folder	question	status
`cost-ab/`	Does pxpipe cost less on a real task?	~break-even. Compression is real but lands in `cache_read` (cheap at `$`, rumored-free at the subscription cap); session divergence dominates the totals.
`effective-context/`	Does pxpipe stay sharp in a context that overloads the plain column?	unvalidated — modern long-context Claude may not "drown," so run it before claiming a win.

What is validated: in the cost A/B's Rust-rewrite task, both columns ported a whole library to Rust and both passed all 5 tests with the exact expected integers — pxpipe through imaged spec + source. So compression didn't break a precision task. pxpipe's case rests on capability (not breaking real work, and effective context), not on saving tokens.

Shared tooling: ../eval/ab/analyze.mjs reads the two proxy logs (ab-on.jsonl / ab-off.jsonl) and reports the honest cost comparison.