SpaceXAI debuts Grok 4.5, its first model built in partnership with Cursor, designed to “handle difficult, long-running tasks” across finance, legal, and coding

Bloomberg 2026-07-09 Carmen Arroyo

Context & Ripple Effects

The related coverage frames this as a deeper product tie between SpaceXAI and Cursor rather than a standalone model release. It also places Cursor at an awkward moment: the company is expanding from coding toward a broader agent while facing criticism over the reliability of AI-assisted software work.

That tension matters because the new system is aimed at work where long task chains and dependable outputs are central, including legal, finance, and software workflows. Related reporting also connects Grok to a planned GenAI.mil deployment, raising the stakes for operational reliability.

First-order effects

SpaceXAI and Cursor gain a joint flagship offering for complex knowledge-work and coding workflows, extending their partnership beyond Cursor's existing developer-focused identity.
Cursor's reliability concerns become more consequential: a model positioned for long-running tasks will be judged on consistency, verification, and failure handling, not just rapid code generation.

Second-order effects

Competing coding and workplace-agent providers will face pressure to demonstrate that their systems can sustain multi-step tasks across professional domains, rather than merely generate isolated answers or code snippets.
Organizations evaluating AI for legal, finance, or engineering work are likely to place greater weight on human review, auditability, and workflow controls, especially where unreliable AI-assisted coding has already drawn criticism.

Third-order effects

If partnerships like this prove durable, the market may shift from point AI assistants toward integrated agents that span developer tools and general knowledge-work systems.
The limiting competitive factor may increasingly be trustworthy execution over long task horizons; providers that cannot substantiate reliability could face slower adoption in higher-consequence workflows.

The trend: This is one data point in the push to turn generative AI from a drafting tool into an agentic layer for sustained, cross-functional professional work.

