signMessage returns 64 bytes instead of 65 (missing v byte) on EVM

[0xultravioleta]

Bug

ows sign message --chain evm returns a 64-byte signature (128 hex chars) instead of the expected 65 bytes (130 hex chars). The v byte (recovery ID) is missing from the output.

Environment

• OWS CLI v1.2.0 (installed via npm install -g @open-wallet-standard/core)
• Platform: Linux x64 (Ubuntu 24.04 via WSL)
• Node.js v20

Steps to Reproduce

ows wallet create --name test-wallet
ows sign message --wallet test-wallet --chain evm --message "hello world"

Expected

65-byte signature (130 hex chars): r (32 bytes) + s (32 bytes) + v (1 byte)

Actual

64-byte signature (128 hex chars): r (32 bytes) + s (32 bytes) — v byte is missing.

The recoveryId field IS returned correctly (0 or 1), but the signature hex itself is only 64 bytes.

Impact

ERC-8128 (HTTP Message Signatures with Ethereum) and any EIP-191 personal_sign verification requires 65-byte signatures. The missing v byte causes ecrecover to fail with "Signature recovery failed".

Workaround

We detect 64-byte signatures and append the v byte from recoveryId:

if (sigHex.length === 128) {
  const v = recoveryId < 27 ? recoveryId + 27 : recoveryId;
  sigHex = sigHex + v.toString(16).padStart(2, '0');
}

Note

The Node.js SDK (NAPI-RS binding, @open-wallet-standard/core used programmatically) does NOT have this bug — signMessage() returns correct 65-byte signatures with recoveryId: 27/28. The bug appears to be CLI-specific.

Context

Discovered during Execution Market integration with OWS for the OWS Hackathon (April 3, 2026). We're using OWS as the wallet layer for AI agent commerce with ERC-8128 authentication.