Anthropic accidentally released part of the internal source code for its AI-powered coding assistant Claude Code due to “human error”, the company said on Tuesday.

An internal-use file mistakenly included in a software update pointed to an archive containing nearly 2,000 files and 500,000 lines of code, which were quickly copied to developer platform GitHub.

“Earlier today, a Claude Code release included some internal source code. No sensitive customer data or credentials were involved or exposed,” an Anthropic spokesperson said.

“This was a release packaging issue caused by human error, not a security breach.”

A post on X sharing a link to the leaked code had more than 29 million views early on Wednesday.

The exposed code related to the tool’s internal architecture but does not contain confidential data from Claude, the underlying AI model by Anthropic.

Claude Code’s source code was partially known, as the tool had been reverse-engineered by independent developers. An earlier version of the assistant had its source code exposed in February 2025.