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

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, digest_matches: true, and one_byte_who_tamper_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/1.0 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.

The service is intentionally narrow. It provides evidence for participant-local judgment; it does not schedule work, reserve resources, authorize actions, or store an agent's private task state.

Lab record

On 31 August 2026, Grok and Codex coordinated one live payment using only text I copied and pasted. The record documents the exact bytes, settlement, approval, and refusal.
Read the lab record and verify the packet.

• Production node: 767-2676.com
• Paid resource: GET https://767-2676.com/v1/time
• Paid witness: POST https://767-2676.com/v1/receipt
• Payment: $0.001 USDC on Base mainnet (eip155:8453)
• Protocol: x402 v2, exact scheme
• Receipt: ES256 compact JWS with public JWKS verification

Start here

The MCP connector includes a free evaluation of both historical production receipts. To run it from this repository:

git clone https://github.com/violetclaire/popcorn-temporal-anchor.git
cd popcorn-temporal-anchor/packages/mcp
npm ci
npm run build
node dist/packages/mcp/src/index.js --sample

After version 0.1.2 is published to npm, the same evaluation is one command:

npx -y @violetclaire/popcorn-mcp@0.1.2 --sample

It verifies both bundled historical production receipts and rejects their one-byte tamper controls. After installation, the evaluation is fully local and needs no wallet. A connected MCP agent can call popcorn_sample with {} for the same check. See the connector guide for installation and choosing a tool for deadlines, task versions, or handoffs.

Run the checked-in STOP packet before making any network or payment call:

node --disable-warning=ExperimentalWarning --experimental-strip-types examples/witness/verify-settled-sample.mjs

Expected result:

cryptographic_verification=valid
schedule_overlap=false
local_policy_outcome=stop
error_code=witness_payload_digest_does_not_match_expected

The command imports the reusable TypeScript verifier, checks the exact 228-byte schedule, applies the published one-byte mutation at offset 226, and exits zero only when the valid packet and failed digest control both behave as expected. It does not call 767-2676.com or any payment endpoint.

Open the human version at /demo. Its publish-ready source is in site/demo, and the deployment handoff is in OPERATOR.md.

Agents can install the same sample-first instructions from either desk:

openclaw skills install @violetclaire/popcorn-temporal-anchor
npx skills add violetclaire/popcorn-temporal-anchor --skill popcorn-temporal-anchor

The public machine door remains https://767-2676.com/SKILL.md.

Available service

POPCORN says what time it is. The agent carries that measurement in its own schedule. POPCORN does not store the task or schedule and does not decide what happens next.

Portable, verifiable state checkpoints

Your agent already carries task state. What it lacks is portable evidence that one exact version reached an external witness within a stated time window.

The live paid resource is:

POST https://767-2676.com/v1/receipt

The agent hashes the exact payload bytes locally and sends only:

• the SHA-256 payload digest;
• a fresh 32-byte nonce;
• optionally, the SHA-256 digest of the preceding receipt's exact signed payload bytes.

POPCORN signs those values with a bounded witness interval. The agent carries the original payload and signed evidence together. A later session or another system can verify that the payload has not changed, when the node witnessed its commitment, and whether the evidence commits to a specific predecessor.

The receipt alone is not memory: it cannot reconstruct, retrieve, understand, or act on the payload. It also does not prove caller identity, recipient delivery, action execution, replay prevention, or authorization. Read the full POPCORN-WITNESS/1.0 contract.

Verify two settled production outcomes

The original checked-in evaluation-packet.production.json remains unchanged. Its cryptographic verification succeeds, but its checkpoint falls after the schedule closed, so the example consumer policy says STOP. The companion evaluation-packet.proceed-002.production.json also verifies and rejects a one-byte tamper, while its checkpoint overlaps the schedule window, so the example consumer policy says PROCEED. The machine-readable evaluation-outcomes.json states the local overlap rule and both expected decisions.

Each packet contains exact schedule bytes, a SHA-256 digest, nonce, settled production response, public key, successful cryptographic result, and a one-byte tamper case that must fail. They contain no private key, CDP credential, wallet secret, reusable payment proof, or private customer data. evaluation_only: true is outside the signed payload, so each production JWS remains unchanged. POPCORN proves the checkpoint; the consumer applies its own schedule policy and decides whether to proceed.

The reusable verify/typescript and verify/python packages independently implement the witness contract. The production packet records the reproduced success and one-byte failure results, and the original deployment test logs remain outside this public repository.

Carry a schedule between two computers

The typescript-x402-witness-client now accepts an exact schedule file or HTTPS URL instead of inventing a built-in example. It hashes the bytes, pays for the checkpoint, captures the x402 exchange, verifies the live POPCORN key, and writes a portable outcome JSON. A separate command on another computer downloads that outcome and recalculates everything without trusting the producing client's conclusion.

The deterministic result is one of:

• STOP when the complete signed witness interval is outside the schedule;
• TIME_CHECK_PASSED when the complete interval is inside the schedule;
• RECHECK when clock uncertainty crosses a schedule boundary.

Every result includes authorization_granted: false. Passing the time check never grants permission or claims that work was performed. The schedule bytes travel through the participants' chosen transport; POPCORN receives only their digest and never becomes the schedule database.

The full carrier and verifier test suite uses the already settled packets, so development and independent reproduction require no new payment. A new paid checkpoint is needed only when an agent needs fresh production evidence.