Custody is
constraint design.

Custody is not only an exchange or wallet problem. In payment systems, custody boundaries decide where money can pause, who is allowed to release it, and how much blast radius a failed flow can create.

• Where value waits before settlement is a custody decision.
• Approval timing changes product behavior, not just operations.
• Failure containment depends on how custody boundaries are drawn.

Stablecoins do not simplify custody. They shift it into reserve design, redemption logic, treasury controls, internal liquidity routing, and settlement timing.

• Reserve movement becomes part of the control model.
• Redemption and treasury flows reshape operational risk.
• Stablecoin settlement still depends on timing, liquidity, and governance.

• MPC reduces key concentration risk.
• Traditional keys can simplify operational coordination.
• Control gains often come with coordination cost.
• Human failure and system failure must be modeled separately.

1. Custody systems fail silently if designed poorly.
2. Good design assumes incidents will happen.
3. Recovery paths matter more than happy paths.