The Real Cost of Your AI Agent (It's Not What You Think)

Your OpenAI invoice shows token counts. What it doesn't show is how many of those tokens produced nothing useful. Failed calls, retries, model over-provisioning, and calls that returned an answer nobody used - these are where agent costs actually go, and none of them appear in standard billing dashboards. Cost Per Call vs Cost Per Successful Outcome The metric that matters isn't cost per call. It's cost per successful outcome. If your agent costs $0.008 per call but succeeds 60% of the time, your real cost per successful outcome is $0.013. If a different configuration costs $0.012 per call but succeeds 90% of the time, the real cost is $0.013. They're equivalent on a per-outcome basis, but only one of those configurations surfaces as "expensive" in a naive cost analysis. This is the measurement problem: optimizing for cost per call without tracking success rate will push you toward cheaper models that fail more, which can increase cost per successful outcome while appearing to save mon