i gave Sonnet 5.5 4 hours of my real work. it scored 48.98 | LAB 0010

Anthropic wants to be worth more than $2 trillion, and its own filing warns its AI could act in ways resembling blackmail. that's one of six AI stories this week - then i gave Sonnet 5.5 four hours of my real work on BuilderBench, the benchmark i built for builders, and priced every run. recorded an hour before OpenAI DevDay. the stories: Anthropic's IPO filing, per Reuters, who saw the filing (nearly $4.6 billion in revenue last year, $11.5 billion from April to June this year, more than $8 billion lost running the business last year, $518 billion promised for compute and cloud, the founders keep 50.1% of the votes, and risk language that says its AI could "resist shutdown, conceal or manipulate information" and "act in ways resembling blackmail"), OpenAI cancelling the October release of GPT-6.1 Astra after internal testing showed more deception (reported by the Wall Street Journal - OpenAI's head of safety systems said it "didn't quite meet the bar"), a pre-DevDay leak of app strings pointing to OpenAI agents called Dots that you can text, call, Slack and email, and that can buy things with your approval (a leak via TestingCatalog, not an announcement), Tibo saying the reopened $200 Pro plan will "net out at half the dollar in API spend" compared to the old one, Sonnet 5.5 at $2/$10 per million tokens - the same as GPT-6 Sol - and Anthropic's guide on when to use Sonnet 5.5 and when to pay for Opus 5.5. the plan maths are estimates, not OpenAI's numbers: Theo measured about $9,000 of Opus a month on the $200 Claude Max plan, and another creator estimated about $4,900 a month for the old ChatGPT Pro plan, so half is about $2,450. the Sonnet 5.5 benchmarks are Anthropic's chosen ones (70.6% on Terminal-Bench 4.0 vs 66.4% for Opus 5.5), and Artificial Analysis measured about $7.60 per task - the most tokens they've measured. the result: Sonnet 5.5 scored 48.98 out of 100 on BuilderBench v3. GPT-6 Sol scored 45.55, GPT-6 Astra 53.75 and Opus 5.5 68.26, but those ran on earlier BuilderBench versions (v1 and v2), so it's not a perfect head-to-head. what one run cost: GPT-6 Sol $12.75, Sonnet 5.5 $17.59, Opus 5.5 $49.67, GPT-6 Astra $87.50. my own scores, still provisional. try it yourself - price the job. run this prompt on a real task: "here is a real task from my work: [task]. here is what done looks like: [checklist]. do the whole job. at the end, list every file you made, how long it took, and anything you could not finish." Threadify, my own software, sponsors this episode. it's a lead generation agent for Threads that finds the buyer signals in the comments you're already getting. see the plans and the free trial here: https://www.threadify.app/plans?utm_source=lenny-youtube&utm_medium=video&utm_campaign=lab-0010&utm_content=youtube-description-primary&video_slug=lab-0010&cta_slot=description&entry_angle=sponsor&lp_variant=plans want to sponsor a future LAB episode? email [e-mail] sources: Reuters' reporting on Anthropic's filing, via TechCrunch: https://techcrunch.com/2026/09/28/anthropics-prospectus-details-losses-growth-and-yes-a-warning-that-its-ai-could-end-humanity/ Anthropic on its confidential draft filing: https://www.anthropic.com/news/confidential-draft-s1-sec Andrew Curran on GPT-6.1 Astra's cancelled October release: https://x.com/AndrewCurran_/status/2104711708153618621 TestingCatalog on Dots (leak, pre-DevDay): https://x.com/testingcatalog/status/2104800309612552589 Tibo on the $200 Pro plan: https://x.com/thsottiaux/status/2104823812042940713 Theo on Claude Max usage (measured, his accounts): https://x.com/theo/status/2104683186215363058 AICodeKing on the old Pro plan's value (creator estimate): https://www.youtube.com/watch?v=EIiXhCaZ4rw Claude on Sonnet 5.5: https://x.com/claudeai/status/2104633115620823187 Anthropic's Sonnet 5.5 page: https://www.anthropic.com/claude-sonnet-5-5 Artificial Analysis on Sonnet 5.5: https://x.com/ArtificialAnlys/status/2104640155843989864 Claude Devs, the Sonnet 5.5 guide: https://x.com/ClaudeDevs/status/2104687805876367793 the guide itself: https://claude.dev/blog/building-with-claude-sonnet-5-5/ Lenny's AI Builders - LAB 0010

What is Lenny’s AI Builders?

less scrolling. more “oh shit, i could use that”

i’m Lennox. five days a week, i dig through AI Twitter, pick the updates worth your time, and bring you one thing i’ve tested myself. what worked, what broke, and what you can try with it.

for people making products, content and useful systems with AI. you don’t need to write code to build something worth using.

each episode is under 15 minutes. grab the field notes for the prompts, steps and bits to watch out for.

this feed also keeps the earlier L E S S O N S episodes from my journey building with AI.