Day 73: Draft-Then-Verify Routing

Not every token deserves the expensive model. Draft-then-verify routes cheap drafts to an expensive gate for risky or low-confidence outputs — saving money without shipping unchecked diffs.

⚡ TL;DR: Cheap model drafts intents/plans; verifier model (or tests+critic) gates apply. Route by risk score and confidence. Tests still run regardless of model route.

Router

RISKY_PATHS = ("/terraform/", "/iam/", "/payments/")

def needs_expensive_gate(intent: dict, conf: float) -> bool:
    if any(p in intent["path"] for p in RISKY_PATHS):
        return True
    return conf < 0.7

export async function draftThenVerify(goal: string) {
  const draft = await cheap.complete(goal);
  if (!needsExpensiveGate(draft)) return draft;
  const verdict = await expensive.verify(draft);
  if (!verdict.ok) throw new Error("verify_reject");
  return draft;
}

✅ Tests still run regardless of model route — verify ≠ skip CI.

Closing checklist

• [ ] Risk-based routing
• [ ] Expensive verify on risky paths
• [ ] Keep deterministic tests as ground truth
• [ ] Log which model drafted vs verified
• [ ] Eval both paths in the suite

Series navigation

Day 72: Prompt Caching Pitfalls · Day 74: Batch Inference Overnight

Last updated September 11, 2026