Opus 4.5 is not the normal AI agent experience that I have had thus far • Hacker News Board

Re: Opus 4.5 is not the normal AI agent experience that I have had thus far

#881

Post by pugworthy » Wed, Jan 07, 2026, 6:29 PM UTC

OccamsMirror wrote: post #526

pugworthy wrote: post #478

Earlier quoted context omitted.

To me, this doesn't show the weakness of current models, it shows the variability of prompts and the influence on responses. Because without the prompt it's hard to tell what influenced the outcome. I had this long discussion today with a co-worker about the merits of detailed queries with lots of guidance .md documents, vs just asking fairly open ended questions. Spelling out in great detail what you want, vs just g…

So which approach worked better?

Challenging to answer, because we're at different levels of programming. I'm Senior / Architect type with many years of experience programming, and he's an ME using code to help him with data processing and analysis.

I have a hunch if you asked which approach we took based on background, you'd think I was the one using the detailed prompt approach and him the vague.

Re: Opus 4.5 is not the normal AI agent experience that I have had thus far

#882

Post by causal » Wed, Jan 07, 2026, 6:33 PM UTC

deanc wrote: post #538

mcv wrote: post #133

Opus 4.5 ate through my Copilot quota last month, and it's already halfway through it for this month. I've used it a lot, for really complex code. And my conclusion is: it's still not as smart as a good human programmer. It frequently got stuck, went down wrong paths, ignored what I told it to do to do something wrong, or even repeat a previous mistake I had to correct. Yet in other ways, it's unbelievably good. I ca…

People are completely missing the points about agentic development. The model is obviously a huge factor in the quality of the output, but the real magic lies in how the tools are managing and injecting context in to them, as well as the tooling. I switched from Copilot to Cursor at the end of 2025, and it was absolute night and day in terms of how the agents behaved.

In my experience GPT-5 is also much more effective in the Cursor context than the Codex context. Cursor deserves props for doing something right under the hood.

Re: Opus 4.5 is not the normal AI agent experience that I have had thus far

#883

Post by dpc_01234 » Wed, Jan 07, 2026, 6:33 PM UTC

JDye wrote: post #813

klaussilveira wrote: post #325

Earlier quoted context omitted.

I made a similar comment on a different thread, but I think it also fits here: I think the disconnect between engineers is due to their own context. If you work with frontend applications, specially React/React Native/HTML/Mobile, your experience with LLMs is completely different than the experience of someone working with OpenGL, io_uring, libev and other lower level stuff. Sure, Opus 4.5 can one shot Windows utilit…

We have an in-house, Rust-based proxy server. Claude is unable to contribute to it meaningfully outside of grunt work like minor refactors across many files. It doesn't seem to understand proxying and how it works on both a protocol level and business logic level. With some entirely novel work we're doing, it's actually a hindrance as it consistently tells us the approach isn't valid/won't work (it will) and then ent…

> We have an in-house, Rust-based proxy server. Claude is unable to contribute to it meaningfully outside

I have a great time using Claude Code in Rust projects, so I know it's not about the language exactly.

My working model is is that since LLM are basically inference/correlation based, the more you deviate from the mainstream corpus of training data, the more confused LLM gets. Because LLM doesn't "understand" anything. But if it was trained on a lot of things kind of like the problem, it can match the patterns just fine, and it can generalize over a lot layers, including programming languages.

Also I've noticed that it can get confused about stupid stuff. E.g. I had two different things named kind of the same in two parts of the codebase, and it would constantly stumble on conflating them. Changing the name in the codebase immediately improved it.

So yeah, we've got another potentially powerful tool that requires understanding how it works under the hood to be useful. Kind of like git.

Re: Opus 4.5 is not the normal AI agent experience that I have had thus far

#884

Post by ndesaulniers » Wed, Jan 07, 2026, 6:37 PM UTC

OldGreenYodaGPT wrote: post #33

Most software engineers are seriously sleeping on how good LLM agents are right now, especially something like Claude Code. Once you’ve got Claude Code set up, you can point it at your codebase, have it learn your conventions, pull in best practices, and refine everything until it’s basically operating like a super-powered teammate. The real unlock is building a solid set of reusable “skills” plus a few agents for th…

Thanks for the example! There's a lot (of boilerplate?) here that I don't understand. Does anyone have good references for catching up to speed what's the purpose of all of these files in the demo?

Re: Opus 4.5 is not the normal AI agent experience that I have had thus far

#885

Post by hu3 » Wed, Jan 07, 2026, 6:39 PM UTC

mattfrommars wrote: post #301

I’ve been saying this a countless time, LLM are great to build toy and experimental projects. I’m not shaming but I personally need to know if my sentiment is correct or not or I just don’t know how to use LLMs Can vibe coder gurus create operating system from scratch that competes with Linux and make it generate code that basically isn’t Linux since LLM are trained on said the source code … Also all this on $20 plan…

No human would pass that bar.

Yet you expect $20 of computing to do it.

Re: Opus 4.5 is not the normal AI agent experience that I have had thus far

#886

Post by PaulHoule » Wed, Jan 07, 2026, 6:42 PM UTC

mnky9800n wrote: post #765

danfritz wrote: post #733

Every time I see a post like this on HN I try again and every time I come to the same conclusion. I have never see one agent managing to pull something off that I could instantly ship. It still ends up being very junior code. I just tried again and ask Opus to add custom video controls around ReactPlayer. I started in Plan mode which looked overal good (used our styling libs, existing components, icons and so on). I…

I always assume the person either didn't use coding agents in a while or its their first time. don't get me wrong, i love claude code, but my students are still better at getting stuff done that i can just approve and not micromanage. thats what i think everyone is missing from their commentary. you have to micromanage a coding agent. you don't have to micromanage a good student. when you dont need to micromanage any…

Around a Uni I think a lot about what students are good at and what they aren't good at.

