Date: February 11, 2026

If you want paid tool calls without subscriptions, treat payment as control flow:

1. Call endpoint
2. Receive HTTP 402 with Lightning invoice
3. Pay under a strict sats cap
4. Retry with proof

Live references:

• https://wot.klabo.world/pricing
• https://maximumsats.com/api/dvm

Why this matters for agents:

• explicit spend budget
• deterministic retry behavior
• receipt trail for auditing

Question: what is the missing client abstraction to make 402->pay->retry default in agent frameworks?