Leanstral 1.5

(docs.mistral.ai)

228 points | by vetronauta 13 hours ago

14 comments

  • Grimblewald 5 hours ago
    Got curious, sign up, add money to account, try to use. Can't, it's a labs model. Fine, let's enable labs. Can't, unspecified error. Fine, lets contact customer support as instructed, can't no customer support, just a half-assed FAQ, that seems vibe-coded and searched poorly, totally irrelevant answers coming up for all queries tried. Then it hit me:

    If AI makes good customer support, then why does no AI company use theirs to provide customer support?

    • thih9 11 minutes ago
      > If AI makes good customer support, then why does no AI company use theirs to provide customer support?

      They do! E.g. Cursor. See earlier discussions like "Cursor IDE support hallucinates lockout policy, causes user cancellations"[1].

      [1]: https://news.ycombinator.com/item?id=43683012

    • saghm 4 hours ago
      No one ever thought it made good customer support. It makes cheap customer support, and quite a lot of companies already have shitty customer support because they don't care about it being good, so they're thrilled to get to cut costs further.

      It's "good" from the perspective of a company that's annoyed to have to spend money on actually fixing things.

    • blueTiger33 3 minutes ago
      they are working on LeChaton fat
    • puppymaster 1 hour ago
      I laughed and cried at this comment. It's so uncannily EU. Just spent 18 months landing an EU enterprise contract. Signed today and sent it back and got an automated message 'sorry will be on vacation til end of July...' This is the fourth vacation emails I got since corresponding with this contact window for the past 1 year.
      • throw1234567891 37 minutes ago
        Yes, we have more vacation in the EU than people in the US.
        • roysting 8 minutes ago
          You would think Europeans would be masters of continuity than. But no, usually it is a form of narcissism and selfishness that is utterly indifferent to the needs of others that just says “oh well, I guess you’ll have to just wait for me to get back from my vacation and on my terms to continue on with your life”.

          It’s a common disgusting mentality wide spread across Europe.

      • embedding-shape 21 minutes ago
        How is people having reasonable work place environments related to shit customer support and companies trying to optimize for reducing costs? Seems highly unrelated.
    • begleri 2 hours ago
      That's frustrating and odd because I can use the model for free (have never connected any form of payment)
    • criticalfault 4 hours ago
      These guys don't answer emails. Same for qwant.

      Sample of two, but I'm assuming french companies don't like to being contacted n English.

      • MrToadMan 3 hours ago
        If only they had access to a world class translation system, they could auto translate between languages effortlessly :)
        • GTP 1 hour ago
          They're just offended by people not using their product :D
      • zelphirkalt 26 minutes ago
        Wasn't there a thread recently, about them disappointingly being also just a US company, just with an office in France?
    • roysting 27 minutes ago
      Mostly political, economic, and social ramifications.
    • Mashimo 4 hours ago
      Further down someone said the support is great and they respond within the day.
    • gregman1 3 hours ago
      “Don’t get high on your own supply” - I think it’s Microsoft’s motto.
    • tmikaeld 4 hours ago
      This isn’t the first time. I’m amazed at how they manage to fumble releases over and over …
    • adithyassekhar 5 hours ago
      Because that AI will either expose their business or it will be so nerfed it’s useless.
  • ramon156 1 hour ago
  • helloplanets 2 hours ago
    Tangential, but I'm pretty sad about EU having absolutely nothing in the actual SotA LLM market. Especially given the recent events of US completely restricting the actual SotA models.

    Has this been just pure lack of funding and infra?

    • mike_hearn 16 minutes ago
      Mistral has raised $4B+ which is a decent chunk of change, albeit not in the league of OpenAI/Anthropic/xAI.

      The hard part is justifying pure LLM development financially. Models are all very similar. OpenAI justified it originally by being a 'charity' dedicated to pure research (not financial). Anthropic justified it by saying OpenAI didn't care enough about safety and splitting from them (not financial). Elon justified it by saying that AI would be woke and untruthful unless he built Grok (not financial). Google did Gemini because, well, they're where it all started and because AI research was one of the core missions Larry & Sergey gave it when they started it (but then sat on it for financial reasons).

      Then there's the Chinese models. It's unclear what their motives are tbh. I've never seen a really great explanation, only hypotheses. But as they're giving them away for free or very underpriced, their motivation doesn't seem to be financial either.

      But Mistral is a normal company. It doesn't have rich backers giving it money based on narratives about cosmic destiny, so it needs to justify what it's doing with ROI. So that more or less rules out large scale LLM training.