Discussion

@elonmusk Elon Musk on x
Based on strong positive feedback from customers in our beta test program, @SpaceXAI will make Grok 4.5 available to the public tomorrow. It is an Opus-class model, but faster, more token-efficient and lower cost.
@elonmusk Elon Musk on x
Our internal assessment is that Grok 4.5 is roughly comparable to Opus 4.7, but much faster. The combination of capability, faster speed and lower cost is what makes it competitive. We are closing the loop on real-world usefulness, not benchmarks. Hardcore engineers at Tesla &…
@artificialanlys @artificialanlys on x
SpaceXAI's Grok 4.5 scores 54 to place fourth on the Artificial Analysis Intelligence Index following only Fable 5, GPT-5.5, and Opus 4.8. It scores on par with GPT-5.5 in Codex on the Artificial Analysis Coding Agent Index in the Grok Build harness, at much lower cost Grok 4.5 […
@cursor_ai @cursor_ai on x
We've partnered with SpaceXAI to train Grok 4.5. It's our most powerful model yet and the first we've built for more than software engineering. [image]
@jshobrook Jonathan Shobrook on x
The 2T run is already in progress. Time to give Anthropic a run for their money.
@girikuncoro Giri Kuncoro on x
As an engineer who works on Grok uptime and reliability, here's how Grok 4.5 powers my workflow beyond coding: 1. Auto-triage alerts - correlate metrics + logs, match past patterns, root-cause with full codebase context 2. Compounding incident/debug learnings - reused when
@ssbrouhard Stephen Brouhard on x
@kunchenguid Interesting. I mainly use Codex 5.5 xhigh as supervisor due being on pro plan. I didnt notice the limitation bc I am usually single task focused. I can see at volume like your work, that would be an issue. A harness I have started using is Oh My Pi. Impressive so far…
@davis7 Ben Davis on x
SpaceXAi overtaking Google to become the third place lab is such a hilarious and sad unforced error from Google Cannot wait to find out in 5-10 years what actually went so horribly wrong My current ranking: 1) OpenAI & Anthropic (tie) 3) SpaceXAi 4) zAI 5) Google
@kunchenguid Kun Chen on x
grok 4.5 made me give grok build a serious run today here's my honest first impression (non affiliated neutral view point): 1. grok build is a very good harness firstmate stretches harness capabilities to their limits, and i've been testing it with claude code, codex,
@mntruell Michael Truell on x
Excited to release Grok 4.5 with @SpaceXAI. It's an Opus-class model that's fast and low cost. It's a significant step up over any model we've developed so far, including Composer 2.5, and has become the daily driver for many on our team. First of many releases. More soon.
@artificialanlys @artificialanlys on x
SpaceXAI just released Grok 4.5, and it ranks #4 on GDPval-AA v2 with an Elo of 1543 - behind only the latest Claude releases from Anthropic on real-world agentic knowledge work tasks Grok 4.5 achieved this score at a cost of $0.49 per GDPval task to sit clearly on the Pareto [im…
@gavinsbaker Gavin Baker on x
Grok 4.5. Pareto dominant for coding by the numbers. We will see on the all-important vibes. Instinct is the benchmarks are likely directionally accurate given the stated focus on real world utility. [image]
@elonmusk Elon Musk on x
Grok 4.5 context window will upgrade to 1M probably by next week
@nvidia @nvidia on x
Congrats to @SpaceXAI on Grok 4.5 — trained on NVIDIA GB300 NVL72 systems and purpose-built for coding, agentic tasks, and knowledge work. This is what happens when world-class AI infrastructure meets world-class AI research.
@openclaw @openclaw on x
Grok 4.5 from @SpaceXAI is live on OpenClaw. No OpenClaw update required, just connect your X Premium or SuperGrok subscription, select Grok 4.5 under the xAI provider, and use an Opus-class model that's fast, low cost, and ready for agentic work. [image]
@elonmusk Elon Musk on x
Rate of improvement is 🚀🚀
@elonmusk Elon Musk on x
Rate of improvement is accelerating. Users should notice a meaningful improvement in the usefulness of the Grok Build harness with our V9 foundation model (aka Grok 4.5) every week.
@spacexai @spacexai on x
Announcing Grok 4.5, our first model trained specifically for coding and agents. It was trained with Cursor and offers frontier intelligence at leading speeds and cost efficiency. https://x.ai/... [video]
@elonmusk Elon Musk on x
Grok 4.5 is not yet using our internally developed C/C++ inference software that exact maps to the GB300 hardware. Doubling or more of the current speed is probably achievable.
@scaling01 @scaling01 on x
wow Grok-4.5 is more token-efficient than GPT-5.5 [image]
@kimmonismus @kimmonismus on x
Grok 4.5 is a genuine surprise success. Not only is it now playing in the same league as Claude and OpenAI's GPT, it is also significantly cheaper. More token-efficient, less expensive to use, and still delivering outstanding performance: With this triad, it is a true [image]
@elonmusk Elon Musk on x
Grok will be able to call Imagine as a tool in agentic mode for image/video generation. As Imagine keeps improving, this will be amazing for game developers!
@elonmusk Elon Musk on x
Grok groks engineering. Next month's release will be another step-change improvement, as we close the loop on solving real-world engineering problems at Tesla, SpaceX, Neuralink and Boring Company.
@ryolu_ Ryo Lu on x
the start of a new era try Grok 4.5 in Cursor and let us know how it feels!
@elonmusk Elon Musk on x
We will continue to make refinements to the Grok Build harness and the 1.5T foundation model almost every day in response to user requests. The 2T model will finish training this month and be available to customers next month.
