Cursor's benchmark finds that Cursor's model (Composer 2.5) is basically as good as Opus 4.8 max and GPT-5.5 xhigh, but at a fraction of the price.
Artificial Analysis' testing shows Composer 2.5 to be pretty far behind: https://artificialanalysis.ai/agents/coding-agents. You look at the DeepSWE benchmark (which is probably the hardest to game at this point) and GPT-5.5 xhigh gets a 64, Opus 4.8 max gets 56, and Cursor 2.5 gets 16.
I don't doubt that Cursor works well for some people. It's beating DeepSeek v4 Pro in the DeepSWE benchmark and that's a very capable model. But I'm skeptical of the claims that it's a competitor for Opus 4.8 and GPT-5.5. It just seems convenient that their model does so well on their own benchmark while third party benchmarks have it far behind. Maybe it's a really great benchmark and a better measure than third party ones - I'd love for a cheap model to do as well as the expensive ones.
(I work at Cursor) When Composer 2.5 launched, we initially scored very competitively on AA's composite benchmark. I believe 3rd place overall. They have recently updated to use DeepSWE, which has more of a focus on very long-horizon tasks, and Composer isn't as good at those yet. We're aware and working on this for our next model.
Overall, some benchmarks show Composer doing well, others not so much. We think the model is very capable at the given price point. There's lots to improve! If you see any specific behaviors or places the model isn't very good, lmk here or can email me lrobinson at cursor.com.
> We think the model is very capable at the given price point.
The "price point" comparison is a lie though because Composer is only available with a monthly Cursor subscription, and Cursor's external-model-per-token charges for other models are not representative of what other models' monthly subscribers get. An OpenAI $200 subscription gets you at least as much GPT 5.5 as a $200 Cursor subscription gets you Composer 2.5.
How does it compare to a $100 Claude subscription at $60? Especially in terms of how much of it I can use, because I havent found anything that is in the US that can get me similar usage as Claude at $100 per month or less, really open to alternatives.
Grok build only gave me roughly 10 hours of use for $40 for the entire month...
I don't even care about long horizon, can I use it a reasonable amount of time through the month? I use AI for hobby projects, Claude gets me quite far, but I tire of dropping $100 every month. I'm not sending my money to some Chinese firm that now has access to my computer.
Even with the new benchmark, Composer 2.5 seems to be just a bit worse than Opus 4.7. So I assume it's going to be about similar with Sonnet 5.0 at 1/6 of the cost.
Not hard to understand what's going on here. They RL'd around patterns in their data and specific capabilities, so of course they'd construct a benchmark that's aligned with the training set.
Ironically, their benchmark might be more accurate than artificial analysis for a narrow slice of things that Cursor's Eigencustomer is really interested in. Otherwise I'd take it as just another data point.
(I work at Cursor) CursorBench includes many evals from actual engineering tasks from the Cursor team, which include our private codebase. This codebase is held-out from training so models haven't seen it, including Composer.
DeepSWE is slightly flawed in the sense that is uses only its own harness and that causes issues on models that are not correctly supported by it. There's huge amount of evidence that the harness plays a big role in how these models work and yet DeepSWE entirely removes that (and has probably only tested that it works fine with some favourite model of them).
There's also issues with cost calculation (as that harness doesn't use caches) and so on as reported on their github issues.
None of the benchmarks are perfect, but that does explain a lot of the variations between benchmarks.
I think DeepSWE is flawed in a different way: the tasks look like someone took a bunch of big highly technical PRs they found really well done, and inverted it into specs for agents to autistically execute. This is not really how people use agents in practice IMO. And it's why DeepSWE is so generous to OAI models, rigid task execution is the thing they're best at. I think FrontierCode matches the vibes a lot better.
Anecdotally, I find Composer 2.5 to be useless. I do use light LLMs like Claude Haiku and some of Cursor's older free models, but Composer is negative productivity for me.
Same here, maybe I'm underusing it a bit, because for anything that is a bit more complex i tend to err on the safe side and go with anthropic, but i wonder if thats just a placebo effect because i pay more for it.
I do feel that they've really upped their game with composer this year though.
For lighter interactive agentic coding, where you type stuff into an IDE and a minute or three later get results back for review, composer 2.5 is honestly pretty great. The results get notably worse for larger tasks though.
Agreed. It’s worse than Opus of course. But Opus takes more than 10x longer to give you something to look at. I’m not kidding, I “benchmarked” a real ticket I was working on. Opus 4.7 took more than 30min. Opus 4.8 took over an hour. Composer 2.5 took 5min on the exact same prompt & local setup. My subjective review is that composer’s code was only like 10-20% worse. It still worked, it was just a bit less clean and a little more hacky. But it’s not like Opus is flawless either. At the end of the day, if it takes an hour to get to draft code I can look at and iterate on… that’s fucking impossible for me. Unless it did an excellent job. But as long as I still need to review and follow up with changes, Opus is just too slow. It’s really frustrating because it’s a lot slower than it was 6mo ago, and not noticeably better. Fable seems a step in the right direction but is $$$$
that benchmark seems to match my experience. GPT 5.5 is significantly better than Opus 4.8, last time I tried composer 2.5 it was truly dumb, and Fable to me looks to be on par with GPT 5.5 but .. different overall ... The best is to have a LLM-peer-review between GPT and Opus (now Fable) for best outcome.
