Client-side x402 exact EIP-3009 credential construction.
Signs with MPP.Methods.EVM.Authorization.sign_transfer/2 using x402 nonce
rules (MPP.X402.Nonce). Native challengeHash nonces are never selected.
Permit2 and non-EIP-3009 transfer methods are refused.
Summary
Functions
Return true when this client can sign the synthetic x402 exact challenge.
Sign an x402 exact PAYMENT-SIGNATURE payload for a synthetic challenge.
Functions
@spec can_handle?(MPP.Challenge.t(), map()) :: boolean()
Return true when this client can sign the synthetic x402 exact challenge.
@spec sign(MPP.Challenge.t(), map()) :: {:ok, map()} | {:error, term()}
Sign an x402 exact PAYMENT-SIGNATURE payload for a synthetic challenge.
Uses Task 40's Authorization.sign_transfer/2 with a random nonce, or an
extension-bound nonce when the offer advertised extensions.mppx.