      There's also EU regulation to consider. When I looked at this in the past I found lots of odd rules that kill off any chance of having a European tech industry. The UK had one that said you could only crawl the internet for research purposes! And without the First Amendment you're at much greater risk of being prosecuted for things your models say. See how Germany has taken Google to court over things its models put in its search result pages.

      So the benefit isn't clear and the legal risks are very high.

    • Sol- 1 hour ago
      The EU simply doesn't have a proper common market, especially when it comes to capital. Having more people than the US and a big economy in aggregate doesn't matter much if you can't efficiently pool resources. Could we in Europe have 100 billion fundraises for a new lab? If not, then it's over and you can give up.
      • Epa095 43 minutes ago
        I agree with your analysis, at least as long as we shall remain strictly inside the free market methodologies. And having a common capital market would be good no matter what.

        But there are other ways to pool resources than the free market. Airbus was not made dynamically in a market, neither was the LHC. 100 billion € is a lot, it's half of the total allocated aid from Europe to Ukraina. Which can be read in two ways, either 'helping Ukraine is already weighing us down, another similar cost is too much for some IT toy ', or 'Europe has the ability to collect massive amount of capital when it needs to, and AI is a existential threat which justifies it'.

    • Epa095 1 hour ago
      Software in general, AI as well, is a rich get richer market. The big American companies can afford to (and very much do) scoop up European talents and upcoming European companies. And if they don't want to buy them, they can undercut them to bankruptcy. We live in a colony economy, with human capital as the raw produce, and it all gets funneled to the USA.

      The only way to avoid this is to stop playing the game as it is today, and start using proper industrial policy to build up a competitive industry (like China did). There has been no appetite for that the last decades, but Trump is making it completely clear that the state is back, and Europe is slowly acknowledging it as well.

    • vlian2088 1 hour ago
      https://en.wikipedia.org/wiki/Artificial_Intelligence_Act

      and now they get to sit in the chair in the corner and watch as its citizens use American and Chinese models.

      • yfontana 1 hour ago
        That act applies just as much to those American and Chinese models within the EU.
        • Sol- 1 hour ago
          Which is a mistake the EU makes again and again. If you put onerous requirements on everyone, this means that the most well-capitalized firms will be able to shoulder the regulatory overhead the easiest. But who can't? New European startups. This already killed part of the tech sector with the GDPR while Google and Meta just hire 100 lawyers and are done with it.
          • roblabla 10 minutes ago
            [citation needed] here. The tech sector is still well and alive in EU, and outside adtech (which was hit hard by GDPR - that was the point) doesn't seem to have been visibly impacted.
      • petesergeant 1 hour ago
        Given that American and Chinese models exist in an environment where the executive can and will pull models because the vibes are off, or they don't think a company is sufficiently deferential or politically aligned, this feels like false attribution.
    • ciefa 2 hours ago
      [dead]
  • GTP 1 hour ago
    "Page not found" for me. Did you manage to access this? What is this about?
  • henryrobbins00 6 hours ago
    What a coincidence! I just released OpenATP earlier today. OpenATP is an open-source Python package and CLI for agentic automated theorem provers. It includes support for Leanstral with Mistral’s Vibe harness. The previous production Leanstral model was deprecated on May 22nd. I will update the package to point to Leanstral 1.5 ASAP!

    GitHub: https://github.com/henryrobbins/open-atp

    Docs: https://open-atp.henryrobbins.com

  • c7b 4 hours ago
    I'm not sure I understand the Weights policy. This site says the weights are Apache-licensed, suggesting it's open weights. But I can't find a download link. Their Huggingface profile seems to only provide an earlier snapshot [0]. Any pointers on whether/where we can or will be able to download the weights?

    [0] https://huggingface.co/mistralai/Leanstral-2603

  • __natty__ 11 hours ago
    Discussion about Leanstral 1: https://news.ycombinator.com/item?id=47404796
  • butokai 1 hour ago
    I am getting 404 right now
  • pmarreck 6 hours ago
    Lean 4 and Idris 2 are underrated, and likely great for LLM's to code in (since they provide additional guarantees)
  • impodimium 6 hours ago
    Interesting that this only specialized for Lean4 and not for similar like Coq
    • DoctorOetker 6 hours ago
      I would have preferred actual proof objects, as in Metamath's: separate the actual proof from the heuristics used to find it (also valuable, but a different thing).
  • doctorpangloss 10 hours ago
    Real talk, does anyone use anything from Mistral because it performs the best, by whatever secular metric of your choosing? Or is it only used "because EU"? Just focus on answering the question. I wonder if anyone has observed it perform better on any objective metric in any rigorous setting.
    • ashenke 9 hours ago
      I use their Voxtral Mini STT audio model to automatically transcribe my podcasts into markdown. Out of all the STT models I've tried, it's both the best performing and one of the cheapest! It's really accurate, feeding the episode notes and the podcast description ensures all names are properly spelled, and speaker diarization works really great. (I just do a Gemini flash pass at the end to identify the speakers, so it shows the host name instead of "Speaker 1")
    • Confiks 9 hours ago
      For writing and languange learning it's very decent, especially Mistral Large. The pricing is very good too. I really like the consistently low time to first token and good token per second. Claude, especially in the past, would be very inconsistent, often with outages. Mistral mostly just always works and is very fast.

