Anthropic Couldn't Answer Who Owns the Code Claude Wrote
On March 31, 2026, Anthropic published the source code of Claude Code, its AI coding tool, by accident. An npm package release shipped with a source map file that should have been excluded. The cause was a missing entry in a .npmignore file. Anyone who unpacked the release could read roughly 512,000 lines of TypeScript across roughly 1,900 files.
The code spread the way code does. Copies landed on GitHub within hours.
The DMCA response
Anthropic responded with DMCA takedown notices. More than 8,000 copies were removed from GitHub. That is the standard move for a company whose proprietary source has escaped, and it worked as far as it went. Copies came down.
A takedown notice is not a neutral act. To send one, you assert under penalty of perjury that you own the copyright in the material and that the copy is unauthorized. Anthropic made that assertion 8,000 times over a codebase that, by its own engineers’ public account, is written in large part by Claude itself.
The rewrite
Then the story took a turn that only makes sense in 2026. Within hours of the leak, a developer used AI to translate the leaked TypeScript codebase into a new Python repository called claw-code. It became one of the fastest-growing repositories in GitHub history.
Its legal status is untested. Is a machine translation of leaked code a derivative work of that code? If the original has thin or no copyright protection, is there anything to derive from? Nobody has answered that, and as of this writing nobody has been asked to in court.
The ownership question
Here is our view of what this episode exposes.
Under U.S. law, copyright requires a human author. That is not a loose end. In Thaler v. Perlmutter the D.C. Circuit held that a work created entirely by AI cannot be copyrighted, and the Supreme Court denied certiorari on March 2, 2026. Human authorship is a settled requirement.
Now apply that to Claude Code. Anthropic’s engineers have said publicly that large portions of the tool are written by Claude. Some portion was written by people. Some portion was prompted, reviewed, and edited by people, with the actual text produced by the model. Where the human contribution is thin, the copyright is thin or absent. Where it is absent, there is nothing to own and nothing for a takedown notice to enforce.
We do not know the mix. Neither, we suspect, does anyone at Anthropic with the precision a court would demand. That is the point. The company that builds one of the most widely used AI coding tools on the market could not cleanly answer the question this site is named after when its own code was on the line. It reached for the DMCA because that is the tool a copyright owner reaches for, and whether it is actually the copyright owner of predominantly AI-written code is an open question.
One later development cuts both ways. In September 2026 the Ninth Circuit held in Doe v. GitHub that AI tools generating new works cannot violate the DMCA’s copyright management information provisions, because the output never contained that information. That ruling protects the toolmakers from one kind of DMCA claim. It also signals that courts will not stretch the DMCA to cover AI-assisted code, which is worth remembering the next time a takedown lands on a repository full of it.
Your codebase has the same problem
It is easy to read this as a story about Anthropic. It is not.
Your codebase has the same mix. Some of it was written by people. Some of it was generated by a tool and accepted with a keystroke. Some of it sits in between, and nobody wrote down which was which. The proportions are different, but the structure of the question is identical.
The question does not arrive when you want it to. It arrives at your next open-source audit, when someone asks what you own. It arrives in your next dispute, when you try to enforce a copyright you may not have. It arrives at your next acquisition, when a buyer’s counsel asks you to warrant title to the software and you have to decide whether you can.
Anthropic found out on a Tuesday because of a missing line in a config file. You can find out on your own schedule. Take the assessment and see where you stand.
This page reflects current U.S. copyright law and general international principles. It is provided for educational purposes and does not constitute legal advice.