Card networks vs open protocols: who controls agentic commerce

Two layers, not one fight

It is tempting to read agentic commerce as a standards war. It is not. The protocols and the networks operate at different layers. A protocol like ACP or UCP standardizes the conversation between an agent and a merchant. A network like Visa or Mastercard provides acceptance, settlement, tokenization and dispute rights underneath that conversation. The interesting question of 2026 is not which protocol wins, it is who captures the value as the protocols proliferate. The networks have a clear answer: they intend to be the layer every protocol settles through.

What the networks shipped in June 2026

On 10 June at the Visa Payments Forum, Visa expanded Visa Intelligent Commerce, its platform for agentic commerce, with three capabilities: Agent Score, which lets a merchant test whether agents can complete tasks on its site, an Agentic Directory that acts as a trust registry of legitimate agents, and a Large Transaction Model that applies AI to authorization. Visa also added stablecoin settlement. Hours later it announced a partnership with OpenAI to put tokenized Visa credentials inside OpenAI experiences.

The same day, Mastercard launched Agent Pay for Machines, a service to settle agent-to-agent payments and microtransactions at machine speed, with more than 30 partners. A week later, Adyen launched Adyen Agentic and called it a universal translator: one integration, every agent platform and protocol. Three different companies, one strategy.

Why protocol-agnostic is the strategy

For a merchant, betting on a single protocol is a risk, because surfaces churn. OpenAI itself retired its first Instant Checkout flow in early 2026 before rebuilding it on Shopify’s agentic stack. A network that accepts agents across ACP, UCP, AP2 and x402 at once removes that bet. That is exactly what Visa, Mastercard and Adyen are selling: not a protocol, but indifference to which protocol the agent speaks. Google, for its part, is reinforcing the open layer, arguing at the Open Source Summit that commerce needs shared, open rails. The two moves are compatible: open protocols for interoperability, networks for acceptance.

Trust is the moat

The deeper play is trust. Anyone can implement an open protocol, but only the networks can say, with their existing rails and dispute systems, that a given agent is verified and a given payment is authorized and protected. Visa’s Trusted Agent Protocol, Agent Score and the Agentic Directory all point at the same question a regulator would ask: is this agent who it claims to be, and did a human authorize this spend. That is the part a protocol cannot manufacture on its own, and it is where the networks are concentrating.

What it means for merchants

The conclusion has not changed, it has hardened. Make your catalog and checkout legible to agents through a commerce protocol, then accept them through a processor that already spans the networks and protocols, rather than picking a single standard. Start with the standards comparison and the card-network view in Visa TAP vs Mastercard Agent Pay, understand the full agentic payments stack, and see how to accept payments from AI agents. For the month that made all of this concrete, read the June 2026 roundup.