Composer writes the worst, stupidest, most naive and straight up brains-dead code you could imagine. Fast and cheap is about all it’s got going for it. I mostly use it for “sort these lines alphabetically” and stuff that’s a smidge too complex for regex find/replace.
I primarily use composer. I wanted to build something from scratch recently and, thinking I was missing out on something, I got Opus to build it. I wasn't blown away. I gave the same prompts to composer and the code it came up with different but similar in quality. I ended up progressing with the composer code because it was easier to progress with improvements due to its faster response time.
I'm pretty baffled by their choice of axes. I would have thought that the left was the cheapest, not the most expensive. I appreciate that this layout means that top right can be best, but it's still unintuitive to have this backwards cost axis IMO.
Putting that aside, I spend all day every day implementing very, very hard things right on the edge of what agents are (barely, sometimes) capable of, and I have had to keep Opus on max for things that need 'real validation' for a while now. And that has felt like 'the only way' to get Opus to perform even close to 5.5 xhigh. I'm only using Opus at all because GPT-5.5 in the subscriptions only has a small (400k, but 258k effective) context window.
The difference is that 5.5 xhigh is extremely fast in most practical cases, both efficiently implementing _overall_, and responding very quickly with great adaptive thinking if you ask it something that it doesn't have to think about. Opus 4.8 Max will needlessly chew on everything and can take hours to implement even simple things, so I can mostly only use it for planning/review.
Fable is much much better at adaptive thinking / responding quickly (although probably still worse than 5.5 xhigh), and... I think folks have said enough elsewhere about its strengths and weaknesses. Sadly still not a reliable implementor for my hard tasks though (that's still GPT's domain) – it tends to leave big, dangerous holes hiding inside implementations unless babied.
Most interesting things in software engineering are (laughably) subjective.
Just check out any conversation on dynamic vs static typing, talk to a Rust zealot, or ask a backend engineer if microservices were a mistake.
It's unfortunate, and it makes it hard to have proper discussions on these subjects. It would be worthwhile to figure out how we can have more constructive arguments.
Frankly, it feels like we should just sidestep arguments entirely and just all contribute our messy data/reports, and then see how we can meld all of it together, to find the best answers for our individual situations.
Probably a good use of frontier AI, melding all of that!
It's all closed code, so I don't have a great way of showing you, but this is all pretty easy to test for yourself, and a good chunk of it is fairly objective:
On performance: just grab CC + Codex and try Opus 4.8 xhigh and GPT 5.5 xhigh side by side. Ask them a trivial question about something that's already in their context. Opus will churn for 30 seconds, and GPT 5.5 will respond in about three seconds. If you try the same with Fable 5 you'll notice way better adaptive thinking than Opus (it'll quicker than Opus, even on xhigh – although often still slower than 5.5).
I have many, many times done 'Opus xhigh, Opus max and GPT xhigh all tried to implement something' – Opus max is... hours and hours. Opus xhigh is usually ~1.5-2x GPT 5.5 xhigh. This feels like a pretty straightforward generalization of the first point. Again, just try racing three agents and see what you get.
As far as 'right on the edge of what they're able to do', my specific tasks don't matter. Just find something that no matter how hard you try, with however many agents or combinations thereof, with arbitrarily detailed plans, agents can't seem to implement without massively mistakes or a hollowing-out of 'the point' of the implementation... and then try it on the 'following generation' of models. I've been doing this repeatedly with coding agents since I turned aider into a CC-like coding agent in early 2025 (this was my second one, my first modern-style coding agent was in Jan 2025): https://github.com/Aider-AI/aider/pull/3781
A couple of examples of the latter thing that I tend to work on are database internals (indexes, query planner stuff, etc.; I built the DB in full before agents, it just works on it with me), very advanced UIs (try making a beautiful Rolex-like interactive visualization of the internals of a mechanical watch with Opus and see how far it gets – not very), and 'hardcore product questions' (all agents kinda suck at schema – Fable far less than prior ones).
I have dozens and dozens of these that they can't do, though.
A brainwave: perhaps GLM or DeepSeek could be integrated into the mix for the purposes of red-teaming the code. Fable has been blinded to security by design[0], and the open models are pretty decent at it.
[0] It's not clear what the situation with GPT-5.6 will be but the blog suggests similarly over-cautious safety filters.
Amusingly the posts for recent Opus releases brag that they successfully made it worse at security! "during its [Opus 4.7] training we experimented with efforts to differentially reduce these ["cyber"] capabilities"
I definitely use GPT-5.5 as a counterpart to validate these exact sorts of things in Anthropic models' implementations, in the (now-rarer) cases where I allow Anthropic's models _to_ implement.
And yeah, it's a bit depressing to think that 5.6 might be similarly nerfed. Less secure software for us all, I guess... except BigCorps. :(
gartner magic quadrant charts don't break the natural expectation of left-to-right, and bottom-to-top, increasing values, this charts from cursor post do.
> I'm only using Opus at all because GPT-5.5 in the subscriptions only has a small (400k, but 258k effective) context window.
Do you find that makes a difference in your work? I've been using 5.5 high/xhigh to optimize and benchmark a C codebase, and just reading the initial code virtually fills the first context window. A session will auto-compact 5-15 times, but it seems to do okay in spite of that because the task is mainly focused on the latest window each time.
I think for programming the strength of GPT over Opus is winning here over the context window.
> I think for programming the strength of GPT over Opus is winning here over the context window.
On this, absolutely!
I more often use Opus for planning than for implementation. In those cases I really do need the very large context window, because the agent has to read in a bunch of my code base and a bunch of previous plan files and product context and such, to understand what we're talking about.
And then I need to go back and forth with it over a really extended period: getting into a bunch of details, asking it to load how things already work so that we can discuss options for evolution of those, etc.
For that kind of thing, compaction completely destroys its effectiveness because even if you try to serialize out all the decisions made in the conversation into a plan file, the agent still loses e.g. the plan files and code files that it's read in that are adding sharp edges to its understanding of the scope of what's being planned.
For implementation or something like what you're describing in the vein of benchmarking, often I can get away with compaction. Although even then, if the agent needs to have a lot "loaded" into its head, to implement something very, very subtle, complex or far-reaching, in those cases it can be really detrimental if it compacts.
It's hard to believe Composer 2.5 is that good. I tried to compare it with GLM 5.2 or Opus 4.6 and it lacked thinking about the problem and critical reasoning. It's great for executing plans made by other models, but even then it does some weird code manipulation that is far from how other files around actually work.
I'm not using Cursor at the moment, but when I did (not too long ago) my experience was similar. Plan with Opus, implement with Composer, clean up with Opus.
Composer did a competent but not amazing job with a good plan. What I really liked though is it was fast! Opus could take 30 minutes to do something Composer would get done in 5-10 minutes. Of course the output wasn't perfect, but that's why I'd do a cleanup pass using Opus or Codex.
It's all a balance though, constantly changing and completely dependent on the problem you're solving. I just remain flexible and adapt my process to what's working best in the moment.
Interesting. If I may: What was this "clean up" pass? A code review? A code review with specialized prompt? A focused review to check for edge cases / logic errors / api misuse? Or, something else specific to the codebase?
In case one might not have been aware: Composer 2 was Kimi Base 2.5 post-trained (RL'd) by Cursor: https://news.ycombinator.com/item?id=48507474. Composer 2.5 might be something totally different.
I read these and think it is just the jagged edge. I do not doubt your personal experience, I have used Composer 2.5 (via Grok and the credits I get with my X premium account) the past month.
I am not building rockets, but have been quite impressed. All the models do dumb things sometimes, it has done the work I have asked it to pretty well though and has done to me some impressive work.
It is fast on Grok, for other models I have worked extensively with I think it is better than gemini 3.1 (3.5 and antigravity for me is worse than the prior gemini cli). And is comparable to Opus 4.6. (Have not used the more recent models in Claude Code.)
Interesting that Opus 4.7 does better than 4.8. Too bad they didn't test 4.6, too. I witnessed a man here mocked yesterday for insisting it was better than its successors!
Although, the benchies are always tricksy ... On DeepSWE, GPT-5.5 beats Opus-4.8, by a fair margin, but on FrontierCode, the situation is the other way around.
The only benchmark you can trust is your actual workload!
everytime a new benchmark appears, Chinese models are far lower than the level where they are supposed to be according to existing benchmarks. then after a while they recover :)
I wish all these sites would show pareto frontier graphs of cost/performance. That's the main 2 things that matter (I guess you could make it 3D with a speed param as well). https://paraplouis.github.io/llm-pareto-frontier/ is the best of these graphs I've seen but it doesn't update as frequently as I'd like.
That site is useless though because thinking tokens (and caching) and the efficiency thereof aren't accounted for. GLM5.2 is promoted by every 50 Cent Party the PLA can muster on the internet but it falls short because of its extremely verbose thinking. Anthropic models have the same problem but starting from a much higher base of real intelligence.
Which is exactly why every credible comparison now represents cost associated with completing a task, not arbitrary input and output token costs.
I've used both Composer 2.5 and GPT 5.5 (both in Cursor and in Codex) extensively, and their claim that Composer 2.5 is anywhere close in performance to GPT 5.5 is absolutely farcical. It's faster, but it's nowhere near as good.
And given that you can only use Composer with a Cursor monthly subscription, cost comparisons are pointless since an equivalently priced OpenAI subscription gets you just as much usage of the better model.
