Anthropic says engineering missteps were behind Claude Code’s monthlong decline after weeks of user backlash

Anthropic, the AI lab valued at $380 billion, has acknowledged that a series of engineering missteps were behind a widely experienced decline in the performance of its Claude Code tool that sparked a user revolt over the past month.

The latest admission, which came after weeks in which Anthropic had initially implied in its communications that nothing was wrong and that users were largely to blame for any performance problems and later said some of the changes had been made for users’ benefit, has done little to calm Anthropic’s customers—some of whom say they have already canceled their subscriptions.

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The feeling among some users that Anthropic had been gaslighting them potentially undercuts Anthropic’s attempts to market itself as more transparent and aligned with its users than rival OpenAI. Nor has the admission that there were performance problems done much to quell rampant speculation that the company is running short of computing resources and that Anthropic’s efforts to ration precious computing power were the real reason for the performance issues.

“Demand for Claude has grown at an unprecedented rate, and our infrastructure has been stretched to meet it, particularly at peak hours,” Anthropic said in a statement to Fortune. “We are doing everything we can to address this, and we are deeply grateful for our users’ patience.”

The statement went on to say that “compute is a constraint across the entire industry, and we are scaling our compute rapidly and responsibly—including through a recently announced expansion of our partnership with Amazon and Google, which will bring significant new capacity online in the coming months. Our priority is getting that capacity into our users’ hands as quickly as possible.”

The company also pushed back on any characterization that it had not been transparent with its users about the issues impacting Claude Code. “The Claude Code issues had specific technical causes that we documented in full in our postmortem, and the fixes are now shipped,” the statement said.

Anthropic has built much of its recent success on the loyalty of developers. Its Claude Code tool, launched in early 2025, has been popular with solo developers and enterprise engineering teams. The runaway success of the tool has helped send the company’s annualized recurring revenue run rate to $30 billion—more than triple its figure at the end of last year. However, the weeks-long performance decline and the lab’s slow response to user complaints, as well as several changes that users argue amount to stealth price hikes, are testing that loyalty.

The controversy could dent Anthropic’s bottom line amid an increasingly bitter race with rival OpenAI. The issues also come at a critical time, with both companies reportedly gearing up for initial public stock offerings later this year.

Following widespread complaints about Claude Code’s performance, executives representing the AI lab initially said the performance issues were the result of changes it had made to improve latency and in response to user feedback about token use. It said both changes were communicated via its public changelog—a running list of updates available to users. On Thursday, however, Anthropic went further, publishing a detailed engineering post acknowledging that three separate engineering missteps were behind the performance issue. In an effort to respond to some of the user complaints, the lab also said it would reset usage limits for all subscribers.

Anthropic’s newest admission is likely to increase already widespread speculation that the lab may be suffering from a compute strains after use of its products soared in the past few months.

Beyond the performance issues with Claude Code, the AI lab has also suffered a series of outages as usage has surged, introduced usage cap limits during peak hours, and is limiting the rollout of its newest, larger, and more expensive model, Mythos, to a select group of large firms. (Anthropic has said that the model’s cautious rollout is meant to guard against security risks posed by the model’s unprecedented cyber capabilities.)

The company’s rivals have also furthered rumors that the lab may be lacking the compute needed to maintain its recent customer surge. In an internal memo first reported by CNBC, OpenAI’s revenue chief claimed Anthropic had made a “strategic misstep” by failing to secure sufficient compute, and was “operating on a meaningfully smaller curve” than its competitors. Anthropic has notably announced fewer multibillion-dollar deals for data center capacity than some of its rivals such as OpenAI. While other AI companies are also facing compute constraints, Anthropic appears to be in the most difficult position, having grown far faster than it likely anticipated.

Anthropic declined to answer CNBC’s questions about the memo. Anthropic has also publicly stated it does not purposely degrade the performance of its Claude models.

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