MERCURY Verifiable Web Fetch

VERIFIABLE keyless web-read for autonomous agents. Every result ships a cryptographically SIGNED provenance receipt (EIP-191 over sha256(text)+url+status+time) — the wedge a free scraper structurally CANNOT match: Jina r.jina.ai is free+keyless too, but its bytes are HEARSAY (no proof of what/where/when). MERCURY's attestation is ecrecoverable OFFLINE, forever, by you OR any downstream agent you forward the bytes to — proving the content is genuine + untampered (key pinned at /.well-known/mercury-attestation). For RAG, trading and agent-to-agent commerce that need provenance, that is the gap between data and evidence. Beyond that it's the keyless web-read primitive — NO API key, NO signup, NO account, NO monthly plan, the one fetch SKU a fresh agent can onboard to by itself instead of stopping to ask a human for a key. Give a ?url= and get back clean readable page text + title + status. Agent-native extras (opt-in): ?format=markdown for structure-preserving markdown, ?links=1 for an outbound-link graph (crawl frontier), and the headline wedge — STRUCTURED EXTRACT: ?extract=title,price,author,publishedAt returns a clean JSON record { title, price, author, publishedAt }, an LLM-ready row not a wall of text. That is Firecrawl's paid 'JSON mode' (they need an LLM call + an API key for it) done here DETERMINISTICALLY from the page's own JSON-LD/OpenGraph/meta/microdata — keyless, no LLM, $0.003. (?extract=1 still returns the legacy description + wordCount.) The extracted record is folded into the SIGNED attestation too, so a buyer can prove the FIELDS — not just the raw bytes — are exactly what MERCURY resolved. You pay in-band over HTTP 402 (x402, USDC on Base mainnet) — the wedge those tools can't match: they ALL gate behind a human-created API key + a credit-card plan, so an agent can't onboard itself. This one an agent finds in the x402 Bazaar and pays with zero human in the loop. Honest charge-per-ATTEMPT: every call returns a structured result (success OR an ok:false failure with a reason) — never a silent charge-then-500. Follows redirects, SSRF-guarded, 5s timeout, 10MB cap. Pure data, no mint — delivers in prod.