{"record":{"id":"a063f7f3aa54d598","repo":"rohitg00/ai-engineering-from-scratch","slug":"uncertainfallback-is-required","errorCode":null,"errorMessage":"uncertainFallback is required","messagePattern":"uncertainFallback is required","errorType":"validation","errorClass":"ValueError","httpStatus":null,"severity":"error","filePath":"certifications/claude/lessons/02-model-selection-and-token-economics/code/main.py","lineNumber":63,"sourceCode":"        if not str(case.get(\"routingSignal\", \"\")).strip():\n            errors.append(f\"cases[{index}] needs an observable routingSignal\")\n        if case.get(\"riskClass\") == \"consequential\" and case.get(\"humanReview\") is not True:\n            errors.append(f\"cases[{index}] consequential work must have humanReview\")\n    comparison = benchmark.get(\"routingComparison\")\n    routed = sum(case.get(\"estimatedCostUnits\", 0) for case in cases if isinstance(case, dict))\n    if not isinstance(comparison, dict) or comparison.get(\"routedCostUnits\") != routed:\n        errors.append(\"routedCostUnits must equal the case total\")\n    elif comparison.get(\"allCapableCostUnits\", 0) <= routed:\n        errors.append(\"allCapableCostUnits must exceed routedCostUnits\")\n    if not isinstance(comparison, dict) or not str(comparison.get(\"uncertainFallback\", \"\")).strip():\n        errors.append(\"uncertainFallback is required\")\n    return errors\n\n\ndef summarize(benchmark: dict[str, Any]) -> dict[str, Any]:\n    errors = validate_benchmark(benchmark)\n    if errors:\n        raise ValueError(\"; \".join(errors))\n    lanes = Counter(case[\"chosenModel\"] for case in benchmark[\"cases\"])\n    comparison = benchmark[\"routingComparison\"]\n    return {\n        \"caseCount\": len(benchmark[\"cases\"]),\n        \"lanes\": dict(sorted(lanes.items())),\n        \"costSavedUnits\": comparison[\"allCapableCostUnits\"] - comparison[\"routedCostUnits\"],\n        \"humanReviewCases\": sum(case[\"humanReview\"] for case in benchmark[\"cases\"]),\n    }\n\n\ndef validate_mode_trials(experiment: dict[str, Any]) -> list[str]:\n    errors: list[str] = []\n    if experiment.get(\"measurementStatus\") != \"illustrative-not-live-provider-runs\":\n        errors.append(\"mode trials must identify illustrative measurements\")\n    if not str(experiment.get(\"settingSemantics\", \"\")).strip():\n        errors.append(\"mode trials must explain normalized setting labels\")\n    verified_on = experiment.get(\"verifiedOn\")\n    if not _iso_date(verified_on):","sourceCodeStart":45,"sourceCodeEnd":81,"githubUrl":"https://github.com/rohitg00/ai-engineering-from-scratch/blob/39ea8a1c6d0b61f071226eff7ede4d4105fed820/certifications/claude/lessons/02-model-selection-and-token-economics/code/main.py#L45-L81","documentation":"Error \"uncertainFallback is required\" thrown in rohitg00/ai-engineering-from-scratch.","triggerScenarios":"Thrown at certifications/claude/lessons/02-model-selection-and-token-economics/code/main.py:63 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":[],"exampleFix":null,"handlingStrategy":null,"validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"39ea8a1c6d0b61f071226eff7ede4d4105fed820","analyzedAt":"2026-08-26T03:13:46.626Z","schemaVersion":2},"datasetVersion":"2026-08-26T07:17:17.940Z"}