Anthropic is rapidly growing head count, concerned about retaining top talent, and trying to build a "low-ego" culture. Those are among the workplace insights in the Claude maker's IPO filing released Monday. The more than 200,000-word document reveals what it takes to thrive as an employee — or an "Ant," as staffers are called — and why the company is so focused on retaining its top talent. Here's a look at three workplace themes in Anthropic's S-1: Anthropic said its workforce grew from about 940 employees at the end of 2024 to about 5,300 as of late September.

The more than fivefold spike in head count in less than two years is notable on its own. Yet, without Claude, it could have grown more. Anthropic said the tool is helping its staffers take on work that would traditionally have required much larger teams — something many tech companies are looking to do to become more nimble. Most Anthropic employees work in research, engineering, and product development. The company said its strategy is to use Claude to grow the business "without growing head count linearly, resulting in extraordinary contributions per employee."

One place where that's evident is in software engineering. The company said these workers increasingly direct and review Claude's output rather than write code line by line. Claude wrote more than 90% of the contributions to the company's codebase in September, while average daily code contributions per engineer in the third quarter were more than 45 times their average daily level in 2024, Anthropic said.about Anthropic's S-1 filing: Recruiter Martha Heller said it's little surprise to see Anthropic talking up its use of Claude.

"Of course they're going to eat their own dog food," she said. In any case, Heller said, the company still needs people to provide oversight of AI's activities. Yet the gap between staffing levels and output could grow, said Aaron Cleavinger, an executive recruiting partner at Flatiron Search Partners.

"Head count is becoming a less meaningful measure of organizational capability," he said. Cleavinger said it's not yet clear what the new measure will be, though Anthropic's approach suggests companies might put greater emphasis on workers' productivity and business impact. Despite having significantly upped its employee count, Anthropic said it's highly dependent on its senior leaders and key technical team members. The company warned that their departure could disrupt operations and slow innovation.

While that's true for any employer, Anthropic faces additional challenges. It's a fast-growing startup in a booming industry, where few people have the right technical skills — and those who do are being heavily courted by competitors. Winning the war for talent is half the battle. Anthropic is also part of an industry where some workers have quit and issued dire public warnings about the dangers of increasingly powerful AI.

For example, safety researcher Jacob Coxon resigned from Anthropic last month, saying the company and his former employer, OpenAI, were moving too quickly toward increasingly powerful AI without a sufficient plan to control it. "That's not garden-variety turnover," said Liane Davey, an advisor on team effectiveness to executives at companies such as Amazon and Google. If employees determine that their work poses an existential threat, no bonus can simply erase moral qualms, Davey added.

In its S-1, Anthropic said many key technical workers are motivated by its mission and by the chance to tackle specific AI problems. However, if their beliefs change, or another organization seems more aligned with their personal beliefs or professional goals, "we may face increased difficulty retaining such personnel," Anthropic said. The company's internal data suggests that, at least for now, turnover isn't a significant problem. It said it experienced only about 1% "regrettable attrition" in a 12-month period ending on September 30.

Further, Anthropic may have a thinner pipeline of junior technical talent to elevate. Anthropic said in a recently released internal report that it has been hiring for a "smaller share of junior technical positions" as AI agents have been deployed across the firm to write code, fix bugs, and handle other tasks. Anthropic touts a "low-ego" or "ego-light" culture, meaning all employees are expected to prioritize what's best for the company over personal status, credit, or seniority.

It uses similar language on its website in a section describing its values. In the S-1, the company went further, saying the arrangement allows for an "unusually short" distance between a research insight and a released product. Anthropic also said a shared purpose, paired with low ego, translates directly into less organizational friction and greater impact per employee. "Our teams operate in a truth-seeking environment where the best argument wins, not the loudest voice or the most senior title," Anthropic said.

Jamie Shapiro, an organizational psychologist and CEO coach, said that logic makes sense because good ideas can come from anyone within an organization, especially those who directly interact with customers. "An organization that has idea meritocracy is going to get the best ideas," she said. However, as Anthropic grows, the more challenging task will be ensuring its hiring, recognition, promotion, and accountability systems reinforce its ideals — rather than allowing exceptions that undermine them.

"The bigger the organization, the harder it is to make sure everyone is living and breathing the culture it wants," said Shapiro. "Culture is defined by the worst behaviors you allow."