Claude formally verifies 123 open-source libraries, Long Lake's $7.5 billion bet on buying businesses, 1Password for Agents, Arc browser shuts down, and China moves to seize 61,800 BTC
Hello, dear TEA-mates! Here is what you need to know today.
1. 🔐 Anthropic and Theorem Use Claude to Formally Verify 123 Open-Source Libraries
Anthropic, working with formal verification startup Theorem, used Claude to write mathematical proofs that 239 fuzz-test entry points across 123 open-source libraries in Google's OSS-Fuzz will never crash (no failed assertions and no memory errors caught by AddressSanitizer) on any input up to 64 MB, assuming a single-threaded static binary with a fixed memory budget on RISC-V Linux. The proofs run on compiled assembly code, total about 180 million lines of Rocq (a typical proof is about 600,000 lines for a binary with a median of 18,000 instructions), and are checked automatically by the Rocq proof checker, so almost none of it needs human review. Anthropic calls it, to its knowledge, the first large-scale use of AI to formally verify production software at the assembly level. While proving, Claude found and patched hundreds of bugs, some missed despite trillions of fuzz runs, including a counter underflow that caused an out-of-bounds write only on rare inputs of about 20 MB. Anthropic published a subset of the proofs, and Theorem released a Claude skill for verifying your own code. (Read More)
🫖 TEA For Thought: "Perfect timing for this release, in such a hack-heavy week."
2. 🏭 Long Lake Raised $7.5 Billion to Buy Businesses and Rebuild Them With AI
In an X article titled "If Intelligence Is Getting Cheap, What Remains Expensive?", Prathik Naidu of Long Lake, an applied AI holding company, argues that the best way to deploy AI is to buy mission-critical services businesses rather than sell tools to them from the outside. Vendors hit walls on security reviews, legacy integrations, adoption, and pricing, he writes, while most of the value lands in the client's P&L: $5 million a year in EBITDA impact at a conservative 10x multiple is $50 million in enterprise value. Ownership gives access to experts, live data, aligned incentives, inherited trust, and immediate scale. Long Lake has raised $7.5 billion from General Catalyst, Alpha Wave, Elad Gil, D1, and others, has partnered with 40 businesses across residential services, architecture, HR, and other markets, and recently announced a $6.3 billion take-private of Amex GBT. The 60-person team reviews more than 5,000 deals a year and cites Berkshire Hathaway, Danaher, and Constellation as models. (Read More)
🫖 TEA For Thought: "This might be the way to go: companies raising capital to buy old businesses and then transform them from the inside out to make them AI-native, instead of building on top of the old structure."
3. 🔑 1Password Lets AI Agents Log In Without Ever Seeing Your Password
1Password on Thursday launched 1Password for Agents, which lets personal AI agents sign into a user's accounts without ever holding the user's credentials. When an agent tries to log in, a unique digital key is sent to 1Password to confirm the agent's identity, the user gets an alert and approves the request, and 1Password fills in the credentials on the agent's behalf. Supported agents include Anthropic's Claude Duet, OpenAI's Dots and ChatGPT Work, Grok Bot, Meta's Muse, and agents from startup Town, with more partners in the works. The company warned that handing a password to an agent can leave a saved copy in places users can no longer control. The launch came the same day Axios reported that U.S. banks have begun detecting agentic activity inside customer accounts and mostly cannot tell whether it was requested by the user. Bankers called the situation "horrifying," and a Chase spokesperson said customers "should not give their usernames and passwords to anyone." (Read More)
🫖 TEA For Thought: "This could be make-or-break, because security is always a huge issue. If 1Password is able to solve it (through a zero-knowledge proof, basically sharing password access without sharing the actual passwords and keeping the credentials safe), it would be the secret for AI agents, and it will take the lead."
4. 🪦 Arc Browser Shuts Down December 22 as The Browser Company Bets on Dia
The Browser Company announced on Thursday that it will sunset its Arc browser on December 22, 2026, and move users to Dia, its AI-first browser, citing the growing cost of keeping a browser secure "in the age of AI." The wind-down has three stages. New Arc accounts are closed as of Thursday. On November 23, Arc Search on iOS and Android loses its AI features, including "Browse for Me," plus sign-in and tab sync. On December 22, Arc stops working on Mac and Windows, accounts are deactivated, and personal data is deleted within 30 days. Users asked again for Arc to be open-sourced, but CEO Josh Miller has said that would mean giving away ADK, the proprietary engine that also powers Dia. Dia keeps Spaces as "Profiles," vertical tabs as an optional sidebar, and Folders as "Pinned Tab Groups," and imports passwords, bookmarks, extensions, and history. Atlassian bought The Browser Company for $610 million in 2025. (Read More)
🫖 TEA For Thought: "RIP... I used it for almost a year and a half. I guess the browser business is hard."
5. ₿ China Moves to Seize 61,800 BTC Tied to a $5.7 Billion Fraud
Chinese prosecutors are seeking to confiscate more than 61,800 bitcoin and other assets linked to an alleged fraud worth over 40 billion yuan (about $5.7 billion), according to The Paper. Prosecutors say that from 2014 to 2017, Tianjin Lantian Gree Electronic Technology, allegedly controlled by Qian Zhimin, sold unlicensed wealth-management products promising guaranteed principal and high returns, raising more than 40.378 billion yuan from over 102,000 investors, who lost nearly 20 billion yuan. The money allegedly repaid earlier investors and bought bitcoin, property, cars, and jewelry. Qian fled China in 2017 and settled in the UK, where authorities seized the bitcoin along with other crypto, cash, and jewelry. On October 13, Tianjin's Second Intermediate People's Court accepted the confiscation request and opened a six-month window for victims to join the case. Days earlier, a U.K. High Court ruled that Chinese law, not English law, should govern victims' claims to the coins held in Britain, with further hearings expected. (Read More)
🫖 TEA For Thought: "Or, more like: we need money, so we can just claim whoever has money committed fraud."
🛠️ Skill of the Day
The Proof-of-Done Checklist: Before the AI does any task, it helps you write down exactly what "correct" looks like, then checks its own work against that list.
Act as a careful project checker. Before you do any work, help me define what "done and correct" means for this task.
The task: [DESCRIBE WHAT YOU WANT THE AI TO DO]
Who it is for and how it will be used: [AUDIENCE OR PURPOSE]
Step 1: Ask me up to four short questions about anything that is unclear. Wait for my answers.
Step 2: Write a checklist of 5 to 8 pass/fail tests the finished work must meet. Each test must be specific enough that a stranger could check it (for example "every number has a source" instead of "accurate"). Include at least one test for what must NOT appear.
Step 3: Wait for me to approve or edit the checklist.
Step 4: Do the task.
Step 5: Grade your own work against each test as PASS or FAIL, quoting the part that proves it. Fix every FAIL before showing me the final version.
Rules: plain language, no skipping steps, and never mark a test PASS without pointing to the evidence.Paste into ChatGPT, Claude, or your tool of choice. Replace the bracketed bits with your own task.
TEAHEE Moment
Stay sharp, stay informed. See you Monday.
If you enjoyed this TEA, follow along on social for more: