> For the complete documentation index, see [llms.txt](https://docs.zetrix.com/en/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.zetrix.com/en/developer-resources/agentic-wallet/abstract.md).

# Abstract

The web learned how to ask for money before it learned how to ask *who you are*. HTTP received its payment status code (402 Payment Required) in 1997; it never received an identity one. x402 revived 402 to let servers charge autonomous agents for access. **x401**, introduced by Proof in June 2026, is the identity counterpart: a challenge-response protocol layered on HTTP 401 Unauthorized in which a server requires an agent to present a **cryptographically verifiable proof of identity or authority**, that a real, verified human (or a legitimately standing organization) authorized the action, *before* granting access.

This paper specifies how the **Zetrix Agentic Wallet** implements x401 as a native capability, reusing the same wallet service that already speaks x402. It maps the x401 challenge/presentation flow onto Zetrix's existing decentralized-identity stack (ZID Verifiable Credentials, BID-method DIDs, on-chain credential registries), defines the concrete message formats, and shows how x401 (authority) and x402 (payment) compose into a single **full agentic transaction**: *prove who authorized you, then pay, then act.* Version 1.0.0 reconciles the paper with the approved design and architecture.