I wouldn't even think about hiring a student to do marketing work. They just don't understand how hard it is to break through people's indifference and lack the hustle. I want 10-100x more than I get out of them.

Photos in The Cornell Daily Sun make me depressed. Students take a step out the door, take a snap, then upload it. I think the campus is breathtakingly beautiful and students just don't do the work to take good photos that show it.

In coding it is across the map. Even when I am happy with the results they still do the first 80% that takes another 80% to put in front of customers. I can be really proud of how it turned out in the end despite them missing the point of the design document they were handed.

I was in a game design hackathon where most of the winners were adults or teams with an adult on them. My team won player's choice. I'll take credit for my startup veteran talent of fearlessly demonstrating broken software on stage and making it look great and doing project management with that in mind. One student was solid on C# and making platformers in Unity. I was the backup programmer who worked like a junior other than driving them crazy slowing them down with relentlessly practical project management. The other student made art that fit our game.

We were at each other's throats at the end and shocked that we won. I think I understood the value everybody brought but I'm not sure my teammates did.

Re: Opus 4.5 is not the normal AI agent experience that I have had thus far

#887

Post by rootusrootus » Wed, Jan 07, 2026, 6:43 PM UTC

3D30497420 wrote: post #751

klaussilveira wrote: post #325

Earlier quoted context omitted.

I made a similar comment on a different thread, but I think it also fits here: I think the disconnect between engineers is due to their own context. If you work with frontend applications, specially React/React Native/HTML/Mobile, your experience with LLMs is completely different than the experience of someone working with OpenGL, io_uring, libev and other lower level stuff. Sure, Opus 4.5 can one shot Windows utilit…

I'll second this. I'm making a fairly basic iOS/Swift app with an accompanying React-based site. I was able to vibe-code the React site (it isn't pretty, but it works and the code is fairly decent). But I've struggled to get the Swift code to be reliable. Which makes sense. I'm sure there's lots of training data for React/HTML/CSS/etc. but much less with Swift, especially the newer versions.

I had surprising success vibe coding a swift iOS app a while back. Just for fun, since I have a bluetooth OBD2 dongle and an electric truck, I told Claude to make me an app that could connect to the truck using the dongle, read me the VIN, odometer, and state of charge. This was middle of 2025, so before Opus 4.5. It took Claude a few attempts and some feedback on what was failing, but it did eventually make a working app after a couple hours.

Now, was the code quality any good? Beats me, I am not a swift developer. I did it partly as an experiment to see what Claude was currently capable of and partly because I wanted to test the feasibility of setting up a simple passive data logger for my truck.

I'm tempted to take another swing with Opus 4.5 for the science.

Re: Opus 4.5 is not the normal AI agent experience that I have had thus far

#888

Post by PaulHoule » Wed, Jan 07, 2026, 6:46 PM UTC

alternatex wrote: post #841

enraged_camel wrote: post #760

Earlier quoted context omitted.

I find anecdotes like yours bewildering, because I've been using Opus with Vue.js and it crushes everything I throw at it. The amount of corrections I need to make tend to be minimal, and mostly cosmetic. The tasks I give it are not trivial either. Just yesterday I had it create a full-blown WYSIWYG editor for authoring the content we serve through our app. This is something that would have taken me two weeks, give o…

Created a WYSIWYG editor or copied it off the internet like your average junior would, bugs included? If that editor is very complicated (as they usually are) it makes sense to just opt for a library. If it's simple then AI is not required and would only reduce familiarity with how it works. The third option is what you did and I feel like it's the option with the lowest probability of ending up with a quality soluti…

There is contenteditable and EditContext hese days, it's not that hard to make a simple WYSIWYG editor. An LLM could figure out how to operationalize these things quicker than I could.

Re: Opus 4.5 is not the normal AI agent experience that I have had thus far

#889

Post by Rapzid » Wed, Jan 07, 2026, 6:51 PM UTC

OldGreenYodaGPT wrote: post #55

dmbche wrote: post #34

Earlier quoted context omitted.

Oh! An ad!

lol does sound like and ad, but is true. Also forgot about hooks use hooks too! I just use voice to text then had claude reword it. Still my real world ideas

Exactly what an ad would say.

Re: Opus 4.5 is not the normal AI agent experience that I have had thus far

#890

Post by pluralmonad » Wed, Jan 07, 2026, 6:57 PM UTC

troupo wrote: post #208

spaceman_2020 wrote: post #54

Earlier quoted context omitted.

I really think a lof of people tried AI coding earlier, got frustrated at the errors and gave up. That's where the rejection of all these doomer predictions comes from. And I get it. Coding with Claude Code really was prompting something, getting errors, and asking it to fix it. Which was still useful but I could see why a skilled coder adding a feature to a complex codebase would just give up Opus 4.5 really is at a…

> Opus 4.5 really is at a new tier however. It just...works. Literally tried it yesterday. I didn't see a single difference with whatever model Claude Code was using two months ago. Same crippled context window. Same "I'll read 10 irrelevant lines from a file", same random changes etc.

I'm not familiar with any form of intelligence that does not suffer from a bloated context. If you want to try and improve your workflow, a good place to start is using sub-agents so individual task implementations do not fill up your top level agents context. I used to regularly have to compact and clear, but since using sub-agents for most direct tasks, I hardly do anymore.