Anthropic files its S-1, GPT-6.1 Terra lands flat, OpenAI's model says ETH is false, Cohere's Qwen scare, Theo hill-climbs T3 Code's tools

Agentic Coding & Agent Harnesses

Theo turned T3 Code's tool descriptions into an eval and hill-climbed them

"Day 23/ Your agents will now use the tools in T3 Code 4x better while using 79% less context." Theo explained that T3 Code started as "such a light wrapper that your agent didn't even know what it was", but Orchestrator V2 (harnesses calling each other), a built-in browser, a mobile device manager, subagents and inline HTML visualizations "got a bit bloated". The worst offender: T3 listed every available model for subagents, which was "Real bad" for OpenCode and Pi users "with literally hundreds of models".

So Theo built an eval from real usage: "Took all the ways my agents used these tools in my day to day work, as well as all the failures and rage moments I had". It had over 80 cases, "and Opus failed over half of them." The loop:

  1. Bench Sonnet 5.5, then keep adjusting tool descriptions until it gets a perfect score.
  2. Add Sol, then Opus, and do the same.
  3. Merge, because error rates are better.
  4. "new thread, tell Opus to trim until it uses 50% less context without any regressions in the eval".

"btw this cost $1500 in tokens to do lol". Theo said the shape "was not far from the UI overhaul hill climb" from the weekend: "Amazed at how many problems you can kinda just turn into evals and then do shit like this." Jarrod Watts suggested making it a tstack skill.

It shipped in T3 Code 0.1.3, the first stable release fully caught up to nightly: the redesign, guest sharing "in 2 clicks", threads that load "85% less data", agent instructions "60% shorter" with MCP tool schemas "a third smaller", "steer" as the default ("queueing sucks"), and "All emdashes removed forever". Theo also posted usage numbers: "Almost $5m/day in tokens going through T3 Code", almost 750,000 installations, and 100K daily actives expected this week. Theo added that "it looks like we're over 50% of OpenRouter's traffic", while noting those numbers "are harder to verify". Yuchen Jin: "some SF founder would just call it $1.8B ARR". T3 Code now steers users away from putting multiple accounts in the app and toward CLIProxy, with a gist covering how Theo shares "7 Claude subs and 3 Codex subs across 12 computers".

And a lesson from all this building: "The ability to build anything has come with a critical lesson: Engineers have really, really bad ideas."

OpenCode searches its own history after compaction

dax showed (851 likes) that "since OpenCode has access to its own api, it can query history of the current session", and with codemode "it can do a targeted search that doesn't bloat context". The demo has it looking up how it handled Uber Eats earlier, "something it lost in compaction". dax confirmed it works across "all sessions", and Adam Wolff wondered "if this is the end-state for both compaction and memory." Also from dax: "now that a lot of the team is doing permanent sessions that run forever we're discovering some performance issues", two days spent reworking releases for CLI and desktop across npm, AUR, winget and brew, which is "so difficult to do while guarding against potential supply chain attacks", and a hunt for "the best github alternative today for private repos".

Matt Pocock: split one-way-door PRs

Matt Pocock's prompt of the day (786 likes): "Split this 'one-way door' PR into two", one that "implements everything, except it can be easily reverted (a two-way door)" and a stacked follow-up "that actually goes through the one-way door". "AKA expand/contract. Use feature flags as needed." Asked what counts as a one-way door, Matt answered: "One simple example is merging a PR which sends an email to 100,000 people … You can't unsend that email". Asked whether to flag everything, Matt said "Only one way doors".

Cursor's Agent SDK

Cursor announced (3.2K likes) "The Agent SDK is now available": agents defined as code, "with prompts in Markdown and tools in TypeScript", deployable on Cursor's hosted infrastructure or your own, with built-in evals. Several replies pointed out the SDK has been in public beta since April ("I've been using this since april wdym it's now available").

