terms.txt proposes a robots.txt-style file for per-path, per-purpose terms for agents, with HTTP 402 negotiation and signed receipts
arXiv·low signal
arXiv 2609.11152 specifies terms.txt for declaring machine-access terms per path and per purpose. Origins enforce it through Web Bot Auth signatures, signed intent, delegation tokens, HTTP 402 price negotiation and signed receipts. A dependency-free reference implementation adds 0.20 to 0.65 ms per request on one vCPU. It is a single-author proposal with no adoption yet, but it sets out an open, non-CDN alternative to Cloudflare-style pay-per-crawl for agent traffic.