POPCORN Temporal Anchor

Obtain and verify paid, signed temporal evidence before a time-sensitive cross-node action.

Use POPCORN when a wallet-enabled agent must support a time-sensitive local decision with portable evidence another node can independently verify.

Canonical paid resource:

text

GET https://767-2676.com/v1/time

The resource costs $0.001 USDC through x402 v2 on Base mainnet (eip155:8453). It returns an ES256-signed, short-lived temporal receipt.

Why this skill is open

POPCORN is a voluntary interoperability pattern, not a mandate and not a central authority. This skill publishes one working method for discovery, payment, verification, freshness, and expiration so independently operated agents do not have to recreate incompatible coordination logic.

An agent may use the canonical temporal node at 767-2676.com, implement compatible verification locally, or decline to use the protocol. No adoption is required, and POPCORN never takes control of participant-local decisions or state.

Build compatible implementations, not confusing replicas. Independent nodes are welcome, but each node must identify itself honestly with its own node_id and verification keys while preserving the shared receipt and verification contract. Copying the surface while changing identity or receipt semantics fragments discovery and trust and recreates the coordination problem POPCORN exists to reduce.

Open reuse of this skill does not make a copied endpoint a canonical POPCORN node. Treat temporal evidence as POPCORN evidence only when its signature verifies against https://767-2676.com/.well-known/popcorn-keys.json and its signed payload identifies node_id as 767-2676.com. Publication of this skill under MIT-0 covers this reusable skill text and its instructions; it does not provide access to or control over the domain, operated service, signing keys, receiving wallet, or Briarwood systems.

Before paying

1. Read the current service offer: https://767-2676.com/agent/offer.
2. Read the canonical execution contract: https://767-2676.com/SKILL.md.
3. Confirm the task has an execution_window_utc and participant-local policy authorizes the payment.
4. Select a compatible entry from PAYMENT-REQUIRED.accepts; never assume accepts[0] is compatible.
5. Require PAYMENT-REQUIRED.resource.url to equal https://767-2676.com/v1/time. Do not pay a copied or redirected resource.

Execution

1. Start a monotonic timer for the paid retry.
2. Send the x402 PAYMENT-SIGNATURE retry to the exact challenged resource URL.
3. Record response receipt with the same monotonic timer.
4. Require HTTP 200, PAYMENT-RESPONSE, and a JSON temporal receipt.
5. Verify temporal_attestation.compact_jws using the matching kid from https://767-2676.com/.well-known/popcorn-keys.json. Reusable network-free verifiers and a shared signed vector are published at https://github.com/violetclaire/popcorn-temporal-anchor/tree/main/verify.
6. Decode the verified JWS payload and require node_id to equal 767-2676.com and protocol_id to equal POPCORN/1.0. Treat any other identity or key origin as a different service, not POPCORN.
7. Validate all signed timing relationships and compute the conservative uncertainty envelope exactly as defined by the canonical skill.
8. Compare that entire interval with execution_window_utc.
9. Continue, wait, obtain a fresher anchor, or terminate according to local policy. POPCORN evidence is not a command.

Boundaries

• The receipt is bearer evidence: portable, not caller-bound, and not task-bound.
• The receipt grants no authorization and proves no identity.
• task_payload, schedules, availability, pricing, callbacks, trust state, and outcomes remain participant-local.
• Do not send private task state to 767-2676.com.
• The Briarwood Agent Blueprint is machine-node implementation architecture only; it has no dependency on a separate consumer-facing Briarwood system.
• Fail closed if payment, signing-key verification, timing validation, or the local execution-window decision cannot be completed.
• POPCORN is not an A2A server or MCP server. An agent using either protocol may call the x402 HTTP resource and apply the verified evidence locally.