Cursor’s model excels at Cursor’s benchmark; news at 11.
The other models however are reasonably where I’d expect them to be from experience piloting all of them. Fable is outclassing everything at most things at 10x the cost, but sometimes it isn’t a choice between cheap and expensive, but expensive and possible; I’ll need to learn where that boundary is just as it was the case with other models.
gp's argument is that cheapness is a construct, derived from the real, and natural, cost parameter which most people are naturally accustomed to interpreting as increasing from left to right. cheapness would then replace the cost label, and feel natural. alas, this is not what we have here.
Do these benchmarks even add any value at this point? This one is basically Cursor saying that their model is as good as the frontier ones at a fraction of the price. The independent benchmarks are probably part of training data now and the models are pattern-matching against them all the time. The final test of a model (and the harness, probably) is how good it works FOR YOU - since most of the models can pretty much do most of our tasks on a daily basis - it boils down to which one has the least friction to its usage.
Why would anyone take this benchmark seriously? Cursor is obviously biased here. They can design it and its presentation however they want to tell the story they want to tell.
(I work at Cursor) We score well on Terminal-Bench and SWE-bench Multilingual. DeepSWE, not so great yet, as it's more for very long-horizon tasks. We're planning to include more public benchmarks in our next model release.
It's my daily driver, it's fast affordable and with a bit of guidance gets the job done.
I only reach for Claud when i need to plan something big or want to have a sparring partner to fire of some ideas.
I think what a lot of people don't realize is that you don't need a fronteer model for 80% of coding tasks. Composer 2.5 is often more than good enough, less token hungry and way faster
When you normalise for time and money, Composer 2.5 is way, way, way, way better than anything else out there. Yes it requires more babysitting, but that's a good thing.
It's surprising usable and cheap enough to run in 'fast' mode when vibing something quick. For simple code I find I prefer the code it writes over GLM or Gemini family.
I feel like this benchmark reiterates my disbelief that anyone uses the latest Anthropic models for any productive work. They seem to be the best at burning tokens and spawning unnecessary subagents even for well-defined and tightly scoped tasks.
Can we get a count of people that have had Claude read irrelevant documents or perform unnecessary web searches even when told not to from the beginning?
I'm starting to wonder if this increased token usage is inadvertently bleeding into how Anthropic actually trains their model, especially leading up to IPO. As older models are deprecated and users are forced onto newer models, if the default is less efficient and more token expensive that directly results in higher "profit" for Anthropic in terms of the consumption their users have to tolerate - lest they jump to a competitor.
I've had no problems like the ones you've mentioned while using Opus 4.8. It does overthink stuff with higher effort levels but that's kind of expected.
> I feel like this benchmark reiterates my disbelief that anyone uses the latest Anthropic models for any productive work. They seem to be the best at burning tokens and spawning unnecessary subagents even for well-defined and tightly scoped tasks.
I keep Claude around for some specific tasks:
- Linked up to Figma MCP to implement front-end stuff
- Data analysis, in the "Connect AI to a data source and ask questions" way. I've tried both Opus 4.8 high and GPT 5.5 high for this and Opus is stronger because it gets the intent in the question better
I used to keep it around for planning too, but the 4.8 plans have had more holes than swiss cheese.
Now that enterprise customers are pay-as-you-go with tokens I suspect we'll see renewed interest in OpenAI and their focus on token efficiency. At least I hope so if the alternative is abandoning the tools entirely.
I'm a bit skeptical.
Cursor's benchmark finds that Cursor's model (Composer 2.5) is basically as good as Opus 4.8 max and GPT-5.5 xhigh, but at a fraction of the price.
Artificial Analysis' testing shows Composer 2.5 to be pretty far behind: https://artificialanalysis.ai/agents/coding-agents. You look at the DeepSWE benchmark (which is probably the hardest to game at this point) and GPT-5.5 xhigh gets a 64, Opus 4.8 max gets 56, and Cursor 2.5 gets 16.
I don't doubt that Cursor works well for some people. It's beating DeepSeek v4 Pro in the DeepSWE benchmark and that's a very capable model. But I'm skeptical of the claims that it's a competitor for Opus 4.8 and GPT-5.5. It just seems convenient that their model does so well on their own benchmark while third party benchmarks have it far behind. Maybe it's a really great benchmark and a better measure than third party ones - I'd love for a cheap model to do as well as the expensive ones.
(I work at Cursor) When Composer 2.5 launched, we initially scored very competitively on AA's composite benchmark. I believe 3rd place overall. They have recently updated to use DeepSWE, which has more of a focus on very long-horizon tasks, and Composer isn't as good at those yet. We're aware and working on this for our next model.
Overall, some benchmarks show Composer doing well, others not so much. We think the model is very capable at the given price point. There's lots to improve! If you see any specific behaviors or places the model isn't very good, lmk here or can email me lrobinson at cursor.com.
> We think the model is very capable at the given price point.
