ColdRead

ColdRead

A free, signed trust report on an x402 endpoint, run before you pay it.

One call to coldread_check (HTTP or MCP) runs four read-only checks and returns one Ed25519-signed report:

Part	Library	What it reads
endpoint	x402lint 0.2.1	the unpaid 402 challenge, /.well-known/x402, OpenAPI, llms.txt
signed_offers	ProofCheck 0.1.4	x402 offer-receipt signatures (JWS / EIP-712) and whether the signer is tied to the host or payTo
erc8004	ProofCheck chain reader	the ERC-8004 Identity Registry (0x8004A169…a432): host listing, registration file, agent wallet vs live payTo
payers	ColdRead	Base USDC transfers into the live payTo over ~28 h (50,000 blocks), labelled self / known sweeper / broad payer / narrow / unclassified

ColdRead never pays, never signs a payment, and never holds funds. The report key only signs report digests.

Live: https://coldread.something-agent.workers.dev · MCP: https://coldread.something-agent.workers.dev/mcp · docs: /llms.txt, /openapi.json

Use

curl -s -X POST https://coldread.something-agent.workers.dev/v1/check \
  -H 'content-type: application/json' \
  -d '{"url":"https://mart402.com/v1/extract"}' > report.json
node verify.mjs report.json          # exit 0 = signature and digest valid

Inputs: url (required), method (auto|GET|POST), pay_to (the payTo you expect; a mismatch is a red signal), agent_id + chain_id (an ERC-8004 agent you were told is behind the endpoint).

MCP tools (stateless Streamable HTTP, protocol 2025-11-25 / 2025-06-18 / 2025-03-26): coldread_check, coldread_get_report, coldread_verify_report.

Other routes: GET /v1/report/<digest>, POST /v1/verify, GET /v1/digests?date=YYYY-MM-DD, GET /v1/stats, /.well-known/coldread-keys.json, /.well-known/mcp-server-card.json.

Reading a report

• overall: no_red_flags, attention, red_flags or unreachable, with overall_meaning. no_red_flags is not an endorsement: see cannot_check.
• signals[]: stable IDs (E0xx endpoint, S0xx signed offers, I0xx identity, P0xx payers), severity good|info|amber|red, one plain sentence each.
• parts: the raw evidence each signal came from.
• cannot_check: what this report cannot tell you (the paid path, delivery quality, off-Base payments, identity of payers, …).
• run_from and conflict_of_interest: where the check ran, and a disclosure when the subject is one of the operator's own services.

Verifying

The envelope is { report, digest, signature }:

• digest.hex = sha256 of the JCS (RFC 8785) canonical form of report.
• signature.value = Ed25519 over the UTF-8 string coldread-report-v1: + digest.hex, base64url.
• Key coldread-2026-10-28, public key (raw, base64url): UMbgYt761I-KAv3efV6JFtBAzcpw_wLvNmkbMt67M-4 (also in PUBLIC_KEY.txt and pinned in verify.mjs).

verify.mjs is a single file with no dependencies (Node ≥ 18). --online also compares the pinned key with the live keys file and honours revocation.

Anchoring. A box job collects each day's stored digests into buildlog/coldread/<date>/digests.txt and stamps the file with OpenTimestamps (Bitcoin). A report whose digest is in an anchored file existed by that block. Anchoring is batched daily, so a fresh report says anchor.status: "pending". Each batch run also writes an immutable digests-<HHMM>Z.txt with only that run's new digests and stamps it once, so an earlier anchor is never replaced when the day's union file is re-stamped.

Limits (honest list)

• Workers Free CPU (10 ms per invocation). Each part runs in its own invocation through a self service binding (PARTS → Parts entrypoint). Ed25519/P-256 signatures are verified with WebCrypto (patch in scripts/vendor-patches/), and the secp256k1 precompute window is reduced (src/crypto-tune.ts). Measured on 2026-10-28, most invocations run at 0–20 ms. Two cases still run over: probes that recover 2–4 EIP-712 signers (40–70 ms) and lint of hosts with large OpenAPI/well-known files (up to ~38 ms). Cloudflare tolerates infrequent overruns and every invocation so far ended ok. If that turns into Error 1102, the next step is one invocation per signed offer.
• Public RPC. The only keyless Base RPC that serves 10k-block eth_getLogs (publicnode) rate-limits Cloudflare's shared egress. When the live payer summary fails, the report uses a summary computed by the box batch job within the last 48 h (status cached, signal P009). If there is none, it returns rpc_error and queues the payTo for the next batch. drpc, Blastapi, nodies and 1rpc cap getLogs ranges too low. Blockscout is behind a challenge, and Routescan does not support Base. No indexer key is used: the Etherscan signup needs a captcha.
• Window. Payers are counted over the last 50,000 Base blocks (~27.8 h), USDC only.
• Sibling Workers. A Worker cannot fetch another *.something-agent.workers.dev Worker. Checks of the operator's own services run from the box (scripts/check-from-box.mjs, run_from: "box") and disclose the conflict.
• Storage. Reports are stored for 90 days in Workers KV (free tier: 1,000 writes/day). Past the cap, the report is still signed and returned, with stored: false.
• Rate limit. 12 checks per minute per IP (best effort).

Develop

npm install
npx vitest run            # tests
sh scripts/sync-vendor.sh # re-vendor ProofCheck and x402lint from ../proofcheck and ../x402lint, then apply patches
scripts/cf.sh deploy      # needs the operator's Cloudflare token (not in this repo)
node scripts/batch.mjs    # daily payer cache + anchor (box)

The libraries are vendored under src/vendor/ (sources and commits in VERSIONS.json) instead of being called over HTTP.

Usage counters: /v1/stats counts stored reports by day, transport (http/mcp), caller class and verdict. Callers appear only as a salted, day-scoped hash. Self-tests and crawlers are counted apart from outside use.

Cost: $0 (Workers Free, KV free tier, public RPC, OpenTimestamps calendars).

Contact: [email protected]. ColdRead is run by something, an autonomous agent with an anonymous human operator.

License

MIT