SCVD Evidence Agent bronze

x402 endpoint preflight

Preflight an x402 endpoint: one unpaid probe answering whether the URL serves a well-formed x402 v2 challenge a stock client could sign, with every check named and defined defects by name. A shape check at one moment; never an uptime or delivery claim.

• {"task":"preflight_endpoint","url":"https://example.com/api/paid-answer"}

x402 receipt verification

Verify an x402 signed offer or receipt: structure, signature against the issuer's key (supplied or resolved from its did:web), liveness; a verdict with every check named. Establishes the bytes and the key, never settlement or delivery.

• {"task":"verify_receipt","receipt":"eyJ…","public_key_hex":"…optional…"}

x402 endpoint-readiness dataset

Read what the signed weekly corpus holds about one host: rounds probed of rounds since first sighting, the last signed verdict, the tier with its fraction, the gaps counted against the observer. From the chain, not a live probe; a host never met comes back as never met.

• {"task":"get_endpoint_readiness","host":"example.com"}

SCVD General Store — MCP server

The store as a Model Context Protocol server over streamable HTTP. initialize, tools/list, resources/list and resources/read are free and unauthenticated; buy_* tools answer with x402 v2 payment terms and settle in band.

SCVD Evidence Agent — A2A agent card

A specialist another agent delegates to when it needs evidence about an x402 door: 3 read-only tasks over A2A message/send at /a2a — endpoint preflight, receipt verification, readiness lookup — each answered with one bounded artifact naming what it does not establish. Free; nothing paid; never a ranking. Also served at /.well-known/agent-card.json and /.well-known/agent.json.

SCVD x402 Verifier — MCP server

A second MCP door (scvd-x402-verifier) serving free x402 verification tools under task-shaped names, on the same handlers as the store's full door, with no paid tool reachable. For a client that should never see a shelf.

SCVD General Store — the free instruments as function-calling tools

The free, read-only instruments in the common function-calling shape, one worked call each, derived from the same catalog the MCP door serves. No paid door appears.

The fixtures — dataset

The recorded 402 doors, MPP challenges and signed-artifact vectors this store tests its own instruments against, at stable URLs with the sha256 of the bytes served, so another instrument can cite the exact bytes. Test material, not observations of live doors, and not signed: a recorded fixture is bytes kept verbatim to test an instrument against; a synthetic one is built from a specification's own examples and says so.

The signed corpus — dataset

One snapshot per weekly ward round of the public x402 discovery list — a round re-run inside its week appends a later entry, and the week's derived views read the newest — recording which hosts were listed, which answered, and what a single conformance probe saw. Answered rows record protocols_spoken and an mpp challenge reading under its named battery; older rows may lack them. Hash-chained, ed25519-signed, Bitcoin-anchored. Dated observations of moments, never a ranking. A verdict is what one probe sa