AGTP Transparency Log Protocol

This document specifies the AGTP Transparency Log (AGTP-LOG): the append-only audit log protocol that underpins the log-anchored Trust Tier 1 verification path defined in [AGTP] and provides the post-hoc audit infrastructure for AGTP-based agent operations. AGTP-LOG aligns with [RFC9162] (Certificate Transparency 2.0) as the verifiable data structure and issues COSE_Sign1 receipts per [RFC9943] (SCITT) for cross-ecosystem interoperability. This document also establishes the AGTP Agent Identity Taxonomy (Agent Genesis, Canonical Agent-ID, Agent Certificate) that [AGTP] v07 normatively adopts. The log protocol defined here covers entry submission, receipt retrieval, inclusion-proof retrieval, consistency-proof retrieval, and discovery via the log_uri field of the Agent Genesis. Per-platform logs are the default; the federation model follows the SCITT cross-witnessing pattern. Witness and monitor role definitions, full federation procedures, and the formal entry-acceptance threat model are deferred to a future revision. The audit properties AGTP-LOG provides are structural rather than retrofitted. Statements are signed by the governance platform that operates the log, not by the agent the statements concern; an agent cannot forge its own audit trail because it does not control the log operator's signing key. This architectural separation distinguishes AGTP-LOG audit infrastructure from approaches that layer audit data models onto general-purpose substrates where the audited party participates in writing the audit trail.