WIWhat is the agent economy?

A working definition

The agent economy is the set of transactions in which a software agent discovers a service, agrees to pay, or pays, instead of a person clicking through a checkout each time. The agent can be a language-model loop with tools, a narrower script, or another company's agent calling an API. The payer of record may still be a person or a firm. What changed is who drives the request.

That definition is deliberately wider than any one protocol. x402 is a way to pay for an HTTP resource. MPP is a way to meter a session. AP2 is a way to authorize an agent to buy. ACP is a way for a merchant to check out inside an assistant. L402 is a way to pay a Lightning invoice for an API. They are all agentic commerce. They do not produce one comparable ledger.

Agent GDP uses a narrower definition, on purpose. It sums settlements this index can attribute from public chain data, and it leaves everything else visible but uncounted. The current total is below. It is the same rollup as the Agent GDP page, cached for about five minutes.

Agents, tools, and payments are different layers

An AI agent is software that pursues a goal by calling tools. The Model Context Protocol is a common way to expose those tools. A2A is a way for agents to message each other. Neither protocol moves money. A tool call is not a payment, and a payment is not evidence that the caller was a language model.

ERC-8004 is a registry for agent identity, reputation, and validation. It reserves an agentWallet field for where a registered agent gets paid. Registration does not settle funds, and this index does not read the registry in order to decide which transfers count. The settlement rule stands on its own.

Keeping the layers apart is what makes the number citeable. If conversations, mandates, and transfers were added together, a purchase that used all three would be counted three times. The measurement page states the rule. This page is about what the economy contains.

Five protocols, two ledgers

Two of the protocols leave a public settlement this index reads today.

• x402 uses HTTP 402. A facilitator verifies a signed payment and settles it, usually in USDC, on chains such as Base, Polygon, Solana, and Arc. The observable row is the token transfer.
• MPP sessions on Tempo lock a deposit in an escrow channel. The client signs vouchers. The server settles the consumed amount. The observable row is the Settled event's deltaPaid.
• AP2 signs checkout and payment mandates. The mandate authorizes a purchase. The funds move on some other rail, which is counted only if that rail is already indexable.
• ACP runs a merchant checkout session inside an agent. The merchant charges its own processor. OpenAI's documentation says OpenAI is not the merchant of record. There is no public feed of those captures.
• L402 pairs HTTP 402 with a Lightning invoice and a macaroon. The receipt is a preimage. Invoices are not one global log.

What the payments are for

The Bazaar catalog, which this index crawls, describes x402 resources in plain language: model inference, search, page fetching, data lookups, prices, media, and agent tools. Those descriptions become the use-case categories. A category total is settled volume whose payee matched a classified resource. It is not a survey of what agents might pay for.

Unclassified volume is real settlement that did not match the catalog. It stays in Agent GDP and stays out of the named categories. Coverage, the share of volume that did match, is printed on the use-case pages so the gap is visible.

What this site does not claim

It does not claim the buyer was an autonomous agent. The buyer is an address on a transfer or a Tempo event. It does not claim organic volume is free of wash trading. The organic screen is a published filter, and it misses related parties. It does not convert catalog list prices into volume. Only settled amounts enter the total.

It also does not pick a winner among the protocols. A metadata row at zero is not a judgment that the protocol is unused. It is a statement that there is no public, attributable settlement to sum. When a feed exists, the way to add it is an adapter, described in the project docs, not a guess on this page.