      Technical questions are unfortunately hit or miss. I'm lately pretty much always using a system prompt that emphasizes short answers [1], and Opus regularly one-shots it while Mistral needs a follow up. I use big-AGI as a model router [2] (dumb name, great software), which makes switching midway very easy though. For coding I'm still using Claude Code mostly out of inertia (although I really want to move to an OSS harness) and the one time I tried their `vibe` tool months ago it was a bit rough.

      Mistral TTS with diarization is also great and cheap. That's the only thing for which I use their web UI.

      [1] Give a short but helpful answer to the question the user asks. When helping with a computer-related task, unless the user asks, don't give any installation or setup instructions, but just get straight to the point. When the user asks a follow up question, give a more complete and longer answer while still not overexplaining. When the user prefaces the question with "short mode off" in any question, give a full and well considered reply.

      [2] https://github.com/enricoros/big-AGI

      • Skinney 5 hours ago
        vibe has improved _a lot_ during the past few months, fyi.

        The new Mistral Medium 3.5 is also a big improvement over devstral-2

      • BartjeD 3 hours ago
        Mistral doesn't have caching on batches. For me that meant they are 10x more expensive than Google.

        I think its dumb.

        Their support is hidden away in a chat bubble at the bottom. But they do respond promptly.

        Its decent, but after switching to Google i wouldn't go back

    • troyvit 10 hours ago
      We are not Mistral's target audience. For instance I don't know if Leanstral performs the best as a "formal proof engineering model optimised for automated theorem proving and autoformalization" because I don't even know wth that is or who else does it.

      Mistral themselves focus more on b2b; financial services, manufacturing, stuff like that, and they get some big clients that way.

      Despite not being their target, I started using them because they have many open models. I continue using them because, yeah EU, but also because the community is great and the tool makes me think more than Claude does. Last, I stick with them because they are one of the few AI companies that are up-front about their environmental impact and are actually trying to minimize it while still providing a decent product.

      • computerex 9 hours ago
        It's for mathematics. There is this programming language: https://lean-lang.org/

        If you can express a solution in Lean you can formally prove or disprove it. Formal verification is making a debut in traditional engineering toolkits.

    • istinetz 41 minutes ago
      For a defense project we're working on, we basically have a hard requirement to use european cloud provider + european llm

      We cannot use open source LLMs on-prem, I asked. So that's basically a hard requirement to use mistral, even though Chinese models are strictly better on every dimension.

    • psalaun 5 hours ago
      I use it as my workhorse for coding and general chat questions, because it's good enough 80% of the time, and indeed it's french/european (with heavy US capital tho...).

      We complain too much about not having enough major competitors in the IT space, to not support a burgeoning one even if it's less powerful than SOTA labs

      • barrenko 4 hours ago
        Well, if you're a taxpayer in EU you're already supporting it implicitly.
    • data-ottawa 10 hours ago
      Mistral medium is considerably better at writing than Opus.

      I’ve also found it very good at pulling info from pdfs. Even a complicated festival with multiple venues and timetables.

      • tjwebbnorfolk 7 hours ago
        Writing what? I found it worse than gemma4 at coding even though it's 4x the parameter size
    • anonyfox 17 minutes ago
      just used mistral for a database/scraping creation tool and ended at <10k€ in token costs (via openrouter), beating gpt5.4-mini in output quality and speed and costs after actual testing A/B fairly. so its a super scoped task to be performed hundreds of thousands of time for some automation and mistral just did it better across all dimensions that gpt-5.4-mini. of course thats not a headline in terms of frontier model competitiveness, but for "the boring parts" it just was flat out better than anything else consistently. bonus points it handles mixed-language-content with nuances surprisingly well to turn web content in the wild into structured data really good and fast.
    • trentor 10 hours ago
      I like the models for creative writing. They have a distinct voice that is different from the other llms.
      • SwellJoe 10 hours ago
        I made a game (https://prose-or-con.com) where you pick whether writing is AI or human. Mistral is a bonkers weird writer. So weird I fell for it a couple of times because I thought, "No way a model writes this weird." Not, like, incorrect grammar or spelling or anything, just...off-kilter. Kinda sassy.
        • vlian2088 6 hours ago
          needs a leaderboard of models most often mistaken for humans.
          • SwellJoe 5 hours ago
            Yes, it's on the todo list, but I need more data. Only a half dozen people have played it and submitted a score. I'm storing the hashes of passages people got right and wrong so I can make exactly that chart at some point. I think both "the most human-like AI" and "the most AI-like human" are both interesting pieces of data, but I don't know either yet.
            • vlian2088 4 hours ago
              try posting it on r/localllama and r/sillytavernai
    • adev_ 10 hours ago
      > Mistral because it performs the best, by whatever secular metric of your choosing?