@synthwavedd Leo on x
The new “Big 3” is officially Anthropic, OpenAI, and SpaceXAI (sorry but every time I type that new name out it looks silly lol) You had a good run DeepMind, but what a comeback for xAI. Who knows what they could do if they took back the compute they've given to Anthropic and Go…
@stephenx_ Stephen Xie on x
handling office agent training for the big run was one of the most intense + fun things I've done at spacexai. we're a tiny team compared to oai and ant, but rapid iteration and careful recipe design go a long way. couldn't be more proud of the knowledge work team 🫡
@benjitaylor Benji Taylor on x
Sun is shining. Grok 4.5 is out. Good day. [video]
@daniel_mac8 Dan McAteer on x
Grok 4.5 is a “Wow!” moment. 🤯 > Opus 4.8 & GPT-5.5 level on benchmarks > Costs less than Sonnet 5 Is that real? Hard to believe. Added Grok 4.5 as an implementer agent in fable-advisor. It replaces Sonnet 5. Use Fable as the orchestrator and a combo of: 1. Grok 4.5 2. Opus [vide…
@teortaxestex @teortaxestex on x
Heroes literally saved Grok project
@benhylak Ben Hylak on x
um, guys? [image]
@teortaxestex @teortaxestex on x
Grok seems to get tired and start lazily cheating later into the session (247K/500K), or I just got unlucky in any case, the sheer speed and decisiveness of the model are amazing, this is what Gemini 3.5 Flash was supposed to be [image]
@beffjezos @beffjezos on x
SpaceXAI absolutely mogs in terms of intelligence per dollar. Asymptotically, this is how they win.
@kimmonismus @kimmonismus on x
Grok 4.5: $2 in / $6 out GPT 5.6: $5 in / $30 out Opus 4.8: $5 in / $25 out Grok 4.5 seriously is freaking good price-performance wise. Opus 4.8 level, Sonnet 5 pricing
@mweinbach Max Weinbach on x
Just ran Grok 4.5 High in a knowledge work bench It was just below GPT 5.5 High and Opus 4.8 High at roughly the same price as GPT 5.5 and slightly cheaper than Opus 4.8 High It's doing pretty well!
@beffjezos @beffjezos on x
Holy shit. SpaceXAI actually mogged Opus. Mad lads actually did it. 🥹
@iterintellectus Vittorio on x
this is actually insane [image]
@teortaxestex @teortaxestex on x
I believe that serving a model with higher margins off your compute as an AGI lab founder is cuckoldry. And frankly it's good enough that Elon could ask more, he's clearly redeeming the brand name here. xAI (sorry SpaceXAI) + Cursor = OP
@elonmusk Elon Musk on x
Try out Grok 4.5 in Cursor!
@billyuchenlin Bill Yuchen Lin on x
It is a great model, sir! And it's getting better and better. I'm very proud to work with the amazing team on this model @SpaceXAI! Would love to hear what you will build with Grok! Critical feedback is always appreciated! 🚀
@zephyr_z9 @zephyr_z9 on x
Testing Grok 4.5 Won't be surprised if Elon cancels the Anthropic & Google agreements and gets back the compute xAI is bacc
@theo @theo on x
Just realized I was testing Grok 4.5 extensively yesterday lol Pretty damn good and REALLY well priced
@wholemars @wholemars on x
I asked Grok 4.5 and Claude Fable to create a simple todo app. Grok build finished in 104 seconds, Claude Fable took 557 seconds. Screenshots of the results below, GitHub repo in comments. [image]
@zdhnarsil Dinghuai Zhang on x
Excited to deliver Grok 4.5, with which we pushed RL scaling to the next level and achieve top-tier agentic coding performance. The past few months have been intense for me — driving fundamental algorithmic changes on both RL stability and capability, iterating days and nights
@dannylimanseta Danny Limanseta on x
I got to try Grok 4.5 in early access in Cursor for the past few days and I absolutely enjoyed it. It feels like Opus 4.8 at 2x the speed at a much cheaper price point. I tasked it to brainstorm > plan > implement a big feature for my game (this act 1 boss fight) and it did [vide…
@amangotchu Aman Gottumukkala on x
~3 months since joining, SpaceXAI has acquired Cursor, locked billion-dollar compute deals, launched Grok Build, and shipped a world-class coding model. The trajectory here is unmatched and working on Grok Build + RL has been the most impactful work of my career. Try out Grok
@hesamation @hesamation on x
Elon wasn't messing around. Grok 4.5 is indeed Opus level, faster, and cheaper. Never thought I'd live to see this day but OpenAI and Anthropic have some serious competition now. [image]
@veggie_eric Eric Jiang on x
Grok 4.5 is my default for all my coding work, I freaking love this model. Frontier intelligence that won't break the bank. Grok 4.5: $2 in / $6 out GPT 5.6: $5 in / $30 out Opus 4.8: $5 in / $25 out
@benln Ben Lang on x
New Cursor & SpaceXAI model is now live Take it for a spin, double usage for the first week
@amanrsanger Aman Sanger on x
Very excited for this model. It's an enormous improvement over composer 2.5 and trained entirely from scratch. It's been a pleasure working with the SpaceXAI team on it. Even more excited by the slope of the effort and the models to come.
@alexabraham Alex on x
had fun making these (almost) one shots with grok 4.5 for the launch video imo this is currently the best model for designers who build things [video]
@ericzakariasson Eric Zakariasson on x
try grok 4.5 in cursor now! double usage for the first week included. its a good model [image]
@zhmeishi Zhenmei Shi on x
Have made Grok 4.5 + Grok Build as my agents for a while. They are excellent partners! Please try it and give us feedback 🚀
@sawyermerritt Sawyer Merritt on x
SpaceXAI has officially launched Grok 4.5 for the public. “Our first model trained specifically for coding and agents. It was trained with Cursor and offers frontier intelligence at leading speeds and cost efficiency.” [video]
