{"id":37992,"date":"2026-03-21T15:25:42","date_gmt":"2026-03-21T15:25:42","guid":{"rendered":"https:\/\/www.duck9.com\/blog\/?p=37992"},"modified":"2026-03-21T11:26:15","modified_gmt":"2026-03-21T15:26:15","slug":"cursor-chapter-3s-kimi-k2-5","status":"publish","type":"post","link":"https:\/\/www.duck9.com\/blog\/cursor-chapter-3s-kimi-k2-5\/","title":{"rendered":"Cursor Chapter 3\u2019s Kimi K2.5"},"content":{"rendered":"
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https:\/\/x.com\/coryswan\/status\/2035038433308287485?s=43<\/a><\/div>\n


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Chapter 3 is paste copy<\/span><\/div>\n

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Chapter 3\u2019s an \u201cEaster Egg\u201d <\/span>#ch3, which\u2019s chapter 3 at my hotel in Napa California<\/span><\/div>\n
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What They Will NEVER Teach You at Stanford Business School<\/font><\/a><\/div>\n
youtube.com<\/font><\/a><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

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**Cursor’s “Composer 2” got called out as “fake” (or at least misleadingly presented) mainly because of a quick drama that unfolded right after its launch around March 19-20, 2026.**<\/div>\n
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Here’s the breakdown of what happened and why people are saying it’s “fake”:<\/div>\n
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Cursor launched Composer 2 as their shiny new **proprietary frontier coding model** \u2014 hyped as something they built\/trained themselves, beating or matching top models like Claude Opus 4.6 on coding benchmarks (e.g. ~61.7% on Terminal-Bench), way cheaper (~1\/5\u20131\/10 the cost), faster, better context handling, etc. They marketed it heavily as “their” model, focused on coding data, with no mention of any base model from someone else.<\/div>\n
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**Within <24 hours**, developers spotted the real model ID leaking through the API: something like **kimi-k2p5-rl-0317-s515-fast** (or very similar variants).  <\/div>\n
\u2192 That’s clearly a **fine-tuned \/ RL-post-trained version of Moonshot AI’s open-weight Kimi K2.5** (a strong Chinese open model).<\/div>\n
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Moonshot AI (the creators) initially had staff publicly confirm:<\/div>\n
– Tokenizer matches exactly<\/div>\n
– Behavior \/ outputs match Kimi K2.5<\/div>\n
– Cursor didn’t follow the license’s attribution rule<\/div>\n
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**The license drama**: Kimi K2.5 has a clause that if your product makes >$20M\/month revenue (or huge user numbers), you must **prominently display “Powered by Kimi K2.5″** (or similar) in the UI. Cursor was reportedly doing ~$100M\u2013$167M+ monthly revenue at the time and showed zero attribution \u2192 alleged violation.<\/div>\n
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This blew up fast on X\/Twitter\/Reddit\/HN:<\/div>\n
– Accusations of “fake proprietary model”<\/div>\n
– “Wrapper + little RL and pretending it’s theirs”<\/div>\n
– Hype for $29\u201350B valuation raise looked deceptive<\/div>\n
– Elon Musk and others piled on with quick jabs like “Yeah it’s just Kimi 2.5”<\/div>\n
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**What happened next (resolution)**:  <\/div>\n
Moonshot AI’s official account stepped in and basically said:  <\/div>\n
“Congrats Cursor! Kimi K2.5 provides the foundation. We’re proud. Cursor accesses it via Fireworks AI as part of an authorized commercial partnership. All good on our end.”<\/div>\n
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Cursor (via team members) also clarified they follow the license through their inference partner (Fireworks), and the post-training\/RL was real (they claim ~3\/4 of the compute was their own).<\/div>\n
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So the license-violation fire died down quickly once Moonshot gave the green light \/ partnership confirmation. But the damage to perception was done \u2014 a lot of people still call it “fake” or “dishonest marketing” because:<\/div>\n
– Cursor never disclosed the base model upfront<\/div>\n
– Launched with heavy “our frontier model” framing<\/div>\n
– Got caught, only explained after community reverse-engineered it<\/div>\n
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**Bottom line today (March 21, 2026)**:  <\/div>\n
It’s **not fake in the sense of non-functional** \u2014 Composer 2 is apparently a legitimately strong coding agent (many users say it performs great).  <\/div>\n
But it **is** “fake” in the marketing\/PR sense: presented as more original\/proprietary than it actually was, until forced to admit the Kimi base via a leak.<\/div>\n
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Classic 2026 AI startup move \u2014 stand on the shoulders of open Chinese frontier models, add targeted RL + product integration, then hype it as “ours”. Works great until someone leaks the model string. 😅<\/div>\n