      I am. I use them primarily through their vibe CLI.

      Reason is simple: They are cheaper (by almost one order of magnitude compared to Claude) and still do the job pretty well.

      For small programming tasks, quick prototyping, refactoring or anything verbose and not requiring a context too large: I first go to Mistral and then eventually to Claude if I'm unsatisfied.

      I also found out some of their models to be more responsive than OpenAI ones (which is not so surprising considering the size).

      My tasks are mainly C++ and Python programming. People in other languages might not share my enthusiasm.

      • jatora 9 hours ago
        Your reason can't be cost because there are superior models that are cheaper than Mistral models, for coding. So i re-ask the question
        • adev_ 9 hours ago
          > Your reason can't be cost because there are superior models that are cheaper than Mistral models

          Nope. This is not my experience.

          Public pricing in token/$ is only part of the equation.

          Mistral tooling to consume significantly less tokens-per-given-task than the Anthropic ones.

          My bills currently reflects that.

          • tjwebbnorfolk 7 hours ago
            I think other commenter is talking about smaller/cheaper models like Qwen that outperform mistral on just about every metric
            • adev_ 2 hours ago
              I played with Qwen few months ago, I do prefer Mistral vibe for everyday usage (significantly faster if not self hosted).
          • greenavocado 7 hours ago
            Compare to Xiaomi MiMo-V2.5 you will be shocked
    • evilmonkey19 10 hours ago
      I use it because EU and API pricing is decent to me. And support is awesome also. They reply the same day or at most the next day, and they follow the ticket great. It isn't that bad, but neither the best.
      • jatora 9 hours ago
        Why do you need support so often?
    • Adrig 10 hours ago
      A few months ago, I had some data cleaning to do; their small model was surprisingly efficient and got the job done for 0.2x what I expected to run (Anthropic Sonnet / Haiku). Their TTS / STT is also roughly at the frontier, at least for French.

      But I admit I only consider them because they're from France. Haven't seen a dimension where they're competitive for general users

    • Hamuko 5 hours ago
      >Just focus on answering the question.

      Are you trying to instruct me like an LLM?

    • hakunin 9 hours ago
      I use it because it’s a simple, convenient and cheap OCR api. Specifically via my ringbinder[1] tool.

      [1]: https://github.com/maxim/ringbinder

    • suprjami 6 hours ago
      I still prefer Mistral Nemo 12B for text summarisation tasks. It has a nice style. The Mistral Small 24B is also decent. I have a YouTube transcript summariser which I like these for.

      However these days I usually have Qwen 3.6 27B already loaded so I mostly just use that instead.

    • bee_rider 6 hours ago
      I liked that their website didn’t ask for my phone number, IIRC.
    • refulgentis 8 hours ago
      OCR is off the charts good on every metric you can think of.

      LLMs are a near-afterthought at this point if you don’t have data residency requirements. I love them and they’re slightly underrated, their models are consistently well-trained, open, but as you note, behind. There is no metric that will say they’re ahead in anything.

      • cavenditti 3 hours ago
        This. Best OCR provider by measure and it’s been for years
        • urbsgpw 1 hour ago
          Hmm, not sure I'd agree. I really like google's offering there (they suck at coding agents but their OCR is good value for money - well up till the latest flash model which has got wicked expensive). See also https://www.ocrarena.ai/leaderboard I know these leaderboards are iffy, but at least my experience has been somewhat similar.
  • esafak 9 hours ago
    Is this useful for specifying programs too or only theorems?
    • zeckalpha 9 hours ago
      Curry-Howard correspondence.
      • esafak 5 hours ago
        It may be theoretically possible, but is it ergonomic and useful? Do you use Lean for your programs?
  • mertleee 9 hours ago
    [dead]
  • beernet 2 hours ago
    This went to market horribly (if you can even call it that), just look at the comments. Mistral played themselves big time over the past ~18 months. Non-competitive products and models combined with bad marketing and GTM...Oh Europe