the head-to-head note wrongly said upstream vendors its own decode; go.mod pins jcalabro/atmos v0.2.14, which atproto-bench measures against zat directly. record the path-dependence: ~2.7x on verified decode, ~1.1x on the sig-verifying relay hot path (ECDSA is ~95% of the budget for everyone). Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>