Model prices are easy to compare. The cost of a useful result takes a little more work.
Before connecting a model to an agent workflow, I suggest writing an acceptance test for a small, representative set of tasks. For a text task, that may mean checking the requested structure and source support. For an image or video task, it may mean checking dimensions, duration and whether the result actually meets the brief.
Record four things for each provider run:
- The exact model and output specification.
- Every charged attempt, including retries.
- Whether the output passed the same acceptance criteria.
- The time until an accepted result was available.
A simple calculation is cost per accepted result = total charged cost / accepted outputs. For example, a hypothetical run costing $2 with 40 accepted outputs has a cost of $0.05 per accepted output. That is an example calculation, not a provider price quote.
Keep failure cases in the report. A provider that works well for one task may fail on another, and changing models halfway through a comparison makes the conclusions harder to use.
Disclosure: I work on BeatAPI, the professional capability layer for any agent, described as OpenRouter for Agents. Its current capabilities include text, image and video models, Social Data, SEO Data and Web Search. The checklist above is how I would approach evaluating an API for a particular workload: verify the same model and specification, then measure accepted results before scaling.
What acceptance check has caught the most expensive failure in your own agent workflow?
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