TL;DR: I audited a friend's startup that was spending $4,200/month on Claude API. Only $1,300 produced business value. The other $2,900 was waste — split across three patterns that hit most teams using LLM APIs in production. Here's how to find them in your own bill, and the code to fix each one.
The audit
A friend running a B2B doc-summarization product asked me to look at their Claude bill. Q1 was $4,200/month and climbing. We pulled their request logs into a spreadsheet, classified each call by purpose, then estimated what each should have cost. The answer was uncomfortable:
Bucket
Cost
