VerityLayer verifies whether a factual claim is true — fact-check, verify a claim, is this true. Independent, fail-closed verification for AI agents: returns a verdict (supported/unsupported/uncertain), a calibrated 0-1 confidence, reasoning, and evidence; abstains rather than guess. Every verdict includes an Ed25519-signed receipt — portable cryptographic proof of what was verified, free re-verification at /receipt/verify. Tier: grounded — live web citations (Sonnet, default).