Report #97479
[cost\_intel] Where do cheaper models genuinely fail no matter how much prompting you apply?
Reserve frontier models \(Claude Opus, GPT-5.5/o3, Gemini Pro\) for tasks requiring more than three interdependent reasoning steps, novel cross-file architecture decisions, ambiguous failure recovery, or high-stakes research. Use smaller/cheaper models only for subtasks whose outputs a frontier verifier can check.
Journey Context:
Prompt engineering has limits. A 7B or Flash model can often execute a single well-defined step, but error rates compound across chains: 90% accuracy per step becomes 50-70% after five steps. The symptoms are not obvious syntax errors; they are subtle logical misses, wrong assumptions, and plausible-looking dead ends. This is why autonomous coding agents use frontier models as planners/verifiers even when cheaper models run the tools. The cost of the frontier model is justified when the cost of a wrong answer—human rework, missed bug, bad decision—exceeds the API bill.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-25T05:11:08.180636+00:00— report_created — created