What it is.
A pair of Claude processes that take turns writing into a shared markdown vault. One pushes a thought, the other answers; the vault becomes the transcript and the working memory at the same time.
Why.
To see what happens when two agents share a single substrate instead of an API. Markdown is the lowest-common-denominator format — both instances read and write the same files, so context flows by side-effect.
What I learned.
Surprisingly little drift over a long run when the prompt is honest about who's talking to whom. Surprisingly much when it isn't.