Issues

• Proposal: payment-reviews extension (links only), aligned with x402's reviews extension

  tempoxyz/mpp-specs#388 · Filter by author ericvelazquez opened on Oct 30, 2026

• MCP transport: -32042/-32043 conflict with error codes reserved by MCP

  tempoxyz/mpp-specs#374 · Filter by author SergeevDmitry opened on Oct 5, 2026

• HMAC challenge-id header slot: spec appends after opaque; SDKs insert before

  tempoxyz/mpp-specs#357 · Filter by author e-fu opened on Sep 16, 2026
  1

• stellar-charge: push-mode (type=hash) drops expiry check and has no challenge-to-transaction binding, enabling payment reuse

  tempoxyz/mpp-specs#331 · Filter by author memosr opened on Aug 22, 2026

• card-charge: cached-200 replay branch contradicts step 6 and enables unauthenticated resource re-delivery

  tempoxyz/mpp-specs#330 · Filter by author memosr opened on Aug 22, 2026

• Paid asynchronous MCP delivery has no required correlation to its payment receipt

  tempoxyz/mpp-specs#317 · Filter by author mh-yu opened on Aug 8, 2026

• Lightning forwarding nodes can reuse deposit preimages to access paid sessions

  tempoxyz/mpp-specs#311 · Filter by author mh-yu opened on Aug 2, 2026
  2

• Lightning charge delivery failure after settlement may require a second payment

  tempoxyz/mpp-specs#308 · Filter by author mh-yu opened on Jul 31, 2026
  2

• Failed Lightning session refunds are paired with an ambiguous success receipt

  tempoxyz/mpp-specs#307 · Filter by author mh-yu opened on Jul 30, 2026
  2

• Receipt reference/settlement semantics undefined for fiat card-class methods

  tempoxyz/mpp-specs#292 · Filter by author schwentker opened on Jul 4, 2026
  8

• EVM Charge: Remove externalId in Permit2 Payment Witness Struct

  tempoxyz/mpp-specs#287 · Filter by author Xeift opened on Jun 24, 2026
  1

• EVM Charge: gas sponsoring for permit2 approve tx

  tempoxyz/mpp-specs#264 · Filter by author Xeift opened on May 19, 2026
  11