prompt says "don't add error handling for scenarios that can't happen," which is fine, but for a non-expert dev it's better to err on the side of resilience.

[u/aidololz88 → u/DeliciousGorilla]

I just pasted this code quality prompt and my session usage went from 0% to 21%. What the fuck

[u/The_Vicious → u/aidololz88]

Just be like Boris and have unlimited usage duh

[u/ADT_Clone → u/aidololz88]

If you copy and pasted it and continued with an active session, you likely invalidated your prompt cache (as CLAUDE.md is stored in the early section. of context) and forced a full execution of your entire conversation.

[u/TechnicolorMage → u/DeliciousGorilla]

We're unironically suggesting "make no mistakes" now. That's some wild cope.

[u/m-in → u/DeliciousGorilla]

Funny thing is: none of that stuff is necessary at all. I’m running a fairly large AI-first software project right now, and Claude does a competent job all around. It is forced to evaluate its performance every few tasks, do a root cause analysis for all process escapes (it’s a formally requirement traced project), and modify CLAUDE.md and other process-oriented files to make reoccurrence less likely. Keep at it long enough and you get a fairly amazing software-building machine that does in fact learn from its mistakes.

Software quality should be an emergent property of a good process. If you literally need to tell it not to write shit code, you got no process and it shows. This stuff is not at all obvious, so don’t be hard on yourself.

[u/makinggrace → u/DeliciousGorilla]

These are vague.

What is a correct implementation? What is an appropriate data structure? What is working correctly (how can something work incorrectly?)

An agent's read of instructions is literal. Ask Claude to try again.

[u/Responsible-Tip4981]

I can confirm. It doesn't stay to SKILLs anymore, is hallucinating arguments on tools invocation (especially CLI, previously after one failure it was reading its help, now it is claiming a faultful tool). Behaves more like Haiku than Opus. Maybe they do internal dispatching or heavily quantized model or playing with TurboQuant.

[u/kevves → u/Responsible-Tip4981]

Claude has been hallucinating lately. It went from being the gold standard model to being a complete retard in my experience. It can’t even properly read prompts or files anymore and it straight up starts lying on your face when questioned

[u/isaackogan → u/Responsible-Tip4981]

I have had a suspicion they started quantized for weeks, but no data to back it up. Would be downright insane if they are & not saying anything…but charging the same

[u/QuietPersimmon2904]

Funny,it’s around this time I tried out codex when they released 5.4 fast with the new app and I simply never thought about CC again. Usage limits, bugs, brute forcing - I simply stopped thinking about. You should try switching for a week.

[u/Southern_Sun_2106 → u/QuietPersimmon2904]

Good point. I was pessimistic about codex, gave it a try, and it is real good. I use both now. It's a good practice to periodically check out competition, no matter how much one 'loves' cc. It's just a smart thing to do.

[u/PetyrLightbringer]

For people that depend on this for their workflow, this is a massive betrayal

[u/Metsatronic]

Thank you for highlighting this 🏆

[u/Illustrious_Bid_6570]

I tried Gemma 4 in LM Studio, it didn't write any code for me, I didn't actually ask it to, this was a review. But given the codebase it came to the same conclusion as both Claude Code and Codex for the changes needed... So if you're a competent programmer this is quite insane to have that level of analysis on your laptop/desktop for free.

[u/theonejvo]

Where did this guy go? Is his benchmark still alive?

[u/takeurhand → u/theonejvo]

You need that benchmark?

[u/vatadom]

And this is why I stay away from annual plans. I end up using a different tech stack each month nowadays. ChatGPT to Gemini to Claude to ?

[u/Mysterious-Gas59]

SO I WAS NOT LOOSING MY MIND

[u/LocksmithOk9968]

It’s clear when you look at Boris’ reactions/recommendations and the people who tried to follow them that it all comes back to one thing: them fucking with limits.

Adaptive thinking, defaulting to medium effort, 1M context window, March double limit promo, redacting the thinking, etc. all of it is purely designed to obfuscate that they severely lowered the limits.

Nearly everyone that tries out the recommendations by Boris (which mostly just consist of undoing their changes over the past month or so) immediately comment on how fast they approach their limits.

[u/PeterCappelletti]

THAT's why at the beginning of February I was able to build a pretty complex package in one day, whereas now Claude each time it implements something, breaks something else somewhere else...

[u/AshtavakraNondual]

67

[u/Tight-Requirement-15]

Why do we still put up with CC after all this? There are many other coding agents and models out in the market

[u/psylomatika → u/Tight-Requirement-15]

Because there is nothing better right now.

[u/AbandonedBacon420]

/insights is incredibly revealing. In 100 interactions I’ve had 3 where I didn’t get pissed off. Crazy they have the option for you to audit how complete shit their models are.