The "price point" comparison is a lie though because Composer is only available with a monthly Cursor subscription, and Cursor's external-model-per-token charges for other models are not representative of what other models' monthly subscribers get. An OpenAI $200 subscription gets you at least as much GPT 5.5 as a $200 Cursor subscription gets you Composer 2.5.
How does it compare to a $100 Claude subscription at $60? Especially in terms of how much of it I can use, because I havent found anything that is in the US that can get me similar usage as Claude at $100 per month or less, really open to alternatives.
Grok build only gave me roughly 10 hours of use for $40 for the entire month...
I don't even care about long horizon, can I use it a reasonable amount of time through the month? I use AI for hobby projects, Claude gets me quite far, but I tire of dropping $100 every month. I'm not sending my money to some Chinese firm that now has access to my computer.
I never run long horizon tasks. So Composer 2.5 is great.
Even with the new benchmark, Composer 2.5 seems to be just a bit worse than Opus 4.7. So I assume it's going to be about similar with Sonnet 5.0 at 1/6 of the cost.
Don't lie. You forked a Chinese model.
Not hard to understand what's going on here. They RL'd around patterns in their data and specific capabilities, so of course they'd construct a benchmark that's aligned with the training set.
Ironically, their benchmark might be more accurate than artificial analysis for a narrow slice of things that Cursor's Eigencustomer is really interested in. Otherwise I'd take it as just another data point.
(I work at Cursor) CursorBench includes many evals from actual engineering tasks from the Cursor team, which include our private codebase. This codebase is held-out from training so models haven't seen it, including Composer.
DeepSWE is slightly flawed in the sense that is uses only its own harness and that causes issues on models that are not correctly supported by it. There's huge amount of evidence that the harness plays a big role in how these models work and yet DeepSWE entirely removes that (and has probably only tested that it works fine with some favourite model of them).
There's also issues with cost calculation (as that harness doesn't use caches) and so on as reported on their github issues.
None of the benchmarks are perfect, but that does explain a lot of the variations between benchmarks.
I think DeepSWE is flawed in a different way: the tasks look like someone took a bunch of big highly technical PRs they found really well done, and inverted it into specs for agents to autistically execute. This is not really how people use agents in practice IMO. And it's why DeepSWE is so generous to OAI models, rigid task execution is the thing they're best at. I think FrontierCode matches the vibes a lot better.
Naturally, given it’s their benchmark they have overfitted their model somewhat to it.
Cursor sessions are pretty much what composer models are RL'd on. This bench and the training data are/should be basically the same distribution.
Anecdotally, I find Composer 2.5 to be useless. I do use light LLMs like Claude Haiku and some of Cursor's older free models, but Composer is negative productivity for me.
The opposite , I use for everything like trigger and monitor a 10 steps release process using composer , a very capable model
this is my finding too, i have moved to it fully for most of the plan/coding.
for most tasks is capable and very cheap, for a days worth of tasks is costing about $10
Same here, maybe I'm underusing it a bit, because for anything that is a bit more complex i tend to err on the safe side and go with anthropic, but i wonder if thats just a placebo effect because i pay more for it.
I do feel that they've really upped their game with composer this year though.
For lighter interactive agentic coding, where you type stuff into an IDE and a minute or three later get results back for review, composer 2.5 is honestly pretty great. The results get notably worse for larger tasks though.
Agreed. It’s worse than Opus of course. But Opus takes more than 10x longer to give you something to look at. I’m not kidding, I “benchmarked” a real ticket I was working on. Opus 4.7 took more than 30min. Opus 4.8 took over an hour. Composer 2.5 took 5min on the exact same prompt & local setup. My subjective review is that composer’s code was only like 10-20% worse. It still worked, it was just a bit less clean and a little more hacky. But it’s not like Opus is flawless either. At the end of the day, if it takes an hour to get to draft code I can look at and iterate on… that’s fucking impossible for me. Unless it did an excellent job. But as long as I still need to review and follow up with changes, Opus is just too slow. It’s really frustrating because it’s a lot slower than it was 6mo ago, and not noticeably better. Fable seems a step in the right direction but is $$$$
that benchmark seems to match my experience. GPT 5.5 is significantly better than Opus 4.8, last time I tried composer 2.5 it was truly dumb, and Fable to me looks to be on par with GPT 5.5 but .. different overall ... The best is to have a LLM-peer-review between GPT and Opus (now Fable) for best outcome.
Composer writes the worst, stupidest, most naive and straight up brains-dead code you could imagine. Fast and cheap is about all it’s got going for it. I mostly use it for “sort these lines alphabetically” and stuff that’s a smidge too complex for regex find/replace.
I primarily use composer. I wanted to build something from scratch recently and, thinking I was missing out on something, I got Opus to build it. I wasn't blown away. I gave the same prompts to composer and the code it came up with different but similar in quality. I ended up progressing with the composer code because it was easier to progress with improvements due to its faster response time.
By the same token, Fable 5 is given a score of 77 vs 76 for GPT 5.5
I mean, they train their model on their training data. So by it should score well on their own benchmark.
