A2A capability discovery does not grant payment authority.

The older A2A page advertised x402/1.0 and XRPL-oriented payment headers. Those instructions are retired from current ScriptMasterLabs authority.

Current rule

Discover the selected capability, call its exact target resource, read the fresh PAYMENT-REQUIRED challenge, and let the caller decide whether to create the matching PAYMENT-SIGNATURE.

Current SML paid-resource defaults are Base mainnet eip155:8453 and USDC. A 402 challenge or signature is not settlement proof.

Current agent card → · Current x402 discovery →

Part of the agentic payments cluster

This page’s job: agent-to-agent payment semantics — the narrow question of what A2A discovery does and does not authorize, and which legacy payment instructions ScriptMasterLabs has retired.

How do AI agents pay for APIs? — the canonical overview of how agents pay, end to end.

A2A discovery meets x402 machine commerce — the live SML bridge that implements this semantics.

A2A capability discovery does not grant payment authority.

Part of the agentic payments cluster

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