Circle unveiled Circle Agent Stack, an open infrastructure designed to help build AI agents that can function as autonomous economic entities.
Circle announced Agent Stack as a set of tools for creating autonomous AI agents capable of holding funds, paying for services, and executing transactions in USDC without human intervention. The solution is aimed at the emerging agent economy, where software systems independently interact and conduct real-time payments with each other.
According to Circle, the new infrastructure addresses one of the key challenges in the AI agent market — the lack of a secure and efficient financial system for machine-to-machine transactions.
The platform includes several core components:
- Agent Wallets. Wallets for AI agents with flexible controls, allowing users to set spending limits, whitelist and blacklist addresses, and define transaction approval rules.
- Agent Marketplace. A platform for discovering and connecting services that agents can use autonomously.
- Circle CLI. A command-line interface for managing wallets, settings, and payments through precise commands.
- Circle Gateway. A USDC micropayment mechanism enabling gas-free transactions for frequent and low-value payments.
- Circle Skills. A set of templates and tools for AI application developers.
According to Circle, as of April 29, the x402 protocol, designed for agent-to-agent payments, processed $24.24 million in transactions over the past 30 days, with 99.8% of settlement volume conducted in USDC.
The company believes that the growth of such systems requires dedicated financial infrastructure capable of supporting:
- real-time programmable payments;
- high-speed transaction processing;
- large-scale micropayment flows;
- unified interoperability between services and blockchains.
Circle emphasizes that Agent Stack is open and not tied to any specific blockchain or protocol. Developers can define agent behavior rules, select services, and set financial constraints independently. Some components, including Circle Skills and a reference implementation of nanopayments via Circle Gateway, are already available as open-source tools.
The company also noted that before Agent Stack, developers had to rely on fragmented solutions — manually managing keys, integrating disconnected APIs, and building custom authorization systems. The new stack aims to unify these processes into a single infrastructure where AI agents can securely store funds, discover services, and automatically execute payments through standardized tools. The platform also supports the CCTP, enabling USDC transfers across different blockchains.
