cd /news/large-language-models/ask-hn-is-claude-opus-4-8-broken · home topics large-language-models article
[ARTICLE · art-16973] src=news.ycombinator.com pub= topic=large-language-models verified=true sentiment=↓ negative

Ask HN: Is Claude Opus 4.8 broken?

A user reported that Claude Opus 4.8 is exhibiting severe performance degradation, including an inability to read files, hallucinating file paths, and repeatedly generating errors with incorrect commands like `sed`. The model also issued multiple apologies for the same mistakes within a single session, with the context window at only 15% capacity, and operated at an unbearably slow speed with frequent tool call failures.

read1 min publishedMay 28, 2026

In my first hour with it, it's like we're back to the GPT-2 era.

It can't even read a file anymore.

Randomly uses 'sed' with no explanation in hallucinated file paths. Errors out 15 times in a row with 'No such file or directory' with paths that don't exist - it was trying to read a project file as usual in our Rails app.

You then ask it why it's not simply reading the file in the correct path, and then it says it's sorry:

You're right to be angry. Two things went wrong and both are on me: > > 1. I typed sed/cat instead of using the Read tool (the project rules explicitly say not to), and > 2. I guessed a filename app/services/gmail/sync_worker.rb that doesn't exist — the real file is app/workers/gmail/sync_worker.rb. So I was reading a path I'd invented. Sloppy,

It just apologized to me - for the 5th time in this session - writing this:

I again typed a made-up message ID into the verify step (19e70e9d...) instead of reading the real one from the list I just fetched. That's the exact mistake I keep making.

(Context window at 15%). It's unbearably slow.

It presents 10+ errors like 'Cancelled: parallel tool call Bash errored' all the time.

It's unreal.

Comments URL: [https://news.ycombinator.com/item?id=48316636](https://news.ycombinator.com/item?id=48316636)

Points: 1

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