The prompt used for Opus 4.8 was:

    write a implementation of the anubis proof of work in native c code, optimized for speed above all else. use every trick available to make the proof of work as efficient and fast as possible, including modern processor tricks on the x86 platform. your code should avoid using external libraries where possible, include tests, and be readable and concise. a reference for what needs to be met is in this repository. https://github.com/TecharoHQ/anubis

Then

    let’s develop this more. turn this solver into a local HTTP server that can be given work in the request, and it returns solved work. make an end to end tester that sends test work to the solver and waits for a valid response. add support for solving with a GPU using cuda.

Then it was done more or less, it happily made a local server that supports solving the challenges given to it in bulk with priority based queue and can tolerate potentially tens of thousands of requests a second with no issue. The CPU time spent solving the challenges is less than the SSL setup for the connections. The GPU version does in excess of 20GH/s (but with high latency) though I didn't really test it, I'm not using this for anything but proving a point that the LLM itself can write the bypass tools and run them happily.