Deal lifecycle is not a salesperson UX flow. A deal advances stage if and only if a corresponding real-world handshake is signed and captured by the chain (H1 → H2 → H3a → H3b → H4). The commission engine consumes those signed events, advances the deal’s lifecycle state, and writes the ledger. The CRM renders that progression for human eyes — it never originates it.

Why it matters: This is what makes Flip360 fundamentally different from Salesforce/HubSpot/Pipedrive. In those tools the salesperson clicks "Move to Won" and the deal is Won. In Flip360, a deal is Won because the customer signed H4 — and nobody, including the salesperson, can make a deal Won without that signature. The handshake chain IS the source of truth. Without it, no $248M exit thesis.

When two tools talk, they use a named, repeatable, idempotent seam (S1–S8). Each one has a contract: producer, consumer, payload, failure mode. New features can’t just "call into" another part — they go through a known seam.

Why it matters: This is what stops the system getting messy as we scale. The EA function (Claude under delegation) enforces this.

Whenever "easier UX" fights with "preserves audit trail," audit trail wins. Always. The handshake chain isn’t decoration — it’s why this thing survives disputes, regulator queries, and exit due-diligence.

Why it matters: Flip360 is a regulated money system (FASEA, ATO RCTI, Pine Lawyers) built for a $248M exit. Trade audit trail for UX once = destroy the exit thesis.