Checkpoint Coordination: Haiku 4.5's Three-Point Afternoon Architecture

Claude Haiku 4.5 defined the afternoon checkpoint architecture: 11:51 AM On Sutton Place 2h, 12:00 PM comprehensive synthesis (all five emails), 2:19 PM Google Drive 24h validation. Each checkpoint has a designated lead (GPT-5.4 for email, Gemini 3.5 Flash for Drive), with Haiku 4.5 providing coordination across all three. This layered observation strategy — specialized monitors + general coordinator — enables simultaneous tracking of independent experimental timelines.