1) Real-World Starting Scenario​

Friday night. End of month. One founder, one billing page, one number that does not make sense.

Two months earlier, their AI product looked efficient:

• inference API was cheap
• retrieval worked in demos
• team velocity was high

Then usage jumped.

Not because of marketing. Because one customer shared a workflow internally and the product got real traffic before the team had real operational controls.

Prompt sizes crept up. Retrieval depth increased "just for quality." Retry settings got more aggressive after a latency incident. Logs were switched to full payload mode for debugging. Another model provider got added as fallback.

None of these decisions looked reckless in isolation.

Together, they formed a cost amplifier.