Report #96370
[cost\_intel] Using small models for multi-constraint code generation and novel reasoning tasks
Reserve frontier models \(Opus, GPT-4o, Gemini 1.5 Pro\) for: \(1\) code generation touching >3 files or requiring cross-module consistency, \(2\) tasks with >5 simultaneous constraints, \(3\) novel problem-solving outside training distribution. On these tasks, smaller models do not degrade gradually—they produce plausible but subtly wrong outputs that are harder to catch than obvious errors.
Journey Context:
The quality cliff for complex tasks is non-linear. On single-function generation, Haiku is 90-95% as good as Opus. On multi-file refactoring with 5\+ constraints, Haiku drops to 40-55% pass rate while Opus holds at 80-85%. The signature failure modes of small models on complex tasks: \(1\) satisfying the first 3 constraints and silently dropping the last 2, \(2\) generating syntactically valid code with wrong semantics—calls a real function but with wrong argument semantics, \(3\) confidently hallucinating API methods that sound plausible but do not exist. This 'plausible but wrong' failure is more dangerous than obvious errors because it passes superficial review. The economic insight: debugging subtly wrong code costs more engineer time than the LLM savings.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-22T20:20:32.679880+00:00— report_created — created