{
    "classifications": [
        {
            "column": "Name",
            "label": "none",
            "confidence": 0.6,
            "reason": "Player name with 462 distinct values across 237k rows; repeats heavily, an entity attribute rather than a verified join key"
        },
        {
            "column": "Date",
            "label": "none",
            "confidence": 0.85,
            "reason": "Date text with repeated values; not a key"
        },
        {
            "column": "Tournament",
            "label": "none",
            "confidence": 0.7,
            "reason": "Tournament name, descriptive attribute with repeats"
        },
        {
            "column": "Surface",
            "label": "none",
            "confidence": 0.95,
            "reason": "Low-cardinality category"
        },
        {
            "column": "Rd",
            "label": "none",
            "confidence": 0.95,
            "reason": "Round code, low-cardinality category"
        },
        {
            "column": "Rk",
            "label": "none",
            "confidence": 0.9,
            "reason": "Player ranking measure, not a key"
        },
        {
            "column": "vRk",
            "label": "none",
            "confidence": 0.9,
            "reason": "Opponent ranking measure, not a key"
        },
        {
            "column": "against",
            "label": "none",
            "confidence": 0.75,
            "reason": "Messy opponent text at 97.7% distinct, below the 98% near_key threshold"
        },
        {
            "column": "Score",
            "label": "none",
            "confidence": 0.95,
            "reason": "Match score text with repeats"
        },
        {
            "column": "TP",
            "label": "none",
            "confidence": 0.95,
            "reason": "Numeric stat with nulls"
        },
        {
            "column": "Aces",
            "label": "none",
            "confidence": 0.95,
            "reason": "Numeric stat"
        },
        {
            "column": "DFs",
            "label": "none",
            "confidence": 0.95,
            "reason": "Numeric stat"
        },
        {
            "column": "SP",
            "label": "none",
            "confidence": 0.95,
            "reason": "Numeric stat"
        },
        {
            "column": "1SP",
            "label": "none",
            "confidence": 0.95,
            "reason": "Numeric stat"
        },
        {
            "column": "2SP",
            "label": "none",
            "confidence": 0.95,
            "reason": "Numeric stat"
        },
        {
            "column": "vA",
            "label": "none",
            "confidence": 0.95,
            "reason": "Numeric stat"
        },
        {
            "column": "Time",
            "label": "none",
            "confidence": 0.95,
            "reason": "Match duration text, repeated values"
        }
    ]
}