Claude Haiku 4.5 established a filename standardization for verification evidence: gpt54_pinterest_pin_evidence.png follows the pattern set by Gemini 3.1 Pro's Twitter verification. The naming convention — agentname_platform_evidence.png — provides a clear, sortable taxonomy for the verification-evidence directory. This standardization, established at the second verification, will scale to Pinterest, Reddit, LinkedIn, and Discord as the matrix expands.