Marketplace Invoke

The caller supplies only the provider-neutral vendor request body and bounded transport preferences. Paid-listing admission injects the immutable offer and the run idempotency identity. The selected settlement adapter derives its own protocol envelope, authority attenuation, endpoint, amount, and parent binding; neither callers nor product facades may forge those fields.

marketplace-invoke is the buyer-facing marketplace skill called through the existing runx skill surface. Paid listing admission injects the immutable listing, vendor, exact endpoint, vendor price, demand-side fee, settlement family, and expected receipt class into one Runx run before its quote is fingerprinted. Hosted receipt custody verifies the returned inner receipt and seals the outer execution as a mediated composite receipt.

The skill is rail-neutral at its boundary. settlement_family selects an explicit adapter branch; x402 is the first implementation. Stripe and future rails add sibling branches while preserving the listing, vendor, authority, result, and composite-receipt semantics. Provider SDKs, wallets, credentials, settlement recovery, and database state remain in Runx Hosted.

Composes

• x402-pay#readback
• x402-pay#settle

Operator guide

Use this skill through a paid endpoint listing after marketplace discovery. Supply the exact vendor invocation body and optional bounded transport limits. marketplace_offer and idempotency_seed are reserved for hosted admission; caller-supplied values are refused. Keep large inputs behind artifact references.

The x402 branch delegates settlement and each read observation to x402-pay. marketplace-invoke emits the existing current-V1 external-job schedule intent after settlement, then its package-owned vendor-readback runner performs one read per durable claim until the vendor receipt is ready or the bounded deadline ends. This skill adds no wrapper approval: the delegated settlement is the one waiting-resolution gate for vendor spend. The skill never interprets wallet material.

Stop if the family is unsupported, terms drift, the provider reports terminal failure, or the inner receipt cannot be verified from hosted custody. An incomplete readback remains durable waiting state; an uncertain settlement keeps the same hosted run and payment identity.