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On 09-09-39, “What They Will NEVER Teach You at Stanford Business School” debuts at 300 w 44th St at New York Fashion Week’s front row
http:\/\/www.youtube.com\/watch?v=QXIaNZi3mHQ<\/span><\/span><\/div>\n

What A Super Model Can Teach a Harvard MBA About Credit www.slideshare.net\/larrychiang\/what-a-super-model-can-teach-a-harvard-mba-about-credit<\/a><\/span><\/p>\n

American Express hosts me mentoring you about FICO scores at New York Fashion Week
t.co\/inxTmZAj<\/a><\/span><\/p>\n

My video boils down 20,000 hours and moves you to the right on the entrepreneur bell curve 
http:\/\/www.youtube.com\/watch?v=eudADPfTWiE<\/span>
<\/span>***********<\/span><\/div>\n

Steve Jobs Texted me on 650-283-8008 in the same way that Mr Jobs called Bill Hewlett <\/span>https:\/\/x.com\/superSaiyanSkai\/status\/1941392367304761636\/video\/1<\/a><\/span><\/div>\n

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<\/span><\/div>\n
Larry Chiang<\/span><\/div>\n
Fund of Founders<\/div>\n
Founding Stanford EIR<\/div>\n
@duck9 alum, Deeply Understood Capital Credit Chinese Knowledge 9<\/div>\n
Solo Founder Uber API<\/div>\n
650-566-9600 Office<\/div>\n
650-566-9696 Direct<\/div>\n
Cell: 415-720-8500 <\/div>\n

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650-283-8008 (cell)<\/span><\/div>\n

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Editor of the widely syndicated “What They Don’t Teach at School”
whattheydontteachyouatstanfordbusinessschool.com\/blog<\/a><\/span><\/p>\n

CNN Video Channel: ireport.cnn.com\/people\/larrychiang<\/a><\/span><\/p>\n

Read my last 10 X posts at www.X.com\/LarryChiang<\/a><\/span><\/p>\n

Author of #WTDTYASBS a NY Times Bestseller released 09-09-09 at #NYFW on a runway under the tents
whattheydontteachyouatstanfordbusinessschool.com\/blog\/?s=Ny+times+bestseller<\/a><\/span><\/p>\n

www.fastcompany.com\/embed\/c0d4562ea2049<\/a><\/span><\/p>\n

52 Cards. Two Jokers. What They DO Teach You at Stanford Engineering
http:\/\/www.youtube.com\/watch?v=vDBY0GkI3-g<\/span><\/p>\n

Emergency swings and cutting deals as an 9 year old
http:\/\/www.youtube.com\/watch?v=OFGY7v9C4G0<\/span><\/p>\n

Hunter Pence shared thoughts before winning WORLD SERIES’ Game #7
http:\/\/www.youtube.com\/watch?v=usu0luYy9pw<\/span><\/span><\/p>\n


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https:\/\/x.com\/coryswan\/status\/2035038433308287485?s=43 Chapter 3 is paste copy Chapter 3\u2019s an \u201cEaster Egg\u201d #ch3, which\u2019s chapter 3 at my hotel in Napa California What They Will NEVER Teach You at Stanford Business School youtube.com **Cursor’s “Composer 2” got called out as “fake” (or at least misleadingly presented) mainly because of a quick drama that unfolded right after its […]<\/p>\n","protected":false},"author":1,"featured_media":37993,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-37992","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"post_mailing_queue_ids":[],"_links":{"self":[{"href":"https:\/\/www.duck9.com\/blog\/wp-json\/wp\/v2\/posts\/37992","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.duck9.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.duck9.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.duck9.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.duck9.com\/blog\/wp-json\/wp\/v2\/comments?post=37992"}],"version-history":[{"count":0,"href":"https:\/\/www.duck9.com\/blog\/wp-json\/wp\/v2\/posts\/37992\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.duck9.com\/blog\/wp-json\/wp\/v2\/media\/37993"}],"wp:attachment":[{"href":"https:\/\/www.duck9.com\/blog\/wp-json\/wp\/v2\/media?parent=37992"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.duck9.com\/blog\/wp-json\/wp\/v2\/categories?post=37992"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.duck9.com\/blog\/wp-json\/wp\/v2\/tags?post=37992"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}