POPCORN Witness Verifier MCP server

767-2676.com — signed task schedule checkpoints for agents

Looking for RFC 3161, FreeTSA, OpenTimestamps, a trusted timestamp, proof of existence, authorization expiry, a signed execution receipt, or independent verification? Start with Proving an action happened before an authorization expired.

Licensing: component boundaries and earlier grants · evaluation terms · receipt carry-and-use permission. The paid service is separate from code permissions.

Live pages: POPCORN homepage (source and SOS 1.2.0 notes) and Check the assumptions (source, build and verification checks). The assumptions page presents saved signed task checks in human language and machine-readable form. Its PROCEED and STOP results describe historical local policy, not current authorization or execution.

Run the verification checks yourself

Offline checker and instructions: 37 cases covering schedule boundaries, malformed input, exact bytes, and saved signed receipts. From this repository with Node.js 20+:

node examples/verification-checks/check.mjs

No wallet, payment, or network call. Expected results are separate from computation. These checks establish code behavior and historical verification, not live authorization or execution.

Here, try your free sample

Can I still cancel? Which side of the deadline am I on?

Inspect the page. Save and read sample.mjs, then run node sample.mjs with Node.js 20 or newer. No key, wallet, or payment for this offline sample.

Expected results: verified: true, digestmatches: true, and onebytewhotamper_rejected: true. This is a 305-byte task schedule with historical evidence; it does not establish current time or authorization.

Agent instructions · Take the packet home · Hugging Face

The older 228-byte checkpoint example below is a separate demonstration.

POPCORN is Briarwood AI's service for signed time and digest witnesses. Use it when independent agents need timing evidence for a deadline, a handoff, or one exact task version. Each participant retains its raw task data and decisions.

A note is not a check. These 228 bytes are.

Start with the settled public packet. It lets a human or agent verify the signature, compare the signed witness interval with the execution window, and prove that one changed byte breaks the digest. It is free, offline, and requires no wallet.

POPCORN also operates a live, machine-payable temporal evidence service at 767-2676.com. A wallet-enabled agent can pay $0.001 USDC over x402 v2 for a new signed temporal receipt when a later live task actually needs fresh evidence.

The live node also provides the tested POPCORN-WITNESS/2.0 contract for a payload-bound checkpoint: a lightweight way for an autonomous agent to carry portable, verifiable evidence that one exact task-state commitment reached an external witness without putting its private task state in a shared database. That additive endpoint is deployed, paid through x402 on Base mainnet, and independently verified in both JavaScript and Python.

Shortened. The full README is on GitHub.