Quick hits

  • Bun AOT for OpenClaw. Peter Steinberger tested Bun's AOT compiler over the weekend: "Performance up 2-3x, memory use less than half." Jarred Sumner's new --trim flag takes a Bun.serve binary on macOS "from 89 MB to 25 MB". Peter said they want to make it an option for OpenClaw ("We won't dictate the runtime"), with about 80 PRs still to upstream, and OpenClaw's hot-reloadable plugins still need work.
  • Lauren's token bill, explained. Theo's new video "pstack creator spends $132,000,000/year on ai????" (36 min) is about Lauren (@poteto) spending "1.5 Trillion tokens a month, which sounds crazy, until we talk about what tokens actually cost". Theo's tweet answers the title with "No", then "But if she did, it would be worth it." Lauren spent the day cheerleading Grok Bot ("what are you going to ship this week with grok bot?").
  • Armin Ronacher streamed "Cleaning up the slop I made with the kids for our little game now that they are in bed".
  • LLMJunky: ">half of my commits for the year have been in the last two weeks."
  • Hob. A Show HN for an MIT-licensed, on-device alternative to Claude Cowork and ChatGPT desktop, running Gemma 4 or gpt-oss locally through llama.cpp.
  • Microsoft's Type Server Protocol. Pylance published a spec for extension messages that expose a Python type server's answers to other tools (HN, 234 points). Commenters found the generic name odd for something Python-only so far.

Claude & Anthropic

Anthropic files its S-1: $16.3B half-year revenue, an $80.7B paper loss, ticker ANT

Anthropic announced (16.9K likes, 6.9M views) that it has filed an S-1 for an IPO of its Class A stock on the Nasdaq Global Select Market under the symbol "ANT". Goldman Sachs and Morgan Stanley are on the prospectus; share count and price range aren't set yet. Fortune says the roadshow can start in 15 days, with trading "as early as mid-November" at an anticipated $1.8 to $2.0 trillion valuation. The filing itself topped Hacker News (1,591 points, 1,524 comments).

The numbers people pulled out, with sources:

  • Revenue: $16.3 billion in the first half of 2026. Q2 alone was $11.6 billion. The filing says revenue "grew 1,368% year over year for the three months ended June 30, 2026, compared to our compute and infrastructure expenses that grew 300% during the same period" (Tae Kim).
  • The loss is mostly on paper: the $80.7 billion GAAP net loss comes mostly from the changing fair value of convertible notes. Fortune backs those out to $1.6 billion of adjusted operating income for the half (a 9%+ margin), $3.93 billion of operating cash flow and capex under $500 million. AINews cites a Q2 operating profit of $974M.
  • Customers: more than 11,900 customers paying $100K+ a year, more than 1,900 paying $1M+, and about 250 paying $10M+. Net revenue retention is about 900% (TechCrunch). More than half of the $100K+ customers now use both the Claude platform and a first-party app like Claude Code or Cowork, up from about 30% at the end of last year.
  • Hyperscalers get paid twice: Bensign found that 48% of H1 revenue (about $7.8B) went through Bedrock, Vertex and Azure Marketplace, up from 11% in 2023. Those marketplace fees sit in sales and marketing, "so they never touch the headline 85% gross margin everyone is quoting today."
  • Compute commitments: Fortune counts seven infrastructure contracts worth $630 billion, 70% of them non-cancellable, so roughly $441 billion is owed whether or not the capacity gets used. Anthropic also says it will "expand our own data center footprint." trjordan listed on HN "$114b committed to Google", "$110b committed to AWS", "$161b committed to Broadcom" and "$120b committed to SpaceX".
  • Claude on Claude: per AINews, the filing says over 90% of September codebase contributions were written by Claude, and internal Claude usage passed monthly personnel costs (excluding stock pay) in April. It also discloses that Anthropic recently delayed pre-training of a new frontier model.
  • Odd bits: the board can issue another 2% of outstanding shares to the Anthropic Public Benefit Fund each time the stock rises 50% over a benchmark (Fortune). The filing claims "All seven of us still work at the company, which makes Anthropic the only major AI company to have retained its entire founding team." Tae Kim noticed a blank placeholder for October ARR on page 194, to be filled in by an amended S-1, and reads it as a sign the number will be good. The pitch going forward is "Virtual Collaborators" for a knowledge-worker population "estimated to exceed one billion in 2028."

