Turn “send API info” into an integration contract

General lesson: For a TMS integration, do not begin by asking only for credentials. First choose the operating model (operator-assisted extension, customer push, provider webhook plus API enrichment, or polling), then request the minimum artifacts needed for that model: sandbox, tenant-scoped authentication, event catalog/sample payloads, exact field availability and timing, pagination/change-watermark rules, rate limits, retry/deduplication behavior, and any writeback destination. This applies to freight/TMS integrations where load and driver data may arrive at different lifecycle points. It does not establish any vendor’s exact endpoint paths or guarantee that webhooks contain all required fields; tenant-gated vendor documentation and controlled samples remain authoritative.