{"record":{"id":"c77146d10b98bce6","repo":"microsoft/autogen","slug":"unsupported-or-missing-item-type-item-type-name","errorCode":null,"errorMessage":"Unsupported or missing item type `{item_type_name}` for array field `{key}` in `{model_name}`","messagePattern":"Unsupported or missing item type `(.+?)` for array field `(.+?)` in `(.+?)`","errorType":"exception","errorClass":"UnsupportedKeywordError","httpStatus":null,"severity":"error","filePath":"python/packages/autogen-core/src/autogen_core/utils/_json_to_pydantic.py","lineNumber":277,"sourceCode":"        elif json_type == \"array\":\n            if \"minItems\" in value:\n                constraints[\"min_length\"] = value[\"minItems\"]\n            if \"maxItems\" in value:\n                constraints[\"max_length\"] = value[\"maxItems\"]\n            item_schema = value.get(\"items\", {\"type\": \"string\"})\n            if \"$ref\" in item_schema:\n                item_type = self.get_ref(item_schema[\"$ref\"].split(\"/\")[-1])\n            elif item_schema.get(\"type\") == \"object\" and \"properties\" in item_schema:\n                # Handle array items that are objects with properties - create a nested model\n                # Use hash-based naming to keep names short and unique\n                item_model_name = self._get_item_model_name(key, model_name)\n                item_type = self._json_schema_to_model(item_schema, item_model_name, root_schema)\n            else:\n                item_type_name = item_schema.get(\"type\")\n                if item_type_name is None:\n                    item_type = str\n                elif item_type_name not in TYPE_MAPPING:\n                    raise UnsupportedKeywordError(\n                        f\"Unsupported or missing item type `{item_type_name}` for array field `{key}` in `{model_name}`\"\n                    )\n                else:\n                    item_type = TYPE_MAPPING[item_type_name]\n\n            base_type = conlist(item_type, **constraints) if constraints else List[item_type]  # type: ignore[valid-type]\n\n        if \"format\" in value:\n            format_type = FORMAT_MAPPING.get(value[\"format\"])\n            if format_type is None:\n                raise FormatNotSupportedError(f\"Unknown format `{value['format']}` for `{key}` in `{model_name}`\")\n            if not isinstance(format_type, type):\n                return format_type\n            if not issubclass(format_type, str):\n                return format_type\n            return format_type\n\n        return base_type","sourceCodeStart":259,"sourceCodeEnd":295,"githubUrl":"https://github.com/microsoft/autogen/blob/027ecf0a379bcc1d09956d46d12d44a3ad9cee14/python/packages/autogen-core/src/autogen_core/utils/_json_to_pydantic.py#L259-L295","documentation":"Error \"Unsupported or missing item type `{item_type_name}` for array field `{key}` in `{model_name}`\" thrown in microsoft/autogen.","triggerScenarios":"Thrown at python/packages/autogen-core/src/autogen_core/utils/_json_to_pydantic.py:277 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":["Define a supported items type"],"exampleFix":"Set 'items': {'type': 'string'} (or other supported type)","handlingStrategy":null,"validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"027ecf0a379bcc1d09956d46d12d44a3ad9cee14","analyzedAt":"2026-08-15T03:38:00.719Z","schemaVersion":2},"datasetVersion":"2026-08-15T17:31:12.345Z"}