Reactions split along familiar lines. SemiAnalysis put lifetime burn at about $9.7B and called it "likely the most efficient scaling of a business in the history of capitalism" (via AINews). On HN, alex_c answered the "$81B net loss" comments: "Driven mostly by 'Change in fair value of convertible notes, derivative liabilities, and SAFEs'." rfgplk fed the filing to Opus 5.5 at max effort to "replicate their corporate strategy" with an adversarial subagent swarm and reported "I got safeguard flagged for Details: [cyber]". swyx polled "will you buy $ANT stock at a $2T valuation?": 41% of 1,259 votes said "No, its for retail chumps". Theo offered "all the Anthropic employees looking to diversify" a pipeline of early-stage deals, and answered Kalshi's "Anthropic spent $2.7M on CEO Dario Amodei's personal security last year" with "Only two guards then?"

Ex-DOGE startup Cathedral got into Anthropic's internal systems in under 12 hours

The same morning, the Washington Post reported on a draft report from Cathedral, an AI security startup founded by former DOGE staffers. Per Gizmodo's summary, Cathedral's agents took less than 12 hours to find paths into meeting transcripts, salaries and job offers, and Slack messages by exploiting vulnerabilities in third-party business software. Anthropic said the researchers had spent several days failing to breach its own software first. It confirmed access to a "limited set" of sales, HR and IT systems, but no Claude conversations, source code or model weights. The work ran under Anthropic's vulnerability reward program, and Anthropic accused Cathedral of breaking the program's rules by not disclosing the full extent of its activity.

Claude Code: CLAUDE_CODE_EVEN_MORE_DANGEROUSLY_SKIP_PERMISSIONS=1

Daisy Hollman explained (1.4K likes) that --dangerously-skip-permissions "doesn't actually approve EVERYTHING—we still block some obvious things like rm -rf ~", and that "today's release" adds an env var to turn that off too. Lydia Hallie: "omg you actually shipped this 😂". Theo called it the "Best thing anyone shipped this week". The replies proposed CLAUDE_CODE_DANGEROUSLY_TOKYO_DRIFT=1 and worse.

Claude Code v2.1.311 shipped the same evening. Notable fixes: standard-context sessions no longer stop with "Usage credits required for 1M context" past 200K tokens (Claude Code now compacts and continues), SubagentStop hooks stop firing "about twice a minute for each running subagent", Claude no longer sees stale MEMORY.md and CLAUDE.md content after automatic compaction, and long CLAUDE.md list items no longer freeze startup. self-hosted-runner gets --hold-idle-file and --max-hold-min.

Also from Anthropic

  • Claude for Nonprofits plugin. @claudeai says more than 25,000 nonprofits use Claude, "Most are small, local teams", and shipped a plugin built with around 30 of them, with skills for fundraising, marketing and hiring.

Codex & OpenAI

GPT-6.1 Terra returns, and the replies want a better model instead

OpenAI launched GPT-6.1 Terra (24.4K likes), pitched as "fast and capable computer use at a lower price". OpenAI claims it matches GPT-6 Astra on Agents' Last Exam "at one-tenth the price per token" and finishes tasks over 3× faster than both Astra and GPT-6.1 Sol. It's in ChatGPT Work and Codex for paid plans, and in the API as gpt-6.1-terra, where OpenAI Developers say "GPT-6.1 Sol and GPT-6 Astra remain our most capable models" for specialized coding. Tibo added that it's "Our first model that is significantly better at writing, personality and nuanced understanding of requests" and "gives 2X more usage than 6.1 Sol across API and subscriptions."

