GitHub enforces Anthropic DMCA notices on leaked code, but spin-offs and reworks remain online [Updated]

Update (April 2, 2026): Anthropic engineer Boris Cherny has acknowledged that the DMCA notices sent to legitimate forks of Anthropic’s own public Claude Code repository were unintentional. “This was not intentional, we’ve been working with GitHub to fix it. Should be better now,” he wrote.

Developer Theo (t3.gg) was among those affected. His fork had no leaked source code, only a pull request where he had edited a skill. Tech newsletter writer Gergely Orosz called the incident DMCA abuse, noting it is “neither OK, nor legal to file a DMCA takedown for something that breaks no copyright.”

Original article published on April 1, 2026, follows:

GitHub has started removing thousands of copies of Anthropic’s leaked Claude Code source code after the company filed DMCA takedown notices.

The action hit hard and fast. More than 8,100 repositories were disabled, including the original leaked repo called nirholas/claude-code and its entire fork network.

That means that a lot of developers saw their mirrors vanish in no time. One simply posted, “anthropic lawyers just woke up and taking down my repository.” Others reported the same thing on X.

The leak itself started on March 31 when Anthropic pushed version 2.1.88 of its Claude Code npm package. That package accidentally included a roughly 60-megabyte source map file. I covered the whole ordeal here. Anyone could use it to reconstruct the full TypeScript source for the closed-source AI coding tool. Within hours, the code had spread on GitHub.

GitHub enforced the notices on a large scale. Because the fork network was bigger than 100 repositories and Anthropic claimed that most forks infringed to the same extent as the parent, they disabled the whole network of over 8,100 repositories. In the official DMCA filing, Anthropic’s IP counsel stated that the entire repository was infringing. The company also removed the problematic npm package, going straight from version 2.1.87 to 2.1.89.

The sweep also appears to have gone further than intended. Developers started reporting DMCA notices for forks of Anthropic’s own public Claude Code repository — not copies of the leaked source. Developer Danila Poyarkov shared on X that he received a takedown for simply forking the public repo. Another user, Daniel San, got a similar GitHub email referencing a fork of the public repo that contained only skills, examples, and docs — nothing from the leak. As one reply put it, getting a DMCA for forking a public repo is “like getting a parking ticket for using a public sidewalk.”

Here’s the twist though. Not everything is disappearing.

While the straight copies are vanishing, a different kind of project is thriving. Developers didn’t just fork the leaked code. They rewrote major parts of it from scratch. One popular effort, called OpenCode, now offers similar AI coding assistant features but works with any large language model you want — GPT, DeepSeek, Gemini, Llama, MiniMax, whatever.

Because these are original implementations rather than literal copies, they look safe from the DMCA notices, at least on paper. The OpenCode project picked up serious traction almost overnight, with one early version even drawing a quick “Banger 😂” reaction from Elon Musk on X.

So yes, the community turned a proprietary leak into working open-source alternatives in a single day.

Anthropic called the original incident a simple human error in packaging. No customer data was exposed. Still, the company has moved aggressively to limit how far the source spreads, just as it did in a smaller leak last year.

Anthropic engineer Boris Cherny said, “Our deploy process has a few manual steps, and we didn’t do one of the steps correctly.” The team has already shipped a couple of fixes and is adding more sanity checks and automation. He also added that mistakes like this point to process or infra, not any one person.

For the moment, the rewritten versions stay online and appear to be gaining users fast. The directly leaked files are harder to find, but the ideas they contained are already loose on the internet.

Update (April 1, 2026): Added information about DMCA notices hitting forks of Anthropic’s own public Claude Code repository.

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