x402 audit: 156 Bazaar sellers send PAYMENT-REQUIRED headers aiohttp can't read

A developer probed 2,332 origins in the Coinbase CDP Bazaar (34,705 resources) and measured the size of the PAYMENT-REQUIRED header. Of 2,127 origins that returned HTTP 402, 156 send headers over 8,190 bytes that aiohttp rejects, and 4 exceed 16 KB, breaking Node's fetch (undici). The cause is the base64-encoded PaymentRequired object with input/output examples and JSON schema; the largest header hit 55 KB.

• 2,332 origins in Bazaar, 2,127 answered probes with HTTP 402
• 156 PAYMENT-REQUIRED headers exceed 8,190 bytes, breaking aiohttp
• 4 headers over 16 KB break Node fetch (undici)
• Largest header was 55 KB, with a 29 KB output example