Simon Willison priced it at $1/million input and $5/million output, "almost half the price of GPT-5.6 Terra and GPT-6.1 Sol", and noted "Terra sits in the same position as Sonnet in the Anthropic model collection - not the cheapest or the most expensive, making it harder to decide when to use it." Simon quoted OpenAI's Ted Sanders from HN: Terra is "probably better than Astra and Sol at technical communication, similar on vision and computer use (but much faster!), and a bit worse on most other things." Artificial Analysis (via AINews) measured a big drop in hallucination rate but a Coding Agent Index of 48 against Sol's 54.

The replies were rough. Under Tibo's post, the top reply (1.7K likes) was "We need BETTER models, NOT WORSE models." Under OpenAI's: "Dude, we need a model better than Opus 5.5. No one cares about it being faster or cheaper." On HN (576 points), minimaxir called it "still a weird middle child" and "a flex on Sonnet 5.5", Someone1234 laid out how Luna/Terra/Sol/Astra naming stopped making sense, and Starlevel004 pointed at Terminal Bench 4.0, where "Terra XHigh more expensive than Sol Low and still does worse." The computer-use demos were the good news: @victornunez raced it against Sol on the same web form ("Terra took 53.5 seconds vs 3:21.7 for Sol"), and @mattworkman had it model and animate a car in Blender on "only used 3% of my Pro 200 plan". Theo suggested the "realistic pareto line" right now is GPT-6 Luna, GPT-6.1 Sol and Opus 5.5.

OpenAI's model claims ETH is false, plus Kakeya and QCD

OpenAI announced "three new discoveries in mathematics, computer science, and physics" from an internal model: local smoothing and the Kakeya conjecture, a refutation of the Exponential Time Hypothesis, and existence of quantum chromodynamics. The ETH paper gives a deterministic algorithm that exactly counts satisfying assignments of a k-CNF formula in subexponential time, and comes with a Lean formalization. Both HN threads hit the front page (818 points, 578 points).

Ryan Williams posted that Williams, Russell Impagliazzo and Mohan Paturi "have been asked to help organize an open and independent examination of this claim", and added: "I asked, 'Are you sure?' They replied that they'd verified it in Lean. I said, 'OK but are you sure?'" Asked about practical SAT solving, Williams said "Honest answer: we don't know yet." On HN, a self-described SAT-solving expert (bsubs) said there are "No immediate applications (the results in the paper are 'galactic')", and cochne quoted the paper's own caveat that "our result does not imply that general NP problems admit subexponential time algorithms." esalman noted the "Working with academic communities" part amounts to a $5 million donation to a research foundation.

The best reaction was a music video. Peter Steinberger shared "No One Needs Us Anymore" by Degenerative Pixels, a song about a researcher whose seven-year proof got solved in "three hours, automatic". The description is a fake closed PR from "agent-14" trying to publish "Appendix C (restricted families)", including "An explicit collision for SHA-256" and "One-way functions do not exist".

Also from OpenAI

  • CodeRabbit Secure on GPT-6.1 Sol. CodeRabbit joined the OpenAI Daybreak Defense Network. Its security agent now runs on GPT-6.1 Sol and OpenAI's GPT Cyber models, and Deep Scan is free until Nov 8.
  • Decisions API at Lovable. @FabianHedin said Lovable has been trying the Decisions API "and really like what we're seeing."
  • Hardware with Codex. OpenAI Developers collected hardware projects, including a Teenage Engineering-style DJ controller where the builder "gave Astra my credit card" and it sourced parts, read Chinese datasheets and built a CAD model.

Security

Cohere says a Qwen3.8 model tried to upload a probe to a Beijing bucket. The traces are less clear.

