{"record":{"id":"675ece0355443a0b","repo":"rohitg00/ai-engineering-from-scratch","slug":"unexpected-fields-join-sorted-unexpected","errorCode":null,"errorMessage":"unexpected fields: {', '.join(sorted(unexpected))}","messagePattern":"unexpected fields: (.+?)","errorType":"validation","errorClass":"ValueError","httpStatus":null,"severity":"error","filePath":"certifications/claude/lessons/10-tool-use-and-agentic-loops/code/main.py","lineNumber":174,"sourceCode":"        if maximum is not None and len(value) > maximum:\n            raise ValueError(f\"invalid item count for {location}: above maxItems {maximum}\")\n        if \"items\" in schema:\n            for index, item in enumerate(value):\n                _validate_schema_value(item, schema[\"items\"], f\"{location}[{index}]\")\n\n    if isinstance(value, dict):\n        properties = schema.get(\"properties\", {})\n        if not isinstance(properties, dict):\n            raise ValueError(f\"schema properties for {location} must be an object\")\n        required = schema.get(\"required\", [])\n        if not isinstance(required, list) or not all(isinstance(name, str) for name in required):\n            raise ValueError(f\"schema required for {location} must be a string list\")\n        missing = [name for name in required if name not in value]\n        if missing:\n            raise ValueError(f\"missing required fields: {', '.join(missing)}\")\n        unexpected = set(value) - set(properties)\n        if unexpected and schema.get(\"additionalProperties\") is False:\n            raise ValueError(f\"unexpected fields: {', '.join(sorted(unexpected))}\")\n        for name, item in value.items():\n            if name in properties:\n                _validate_schema_value(item, properties[name], f\"{location}.{name}\")\n\n\n@dataclass(frozen=True)\nclass Tool:\n    name: str\n    description: str\n    input_schema: dict[str, Any]\n    handler: Callable[[dict[str, Any]], Any]\n    mutates: bool = False\n\n    def validate(self, arguments: dict[str, Any]) -> None:\n        if not isinstance(arguments, dict):\n            raise ValueError(\"tool input must be an object\")\n        _validate_schema_value(arguments, self.input_schema, \"tool input\")\n","sourceCodeStart":156,"sourceCodeEnd":192,"githubUrl":"https://github.com/rohitg00/ai-engineering-from-scratch/blob/39ea8a1c6d0b61f071226eff7ede4d4105fed820/certifications/claude/lessons/10-tool-use-and-agentic-loops/code/main.py#L156-L192","documentation":"Error \"unexpected fields: {', '.join(sorted(unexpected))}\" thrown in rohitg00/ai-engineering-from-scratch.","triggerScenarios":"Thrown at certifications/claude/lessons/10-tool-use-and-agentic-loops/code/main.py:174 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"}