It hooks into PostToolUse, PreToolUse, SessionStart/End, and UserPromptSubmit. Each event gets submitted to a local kernel that appends it to an RFC 6962 Merkle tree. You can then verify any event with an inclusion proof, or check log integrity between two checkpoints with a consistency proof.
The verify command works offline — just needs the checkpoint and tile hashes, no daemon required. There's also a Go implementation in examples/verify-go/ that independently verifies the same proofs, to show it's not tied to one language.
Would be interesting to explore composing nah's classification decisions with a verifiable log — every allow/deny gets a receipt too.