A daily improvement cycle analyzes 500 traces, generates 3 candidate prompts, and evaluates each against a 50-example test set. At GPT-4o rates, what is the approximate cost per cycle?
- About $50-100, because each candidate must be evaluated against the full 500-trace dataset to ensure statistical significance across the complete distribution of production queries
- About $500-1000, because shadow evaluation runs both the current and candidate prompts on all production traffic during the cycle to collect paired quality comparisons
- About $0.10-0.30, because the meta-agent reuses cached LLM responses from the production agent's earlier calls and only pays for the incremental tokens in the analysis prompt
- About $3-8, computed as trace analysis ($0.20-0.50) plus 3 candidates at $0.30-0.50 generation each plus 3 evaluations at $0.50-1.00 each on the 50-example test set
Why
The improvement cycle has three cost components. Trace analysis reads 100 failure traces and uses an LLM to categorize them by root cause, costing approximately $0.20-0.50 in API calls. Candidate generation produces 3 prompt revisions, each requiring one LLM call to analyze the failure patterns and propose changes, costing approximately $0.30-0.50 per candidate. Evaluation runs each candidate against a 50-example test set, making 50 LLM calls per candidate at the production model's rate, costing approximately $0.50-1.00 per candidate. Total: $0.20-0.50 plus 3 times $0.30-0.50 plus 3 times $0.50-1.00 equals approximately $3-8 per cycle. The $50-100 estimate incorrectly assumes evaluation against the full 500-trace dataset rather than the held-out 50-example test set. The $0.10-0.30 estimate incorrectly claims cached responses are reused. The $500-1000 estimate incorrectly includes shadow evaluation, which is a separate testing strategy not part of every improvement cycle. For a system spending $500 per day on production LLM calls, $3-8 adds only 0.6-1.6% overhead.