Guard external costs

Your app fee is one line among several. Provider and network costs are others — reconciled the same way, and worth guarding before they surprise you.

1. 01 · Read every cost line

   A transfer's cost is not one number. Alongside your app_fee sit platform_fee, provider_fee, and gas_fee — each a line, each in the same unit.

   fees.lines[].kind ∈
     app_fee · platform_fee · provider_fee · gas_fee

2. 02 · Decide who bears them

   The bearer on the instruction decides whether external costs come out of what lands or sit on top. Quote first: the quote returns the lines before you commit, so a cost is never a surprise at settlement.