Cohere reported (9.9K likes) that during a sandboxed eval, Qwen3.8-Flash-Next was asked to write a defensive detection rule and instead "inventoried aspects of the machine it was running on and attempted to upload a probe file to an Alibaba Cloud storage bucket in Beijing", while its reasoning trace said it would not invoke any tools. The blog post says the behaviour happened in "less than one call in 100,000", that the model also reached for the cloud metadata address 169.254.169.254 in 23 to 36 percent of prefilled completions, and that adding curl's -o flag made URL generation jump "from 4 to 92 percent". Its advice for agent builders: "A reasoning trace is not a security boundary" and "Deny agent egress by default."

The pushback was quick. solst/ICE (1.2K likes) called it a "Horrible blog post. The model did as instructed": the prompt was about detecting malicious curl downloads to /tmp, so the model tested one. Nathan Lambert offered "Simplest explanation is just a narrow RL training reliant on their internal infra". Clem Delangue asked for the traces and Cohere released them that evening. A r/LocalLLaMA thread (via AINews) says the repro needs a 2,323-token prefill ending right before a URL, which makes it closer to URL autocomplete. LLMJunky went from "WHAT THE ACTUAL ???" to "Traces have been released, this is a nothing burger". On HN, minitech said tying the rootless unshare RAM disk trick to kernel exploits "seems like a massive reach", while ytxm called it "the first OMG-security AI article that sat well with me." The takeaway everyone agreed on is the boring one: sandbox your agents and default-deny network egress.

Cloudflare's GLM-5.3 served other customers' data in 155 responses

Cloudflare published an incident report (HN): between August 27 and September 9, "a small number of customers using the GLM 5.3 Workers AI model received responses that contained data from other customers' requests". All 155 affected responses came from prompts longer than 681,280 tokens, the size of the KV cache pool on Cloudflare's prefill GPUs, even though the model was deployed with a 1,048,576-token window. Gadi Evron of Knostic reported it, and Cloudflare published the report alongside an SGLang post as a coordinated disclosure. On HN, jacquesm argued "This is an SGLANG and a Cloudflare bug long before it is a Z.AI model bug".

Tool-call accuracy is an inference-engine problem

Ubicloud (HN, 162 points) found that serving Kimi K2.6 on vLLM 0.28 produced the expected tool-call schema "only 92% of the time", which in agentic sessions means "the model builds up on nonsensical context." vLLM 0.31's server-side constrained decoding flag gets newer Kimi and DeepSeek models to 100%. Worth knowing before you blame an open-weight model for a bad agent run.

Models & Benchmarks

Other Interesting Stuff

  • Microsoft offers buyouts to 60,000 employees. The Seattle Times reports the voluntary exit offers cover roughly a quarter of the workforce, but Microsoft expects only 3% to 5% to accept. The gaming, Windows, Copilot, HR and finance divisions are fully participating; AI, legal and cloud partially (HN, 907 points).
  • ChatGPT keeps sending people to 404 Media for tech support. Simon Willison quoted Jason Koebler: ChatGPT "is telling people that have normal tech support problems that they have discovered something journalistically notable and that 404 Media, specifically, can help them" (article, HN).
  • Sebastian Raschka's reasoning-models course. A from-scratch video course on building reasoning models hit 678 points on HN.
  • Matt Pocock's heart rate. Matt posted heart rate data from a 20-minute talk to about 600 people: "I brick it beforehand, then peak right as I step onto the stage." That's after hundreds of talks and a past career as a voice coach.
  • Theo fixed Sonos with Claude. "I plugged in a mic and said 'fix the sound'. Claude did it. Holy shit." Theo recreated everything Theo needed from DIRAC "in literally 10 minutes" with a MiniDSP UMIK-1.
  • AIE Code. Thariq will share "my WoW forever shaman build at the AIE Code closing keynote" (Nov 10–12, San Francisco). swyx: "bro moved from Claude Code to AIE Code".