@forwarddeploy Umesh Khanna on x
Been using grok 4.5 for everything from coding to drafting my emails/iMessages to even making a board game during our dinner parties 😂
@jasonbud Jason Ginsberg on x
please give Grok 4.5 a try. it's an incredibly useful daily driver.
@robinebers @robinebers on x
Cursor and Grok Build now have Grok 4.5 I've tested it since yesterday and it's a really solid model, big departure from Composer 2.5 weak on design, but *very* solid coder plus, faster + cheaper this is big! [image]
@benjitaylor Benji Taylor on x
Grok 4.5 is now available. Has been great to play with the model internally over the past few weeks. It's a real step change.
@imsh4yy Shayan on x
If the Grok 4.5 benchmarks hold, this is fantastic. Input: $2 / 1M Output: $6 / 1M [image]
@spacexai @spacexai on x
Grok 4.5 is efficient and fast. It uses half as many tokens per task, delivers higher tokens per second, and costs less than half as much as comparable models, at $2/M input and $6/M output tokens.
@spacexai @spacexai on x
Grok 4.5 is built for real-world engineering. It excels in large codebases and handles long-running tasks that span multiple repositories, hundreds of skills, and a variety of tools. [image]
@andrewcurran_ Andrew Curran on x
Grok strong! Was Elon actually underselling for once? [image]
@kimmonismus @kimmonismus on x
Seriously, what?! Did NOT expect grok 4.5 to perform THAT well. On par with GPT-5.5, cheaper than opus 4.8. Cursor deal paid off [image]
@ai_for_success AshutoshShrivastava on x
Grok 4.5 is rolling out. Holy smoke, SpaceXAI cooked well 🔥 Bring this to Cursor soon. I want to test it. [image]
@mweinbach Max Weinbach on x
Grok 4.5 is in Cursor already [image]
@teksedge David Hendrickson on x
Oh wow check out these specs for Grok 4.5. Pretty strong results! Maybe Elon was underplaying his new model. [image]
@bridgemindai @bridgemindai on x
New CursorBench results just dropped and Grok 4.5 is the story. #3 overall at 66.7%. Right behind Fable 5 Max at 70.5%. Now look at the cost column. Fable 5 Max: $17.32 per task Grok 4.5 High: $1.51 per task That is Fable level performance at roughly 1/10th the cost. And it b…
@scaling01 @scaling01 on x
Grok 4.5 Benchmarks [image]
@daniellockyer Daniel Lockyer on x
Grok 4.5 was just released in Cursor 👀 Price is $2/M input and $6/M output Fast mode is $4/M input and $18/M output [image]
@fixlationai @fixlationai on x
🚨 Grok 4.5 OUT NOW Grok 4.5 has been released, benchmarks show it performing similarly to Opus 4.8! First Grok model to use Cursor data 👀 [image]
@synthwavedd Leo on x
Grok 4.5 is out. First time I've been impressed by a Grok model! Congrats on the launch @SpaceXAI [image]
@tetsuoai Tetsuo on x
Grok 4.5 goes public tomorrow. Here's everything that's known. The model runs on V9, xAI's new 1.5 trillion parameter foundation, roughly three times the size of the v8-small architecture behind Grok 4.3. It's the largest model the company has shipped, trained on Blackwell GPUs […
@gauravisnotme Gaurav on x
One of the best use cases I have found this is generating CUDA kernels - either directly based on a problem statement or looking through Torch profiler traces and identifying opportunities for optimizations. The model is extremely good at going on in a loop where it collects a
@quantumfon Jon Farland on x
Never, ever give up. The customers I've worked with over the last few days have already seen significant improvements in a wide range of applications. This includes enterprise and consumer applications alike. I'm excited to see what you build!
@arnabgho Arnab Ghosh on x
7 years ago we built iSketchNFill (ICCV'19): interactive sketch→image GANs with Adobe Research. The code had quietly bit-rotted into oblivion. Grok 4.5 resurrected the entire thing. Faster than Opus, just as sharp. Old research code never has to die now.
@yagiznizipli @yagiznizipli on x
In my first try, Grok 4.5 found 10+ optimizations in oxlint, and almost doubled the performance of the linter.
@yunta_tsai Yun-Ta Tsai on x
Has been my regular work horse for weeks. Impressive indeed.
Emil Protalinski Emil Protalinski on linkedin
5 things you should know about SpaceX's Grok 4.5: — 1. SpaceXAI, which is the new name for xAI under SpaceX, has released Grok 4.5 (https://x.ai/news/grok-4-5). …
Scott Ryan Scott Ryan on linkedin
Grok 4.5 is out! The true Pareto frontier model that builders & leaders obsessed with both performance and real economics have been waiting for: …
Wang Dong Wang Dong on linkedin
Introducing Grok 4.5 — frontier intelligence priced to scale. We're just getting started. — https://x.ai/...
Rodrigo Mol Rodrigo Mol on linkedin
Most people tried xAI Grok once, got a mediocre answer, and never opened it again. That model is dead. — Grok 4.3 quietly became production grade back in April. …
Changran Hu Changran Hu on linkedin
Proud to see Grok 4.5 finally out! — We lazer-focused on true usefulness: models that reason better, code better, and solve harder real-world tasks end to end. …
@timkellogg.me Mr. Tim on bluesky
SpaceXAI announces Grok 4.5 — roughly Opus-level but half the token-price, also cheaper full cost — this was trained alongside Cursor — x.ai/news/grok-4-5 [image]
r/technology r on reddit
The AI that spawned MechaHitler and deepfake porn puts on a suit to become legal advisor and Excel jockey
r/cursor r on reddit
Introducing Grok 4.5 | SpaceXAI
r/grok r on reddit
Introducing Grok 4.5
r/singularity r on reddit
Introducing Grok 4.5

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