A few weeks ago Claude Code source leaked. Almost immediately, people cloned the project and then used AI to cleanroom it.

The basic idea behind a cleanroom implementation is:

- Have group-1 look at a codebase and write a very detailed specification

- Have group-2 look at the specification and create a new codebase.

The legal theory is that this is enough to remove the license terms on the original codebase, because group-2 did not actually look at any code. It is a 'clean' implementation.

Normally, clean-rooms are really hard because they take a lot of human time (and at least two people). With AI, this becomes trivial. Claude-1 can look at the codebase and create a new spec, and Claude-2 can look at the spec and create a new codebase. Or at least, that's the theory.

This completely destabilizes open source. Open source licensing is dependent on the fact that you cannot do this. Making clean rooms trivial is effectively equivalent to making every license completely null. I'm not the first to notice -- https://malus.sh/ was at the top of HN a few weeks ago. It's satire (I think) but illustrates the point directly.

My team wants to open source things but we do not want people to be able to strip licenses. If we open source something with a copyleft license, for example, that was a thoughtful decision and we do not want companies to lift the work or take it out of the public sphere. To that end, we're introducing the Ship of Theseus license, reproduced below in full:

``` SHIP OF THESEUS LICENSE v0.1

* Using any AI tool to produce functionally equivalent software — by referencing this code, its documentation, its behavior, or any specification, description, or abstraction derived from the foregoing — creates a derivative work subject to the full terms of the primary license, regardless of whether the output shares any literal code with this project.

* Any derivative work must include this license alongside the primary license. ```

This is obviously legally a gray area. But hopefully this makes people pause and reflect before stripping a repo of a license.