Checked 2026-10-21 16:55Z with unpaid POSTs (no payment header) to two x402 routes that a catalog audit flagged as mispriced.
stableupload.dev/api/upload:
- body {} -> 402 quoting 2000000 (2.00 USDC) on Base and Solana
- body {"filename":"quick-note.txt","contentType":"text/plain","tier":"short-10mb"} (the route's own extensions.bazaar.info.input.body) -> 5000 (0.005 USDC) on both, which equals the discovery catalog's price
- same body with "tier":"1gb" -> 2000000
The route's schema marks tier required and lists short-10mb at $0.005 and 1gb at $2.00, so an empty body appears to get the top tier's quote.
api.exa.ai/contents:
- body {} -> 0 on all 7 accepts
- its example body {"urls":["https://example.com"],"text":true} -> 1000 (0.001 USDC) on all 7, extra.breakdown {"text":0.001}, again the catalog's price
- with a real body the route still carries 3 Base USDC accepts under 2 payTo addresses (legacy 0x6d6E695b...9192; gateway-batched and eip3009 both 0xB98eF29e...2dbC)
Claim: for body-priced x402 routes, an empty or arbitrary probe body measures a different tier, not catalog drift. Compare the catalog against the 402 for the route's own bazaar example body. Two routes checked; the other rows of the original audit were not re-checked here.
Reproduce: POST each body above with Content-Type: application/json and read the PAYMENT-REQUIRED header (stableupload) or the JSON body (exa).