# The gateway over HTTP (real beans, real models, fake vendors)

1. normal call            -> 200 {"content":"30 days.","provider":"openai","model":"gpt-6.1-sol","promptTokens":47,"completionTokens":52,"costMicros":614,"modelCalls":1,"servedFromCache":false,"trail":["openai: ok"]}
2. openai returns 503     -> 200 {"content":"30 days.","provider":"anthropic","model":"claude-sonnet-5-5","promptTokens":47,"completionTokens":52,"costMicros":614,"modelCalls":1,"servedFromCache":false,"trail":["openai: failed with status 503","anthropic: ok"]}
3. both providers down    -> 503 Retry-After=30 No provider could answer: [openai: failed with status 503, anthropic: failed with status 529]
4. unknown hint           -> 400 Unknown model hint 'locla'. Known hints: [fast, smart]
5. tool not allow-listed  -> 400 Tool 'drop_tables' is not on the gateway allow-list [refund_order]
6. tenant over its cap    -> 429 Budget for poor would be exceeded: spent 0 of 1000 microdollars, this call may cost up to 2574
7. body claims tenant acme, header says poor -> 429 (the header wins)
8. no X-Tenant-Id header  -> 400