> ## Documentation Index
> Fetch the complete documentation index at: https://developers.circle.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Release notes - Agent stack - 2026

> 2026 release notes for Agent Stack

## July 2026

<Update label="2026.07.31">
  Launched the **Agent Marketplace**, a curated catalog of
  [x402](/gateway/nanopayments/concepts/x402)-compatible services that accept
  USDC. Every listing is sanctions-screened and health-checked, so agents find
  services that are compliant and live.

  Two new integration paths:

  * **Buyers (AI agents)** discover services through the public, keyless
    [Discovery API](/agent-stack/agent-marketplace/discovery-api)—`GET https://api.circle.com/v2/x402/discovery/resources`—with
    14 query parameters to filter by category, blockchain, price, and more. No API
    key or account required.
  * **Sellers (API owners)** list a service and get paid in USDC per call. See
    [Become a seller](/agent-stack/agent-marketplace/become-a-seller) for the
    nanopayments and vanilla x402 rails, or
    [Get listed](/agent-stack/agent-marketplace/get-listed) to submit a listing.

  Browse the live catalog at
  [agents.circle.com/services](https://agents.circle.com/services).
</Update>

## May 2026

<Update label="2026.05.12">
  Added documentation for Agent Nanopayments, which enables AI agents to make
  sub-cent USDC payments to x402-compatible services using Circle CLI.

  ### Documentation additions

  The following Agent Nanopayments documentation was created:

  * [Agent nanopayments](/agent-stack/agent-nanopayments)
  * [Quickstart: Make a nanopayment](/agent-stack/agent-nanopayments/quickstart)
  * [Nanopayment operations](/agent-stack/agent-nanopayments/operations)
  * [How-to: Withdraw your balance](/agent-stack/agent-nanopayments/operations/withdraw)

  ### Documentation updates

  The following how-tos moved from Agent Wallets into the new Agent Nanopayments
  section:

  * [How-to: Deposit for nanopayments](/agent-stack/agent-nanopayments/operations/deposit)
  * [How-to: Pay for a service](/agent-stack/agent-nanopayments/operations/pay-for-service)
</Update>

<Update label="2026.05.11">
  Launched Agent Stack, a new product line for AI agents to manage wallets,
  transact onchain, and pay for x402-compatible services using Circle CLI.

  ### Documentation additions

  The following Agent Stack and Circle CLI documentation was created:

  * [Agent stack](/agent-stack)
  * [Circle CLI](/agent-stack/circle-cli)
  * [CLI command reference](/agent-stack/circle-cli/command-reference)

  The following Agent Wallets documentation was created:

  * [Agent wallets](/agent-stack/agent-wallets)
  * [Quickstart: Create an agent wallet](/agent-stack/agent-wallets/quickstart)
  * [Agent wallet supported blockchains](/agent-stack/agent-wallets/supported-blockchains)
  * [Agent wallet fees](/agent-stack/agent-wallets/fees)
  * [Wallet operations](/agent-stack/agent-wallets/wallet-operations)
  * [How-to: Authenticate an agent wallet](/agent-stack/agent-wallets/wallet-operations/authenticate)
  * [How-to: Fund an agent wallet](/agent-stack/agent-wallets/wallet-operations/fund)
  * [How-to: Transfer USDC](/agent-stack/agent-wallets/wallet-operations/transfer)
  * [How-to: Bridge USDC](/agent-stack/agent-wallets/wallet-operations/bridge)
  * [How-to: Swap tokens](/agent-stack/agent-wallets/wallet-operations/swap)
  * [How-to: Deposit for nanopayments](/agent-stack/agent-wallets/wallet-operations/nanopay)
  * [How-to: Pay for a service](/agent-stack/agent-wallets/wallet-operations/pay-for-service)
  * [How-to: Execute a smart contract](/agent-stack/agent-wallets/wallet-operations/execute-contract)
  * [How-to: Sign a message](/agent-stack/agent-wallets/wallet-operations/sign)
  * [How-to: Set spending policies](/agent-stack/agent-wallets/wallet-operations/custom-policies)
</Update>