I'm pretty baffled by their choice of axes. I would have thought that the left was the cheapest, not the most expensive. I appreciate that this layout means that top right can be best, but it's still unintuitive to have this backwards cost axis IMO.
Putting that aside, I spend all day every day implementing very, very hard things right on the edge of what agents are (barely, sometimes) capable of, and I have had to keep Opus on max for things that need 'real validation' for a while now. And that has felt like 'the only way' to get Opus to perform even close to 5.5 xhigh. I'm only using Opus at all because GPT-5.5 in the subscriptions only has a small (400k, but 258k effective) context window.
The difference is that 5.5 xhigh is extremely fast in most practical cases, both efficiently implementing _overall_, and responding very quickly with great adaptive thinking if you ask it something that it doesn't have to think about. Opus 4.8 Max will needlessly chew on everything and can take hours to implement even simple things, so I can mostly only use it for planning/review.
Fable is much much better at adaptive thinking / responding quickly (although probably still worse than 5.5 xhigh), and... I think folks have said enough elsewhere about its strengths and weaknesses. Sadly still not a reliable implementor for my hard tasks though (that's still GPT's domain) – it tends to leave big, dangerous holes hiding inside implementations unless babied.
>Putting that aside, I spend all day every day implementing very, very hard things right on the edge of what agents are (barely, sometimes) capable of
Is a single thing in your post demonstrable, or are we just supposed to take your word for it? Because all of this stuff sounds laughably subjective.
Most interesting things in software engineering are (laughably) subjective.
Just check out any conversation on dynamic vs static typing, talk to a Rust zealot, or ask a backend engineer if microservices were a mistake.
It's unfortunate, and it makes it hard to have proper discussions on these subjects. It would be worthwhile to figure out how we can have more constructive arguments.
"Have you ever noticed that anybody driving slower than you is an idiot, and anyone going faster than you is a maniac?" -- George Carlin
Thanks very much for saying this!
Frankly, it feels like we should just sidestep arguments entirely and just all contribute our messy data/reports, and then see how we can meld all of it together, to find the best answers for our individual situations.
Probably a good use of frontier AI, melding all of that!
It's all closed code, so I don't have a great way of showing you, but this is all pretty easy to test for yourself, and a good chunk of it is fairly objective:
On performance: just grab CC + Codex and try Opus 4.8 xhigh and GPT 5.5 xhigh side by side. Ask them a trivial question about something that's already in their context. Opus will churn for 30 seconds, and GPT 5.5 will respond in about three seconds. If you try the same with Fable 5 you'll notice way better adaptive thinking than Opus (it'll quicker than Opus, even on xhigh – although often still slower than 5.5).
I have many, many times done 'Opus xhigh, Opus max and GPT xhigh all tried to implement something' – Opus max is... hours and hours. Opus xhigh is usually ~1.5-2x GPT 5.5 xhigh. This feels like a pretty straightforward generalization of the first point. Again, just try racing three agents and see what you get.
As far as 'right on the edge of what they're able to do', my specific tasks don't matter. Just find something that no matter how hard you try, with however many agents or combinations thereof, with arbitrarily detailed plans, agents can't seem to implement without massively mistakes or a hollowing-out of 'the point' of the implementation... and then try it on the 'following generation' of models. I've been doing this repeatedly with coding agents since I turned aider into a CC-like coding agent in early 2025 (this was my second one, my first modern-style coding agent was in Jan 2025): https://github.com/Aider-AI/aider/pull/3781
A couple of examples of the latter thing that I tend to work on are database internals (indexes, query planner stuff, etc.; I built the DB in full before agents, it just works on it with me), very advanced UIs (try making a beautiful Rolex-like interactive visualization of the internals of a mechanical watch with Opus and see how far it gets – not very), and 'hardcore product questions' (all agents kinda suck at schema – Fable far less than prior ones). I have dozens and dozens of these that they can't do, though.
>it tends to leave big, dangerous holes hiding inside implementations unless babied.
A brainwave: perhaps GLM or DeepSeek could be integrated into the mix for the purposes of red-teaming the code. Fable has been blinded to security by design[0], and the open models are pretty decent at it.
[0] It's not clear what the situation with GPT-5.6 will be but the blog suggests similarly over-cautious safety filters.
Amusingly the posts for recent Opus releases brag that they successfully made it worse at security! "during its [Opus 4.7] training we experimented with efforts to differentially reduce these ["cyber"] capabilities"
I definitely use GPT-5.5 as a counterpart to validate these exact sorts of things in Anthropic models' implementations, in the (now-rarer) cases where I allow Anthropic's models _to_ implement.
And yeah, it's a bit depressing to think that 5.6 might be similarly nerfed. Less secure software for us all, I guess... except BigCorps. :(
It’s Gartner. Top-right is where you want to be.
gartner magic quadrant charts don't break the natural expectation of left-to-right, and bottom-to-top, increasing values, this charts from cursor post do.
