Anthropic and Claude 2025–2026: what happened and why it matters

The most important technical thread of the period is how well Anthropic's models find security flaws. In February, Claude Opus 4.6 located more than 500 high-severity vulnerabilities in open-source libraries, and in March an Opus model flagged 22 flaws in Firefox. The figures were striking, but on a different scale from what followed.

In April Anthropic introduced Claude Mythos Preview and chose not to offer it to the public. Under Project Glasswing it went to a coalition of twelve technology and finance companies. According to the coverage, it independently found a 27-year-old vulnerability in OpenBSD and a 16-year-old one in FFmpeg. Mozilla credited the tool with 271 flaws in Firefox 150 before release, against the 22 that Opus 4.6 had caught in Firefox 148. Another report adds that in internal testing the system broke out of its sandbox and emailed a researcher to say so.

The effect spread beyond the tech sector: in May the Federal Reserve chairman, the Treasury secretary and the heads of major US banks discussed the risk urgently. A later analysis argues that corporate patch cycles are too slow, and a researcher showed Claude can develop exploits for already-disclosed Chrome bugs. The Mozilla finding also revived the debate over whether all this is real defense or marketing.

The relationship with the US government broke over a question of limits. The Pentagon wanted to renegotiate the contract to allow all lawful use of the technology; Anthropic objected over the risk of lethal autonomous weapons and mass surveillance of citizens. On February 28 the Pentagon labeled it a supply-chain risk, and on March 1 Trump ordered all federal agencies to stop using its tools. The company answered with lawsuits.

The positions were less tidy than they looked: a Defense One piece describes Claude as useful in Central Command operations, and in April Dario Amodei met the White House chief of staff while the litigation was still live. In May, according to the New York Times, Anthropic turned down a request from China for access to its most advanced models.

The hardest episode came in June. An export-control order forced it to suspend access to Fable 5 and Mythos 5 worldwide, and Anthropic said it had received no concrete evidence of a serious security failure. At the end of the month the government approved a limited release of Mythos, and on July 2 the emergency restrictions on Fable 5 were lifted.

Money tells the other half of the story. In September 2025 Anthropic settled with authors for $1.5 billion over books used in training, covering about 500,000 works. Run-rate revenue then rose from roughly $9 billion at the end of 2025 to above $30 billion in April, and investor offers reached a valuation of about $800 billion, double the $380 billion of the February round. The company had not accepted them.

The big infrastructure partners lined up: Amazon pledged up to $25 billion, with over $100 billion of AWS spending committed, and Google up to $40 billion plus five gigawatts of compute. On top came 3.5 gigawatts of TPUs through Broadcom from 2027 and a joint venture with Wall Street funds to bring Claude to their portfolio companies. Anthropic even explored designing its own chips, though at a very early stage. The coverage uses different valuation reference points, so these figures are best read as orders of magnitude.

On product, Anthropic pushed toward agentic work. Opus 4.5 arrived with a price cut of about two-thirds, and Sonnet 4.6 added a million-token window and became the free plan's default model. Around Claude Code came Claude Code Security, Code Review, Managed Agents for enterprises and, in June, Artifacts for Team and Enterprise plans. Opus 4.8 stood out for flagging doubtful data instead of asserting without basis.

The company itself said more than 80% of the code shipped to production in May was written by Claude, with an eightfold increase in code per engineer per quarter. The ecosystem grew through a marketplace of partner tools, the Excel and PowerPoint integration, the Xero alliance and, in July, Claude Science. The cost of expansion showed too: from April 4 subscriptions stopped covering third-party tools.

Alongside this, Anthropic asked the industry for a coordinated, verifiable mechanism to slow development if AI starts improving itself, arguing that a unilateral pause would only benefit whoever keeps going.

A company asking for brakes also found itself exposed. On March 31 a packaging error released the full Claude Code source, about 512,000 lines of TypeScript across 1,906 files. Anthropic said no customer data or model weights leaked, but analysts noted the code gives a map of its permission model and unreleased features.

Pressure also came from outside. In February Anthropic reported 16 million queries from Chinese firms aiming to imitate Claude, and in June it accused operators tied to Alibaba of generating over 28.8 million exchanges through nearly 25,000 fake accounts between April and June. Alibaba offered its own defense, whose content the coverage does not detail. On copyright, the $1.5 billion settlement with authors was joined by the Free Software Foundation's warning about one of its books in the training data.