A GATE ledger is only evidence if you can check it yourself. This tool recomputes the hash chain and Merkle root and compares them to externally-anchored checkpoints — entirely in your browser. Nothing is uploaded anywhere.
Paste a ledger export and its anchored checkpoints, load the sample to see the mechanism, or pull Claire's own live record and read the external witness for yourself. A clean ledger verifies; alter any past decision and the check fails against the checkpoint an external notary recorded before the change. That's the difference between a log you're asked to trust and a record you can test.
A pass means the ledger you hold matches the head and Merkle root that an external anchor recorded — so nothing before those checkpoints was deleted, backdated, or softened without detection. It does not, by itself, establish that the anchor is trustworthy or that the ledger is complete; those come from the anchor's independence and the checkpoint cadence. Tamper-evident, not tamper-proof — and honest about the difference. The full protocol is documented in the Trust Anchor Protocol spec.