Sounds like you're in the Trough of Disillusionment.
> I'm only using Opus at all because GPT-5.5 in the subscriptions only has a small (400k, but 258k effective) context window.
Do you find that makes a difference in your work? I've been using 5.5 high/xhigh to optimize and benchmark a C codebase, and just reading the initial code virtually fills the first context window. A session will auto-compact 5-15 times, but it seems to do okay in spite of that because the task is mainly focused on the latest window each time.
I think for programming the strength of GPT over Opus is winning here over the context window.
> I think for programming the strength of GPT over Opus is winning here over the context window.
On this, absolutely!
I more often use Opus for planning than for implementation. In those cases I really do need the very large context window, because the agent has to read in a bunch of my code base and a bunch of previous plan files and product context and such, to understand what we're talking about.
And then I need to go back and forth with it over a really extended period: getting into a bunch of details, asking it to load how things already work so that we can discuss options for evolution of those, etc.
For that kind of thing, compaction completely destroys its effectiveness because even if you try to serialize out all the decisions made in the conversation into a plan file, the agent still loses e.g. the plan files and code files that it's read in that are adding sharp edges to its understanding of the scope of what's being planned.
For implementation or something like what you're describing in the vein of benchmarking, often I can get away with compaction. Although even then, if the agent needs to have a lot "loaded" into its head, to implement something very, very subtle, complex or far-reaching, in those cases it can be really detrimental if it compacts.
> I'm pretty baffled by their choice of axes
To put their own model out in front?
I agree why they reverse the x axis makes this graph very hard to understand for the casual observer.
You can set GPT 5.5 to 1M context mode in Cursor but it costs more after the default 272k.
Yeah I've done this, it's just unaffordably/impractically expensive compared to the official subscriptions :/
opus@max is on average worst than opux@xhigh
for supporting evidence, see first chart here: https://www.anthropic.com/news/claude-fable-5-mythos-5
It's hard to believe Composer 2.5 is that good. I tried to compare it with GLM 5.2 or Opus 4.6 and it lacked thinking about the problem and critical reasoning. It's great for executing plans made by other models, but even then it does some weird code manipulation that is far from how other files around actually work.
I'm not using Cursor at the moment, but when I did (not too long ago) my experience was similar. Plan with Opus, implement with Composer, clean up with Opus.
Composer did a competent but not amazing job with a good plan. What I really liked though is it was fast! Opus could take 30 minutes to do something Composer would get done in 5-10 minutes. Of course the output wasn't perfect, but that's why I'd do a cleanup pass using Opus or Codex.
It's all a balance though, constantly changing and completely dependent on the problem you're solving. I just remain flexible and adapt my process to what's working best in the moment.
Interesting. If I may: What was this "clean up" pass? A code review? A code review with specialized prompt? A focused review to check for edge cases / logic errors / api misuse? Or, something else specific to the codebase?
In case one might not have been aware: Composer 2 was Kimi Base 2.5 post-trained (RL'd) by Cursor: https://news.ycombinator.com/item?id=48507474. Composer 2.5 might be something totally different.
I read these and think it is just the jagged edge. I do not doubt your personal experience, I have used Composer 2.5 (via Grok and the credits I get with my X premium account) the past month.
I am not building rockets, but have been quite impressed. All the models do dumb things sometimes, it has done the work I have asked it to pretty well though and has done to me some impressive work.
It is fast on Grok, for other models I have worked extensively with I think it is better than gemini 3.1 (3.5 and antigravity for me is worse than the prior gemini cli). And is comparable to Opus 4.6. (Have not used the more recent models in Claude Code.)
Interesting that Opus 4.7 does better than 4.8. Too bad they didn't test 4.6, too. I witnessed a man here mocked yesterday for insisting it was better than its successors!
Although, the benchies are always tricksy ... On DeepSWE, GPT-5.5 beats Opus-4.8, by a fair margin, but on FrontierCode, the situation is the other way around.
The only benchmark you can trust is your actual workload!
everytime a new benchmark appears, Chinese models are far lower than the level where they are supposed to be according to existing benchmarks. then after a while they recover :)
The magic of distillation!
I wish all these sites would show pareto frontier graphs of cost/performance. That's the main 2 things that matter (I guess you could make it 3D with a speed param as well). https://paraplouis.github.io/llm-pareto-frontier/ is the best of these graphs I've seen but it doesn't update as frequently as I'd like.
That site is useless though because thinking tokens (and caching) and the efficiency thereof aren't accounted for. GLM5.2 is promoted by every 50 Cent Party the PLA can muster on the internet but it falls short because of its extremely verbose thinking. Anthropic models have the same problem but starting from a much higher base of real intelligence.
Which is exactly why every credible comparison now represents cost associated with completing a task, not arbitrary input and output token costs.
[delayed]
The most interesting part is costs . Gpt 5.5 and sonnet 5 cost same amount of money as GLM 5.2 but are more capable models
I've used both Composer 2.5 and GPT 5.5 (both in Cursor and in Codex) extensively, and their claim that Composer 2.5 is anywhere close in performance to GPT 5.5 is absolutely farcical. It's faster, but it's nowhere near as good.
And given that you can only use Composer with a Cursor monthly subscription, cost comparisons are pointless since an equivalently priced OpenAI subscription gets you just as much usage of the better model.
Cursor’s model excels at Cursor’s benchmark; news at 11.
The other models however are reasonably where I’d expect them to be from experience piloting all of them. Fable is outclassing everything at most things at 10x the cost, but sometimes it isn’t a choice between cheap and expensive, but expensive and possible; I’ll need to learn where that boundary is just as it was the case with other models.
I like Composer a lot as a general-purpose workhorse, but putting it over gpt5.5 medium makes the whole graph lose trust to me, asme witg GLM so low
backwards X axis? is there a reason for that? it looks ridiculous
It looks very natural, cheaper is better after all. Performance axis going up, and cheapness axis going up match each other.
gp's argument is that cheapness is a construct, derived from the real, and natural, cost parameter which most people are naturally accustomed to interpreting as increasing from left to right. cheapness would then replace the cost label, and feel natural. alas, this is not what we have here.
This seems to be a common choice with AI industry graphs, to give you that “upward and outward” frontier shape.
Do these benchmarks even add any value at this point? This one is basically Cursor saying that their model is as good as the frontier ones at a fraction of the price. The independent benchmarks are probably part of training data now and the models are pattern-matching against them all the time. The final test of a model (and the harness, probably) is how good it works FOR YOU - since most of the models can pretty much do most of our tasks on a daily basis - it boils down to which one has the least friction to its usage.
No shot 2.5 is beating out 4.8
Why would anyone take this benchmark seriously? Cursor is obviously biased here. They can design it and its presentation however they want to tell the story they want to tell.
Cursor: Find me another benchmark where Composer 2.5 is a top 10 frontier coding model
(I work at Cursor) We score well on Terminal-Bench and SWE-bench Multilingual. DeepSWE, not so great yet, as it's more for very long-horizon tasks. We're planning to include more public benchmarks in our next model release.
Would like to see wall times. I feel that’s the part that annoys me most, my tasks aren’t particularly challenging I want them done fast
insert obama medal meme
is composer 2.5 that good at that pricepoint? Seems like the gemini flash playbook of trying to get most bang for the buck.
It's my daily driver, it's fast affordable and with a bit of guidance gets the job done.
I only reach for Claud when i need to plan something big or want to have a sparring partner to fire of some ideas.
I think what a lot of people don't realize is that you don't need a fronteer model for 80% of coding tasks. Composer 2.5 is often more than good enough, less token hungry and way faster
I have been doing the same for quite a while now. Composer 2.5 is incredible when you’re working in the loop.
When you normalise for time and money, Composer 2.5 is way, way, way, way better than anything else out there. Yes it requires more babysitting, but that's a good thing.
It's surprising usable and cheap enough to run in 'fast' mode when vibing something quick. For simple code I find I prefer the code it writes over GLM or Gemini family.
It’s fast and affordable.
yes, its very good.
I feel like this benchmark reiterates my disbelief that anyone uses the latest Anthropic models for any productive work. They seem to be the best at burning tokens and spawning unnecessary subagents even for well-defined and tightly scoped tasks.
Can we get a count of people that have had Claude read irrelevant documents or perform unnecessary web searches even when told not to from the beginning?
I'm starting to wonder if this increased token usage is inadvertently bleeding into how Anthropic actually trains their model, especially leading up to IPO. As older models are deprecated and users are forced onto newer models, if the default is less efficient and more token expensive that directly results in higher "profit" for Anthropic in terms of the consumption their users have to tolerate - lest they jump to a competitor.
I've had no problems like the ones you've mentioned while using Opus 4.8. It does overthink stuff with higher effort levels but that's kind of expected.
Same (including the overthinking issue).
> I feel like this benchmark reiterates my disbelief that anyone uses the latest Anthropic models for any productive work. They seem to be the best at burning tokens and spawning unnecessary subagents even for well-defined and tightly scoped tasks.
I keep Claude around for some specific tasks:
- Linked up to Figma MCP to implement front-end stuff
- Data analysis, in the "Connect AI to a data source and ask questions" way. I've tried both Opus 4.8 high and GPT 5.5 high for this and Opus is stronger because it gets the intent in the question better
I used to keep it around for planning too, but the 4.8 plans have had more holes than swiss cheese.
Now that enterprise customers are pay-as-you-go with tokens I suspect we'll see renewed interest in OpenAI and their focus on token efficiency. At least I hope so if the alternative is abandoning the tools entirely.
> I'm starting to wonder if this increased token usage is inadvertently bleeding into how Anthropic actually trains their model
Related: Sonnet 5’s new tokenizer increases token usage by 30%. (https://simonwillison.net/2026/Jun/30/claude-sonnet-5/)