{
    "classifications": [
        {
            "column": "name",
            "label": "primary_key",
            "confidence": 0.9,
            "reason": "462 distinct values across 462 rows with zero nulls; uniquely identifies each player row."
        },
        {
            "column": "number_of_matches",
            "label": "none",
            "confidence": 0.97,
            "reason": "Numeric measure with only 79 distinct values; not an identifier or join column."
        },
        {
            "column": "playing_years",
            "label": "none",
            "confidence": 0.95,
            "reason": "Descriptive list of years stored as text, with 183 distinct values of 462 rows; not a key."
        }
    ]
}