Buyer proof · Locus-compatible standalone

Preflight a dynamic Base payment target before the agent pays.

This original Node adapter observes the payment.to address selected at runtime, applies a caller-defined evidence policy, and only then invokes a payment callback. It is a clearly labelled Locus-compatible standalone example, not a Locus integration or partnership.

The boundary in four steps

1 · SelectAn agent chooses a Base contract and payment payload dynamically.

2 · ObserveM2M Sentinel audits that exact payment.to address.

3 · PolicyThe caller blocks missing evidence or unresolved delegation.

4 · PayThe Locus-style payment callback runs only after allow.

A DELEGATECALL_PROXY_SUSPECTED response with resolutionComplete: false is visible to the policy and stops the payment callback.

Run it without a wallet

From a checkout of the M2M Sentinel repository with Node.js 22+:

node --experimental-strip-types examples/proofs/locus-compatible-agent-payment.ts --target=0x1111111111111111111111111111111111111111
node --experimental-strip-types examples/proofs/locus-compatible-agent-payment.ts --unresolved

The first command uses a deterministic mock payment client. The second exits non-zero with PROXY_OR_DELEGATION_UNRESOLVED and does not call it.

Expected evidence

policy: ALLOW
LOCUS_COMPATIBLE_PAYMENT_EXECUTED (mock only; no wallet or funds)
resolutionComplete: true
reachability: NOT_ESTABLISHED
notASafetyGuarantee: true

The callback returns NOT_SUBMITTED. Replace it with the buyer's own payment client only after keeping the preflight and policy boundary.

Optional live observation

Set M2M_SENTINEL_API_KEY locally and run --live --target=<base-address>. The key is sent in the x-api-key header and never in a URL. The payment callback remains a mock, so no funded wallet or real payment is needed. 401, 402, 503, network errors, invalid JSON, and unresolved evidence all fail closed.

Source example Official Locus documentation Official Locus developers page Request a bounded sprint handoff

The public references describe Base smart-wallet, scoped-policy, and pay-per-use concepts. This page does not claim a Locus partnership or official integration.

Limits

Static capability evidence is not a safety, maliciousness, exploitability, authorization, or reachability verdict.
The caller owns the allow/block policy. This example chooses to block when proxy or delegated execution is unresolved.
The example intentionally does not use a Locus SDK or copy upstream code; adapt the callback to the current public integration surface you have reviewed.