Queries and x402

A buyer asks a question in plain words over one or more kinds, and says how many negatives the answer should read.

Price. 0.01 USDC per 100 negatives read: a query reading n negatives costs ceil(n) × 100 micro-USDC. A model call costs 0.002 USDC.

The flow.

1. POST /api/query with {"kinds":[…],"question":"…","negatives":n}.
2. If the room cannot answer, it refuses before any charge: 422 below the floor of 25, 409 when it holds too few negatives of those kinds.
3. Otherwise it answers 402 Payment Required with x402 requirements: scheme exact, network solana, asset USDC, payTo the room's treasury, maxAmountRequired the price.
4. The buyer signs a USDC transfer for that amount and repeats the request with the X-PAYMENT header.
5. The room checks the transfer, runs the query inside the room, and answers with the result and a signed receipt.

Settlement opens with wave 1; until then step 3 is as far as a query goes, and nothing is ever charged.