diff --git a/policy_evaluation/src/policy_evaluation/core.py b/policy_evaluation/src/policy_evaluation/core.py
new file mode 100644
index 0000000..2d1e1f4
--- /dev/null
+++ b/policy_evaluation/src/policy_evaluation/core.py
@@ -0,0 +1,116 @@
+from __future__ import annotations
+import json
+import argparse
+import logging
+from pathlib import Path
+from dataclasses import dataclass, asdict
+from typing import List, Dict, Any
+import numpy as np
+import pandas as pd
+
+logging.basicConfig(level=logging.INFO, format='[%(levelname)s] %(message)s')
+logger = logging.getLogger(__name__)
+
+
+@dataclass
+class LogEntry:
+    t_publish: float
+    t_gate_read: float
+    t_index_visible: float
+    pinned_flag: bool
+    timeouts: int
+    drift_signature: str
+
+    @classmethod
+    def validate(cls, entry: Dict[str, Any]) -> 'LogEntry':
+        required = {
+            't_publish': float,
+            't_gate_read': float,
+            't_index_visible': float,
+            'pinned_flag': bool,
+            'timeouts': int,
+            'drift_signature': str,
+        }
+        for k, typ in required.items():
+            if k not in entry:
+                raise ValueError(f"Missing field '{k}' in log entry")
+            if not isinstance(entry[k], typ):
+                # allow np types for numeric
+                if typ in (float, int) and isinstance(entry[k], (np.floating, np.integer)):
+                    continue
+                raise TypeError(f"Field '{k}' must be of type {typ.__name__}, got {type(entry[k]).__name__}")
+        return cls(**{k: entry[k] for k in required})
+
+
+@dataclass
+class PolicyResults:
+    p99_coverage: float
+    remaining_missing_cases: int
+    conversion_rates: float
+    max_wait_time: float
+
+    def to_json(self) -> Dict[str, Any]:
+        return asdict(self)
+
+
+def evaluate_policies(log_data: List[Dict[str, Any]]) -> PolicyResults:
+    if not isinstance(log_data, list):
+        raise TypeError("log_data must be a list of dictionaries")
+    validated_entries = [LogEntry.validate(entry) for entry in log_data]
+    if not validated_entries:
+        return PolicyResults(0.0, 0, 0.0, 0.0)
+
+    df = pd.DataFrame([asdict(e) for e in validated_entries])
+    df['wait_time'] = df['t_index_visible'] - df['t_publish']
+
+    try:
+        p99 = np.percentile(df['wait_time'], 99)
+    except IndexError:
+        p99 = 0.0
+
+    missing_cases = int((df['drift_signature'] != 'OK').sum())
+
+    # Conversion: approximate via success ratio (no timeouts)
+    conversions = len(df[df['timeouts'] == 0]) / max(len(df), 1)
+
+    max_wait = float(df['wait_time'].max()) if not df.empty else 0.0
+
+    result = PolicyResults(
+        p99_coverage=float(p99),
+        remaining_missing_cases=missing_cases,
+        conversion_rates=float(conversions),
+        max_wait_time=max_wait,
+    )
+    logger.info("Policy evaluation complete: %s", result)
+    return result
+
+
+def _load_jsonl(path: Path) -> List[Dict[str, Any]]:
+    with path.open('r', encoding='utf-8') as f:
+        return [json.loads(line.strip()) for line in f if line.strip()]
+
+
+def main():
+    parser = argparse.ArgumentParser(description="Evaluate storage policies from log data.")
+    parser.add_argument('--input', required=True, help='Pfad zur JSONL-Logdatei mit Messdaten')
+    parser.add_argument('--output', required=True, help='Pfad zur Ausgabedatei mit Evaluierungsergebnissen')
+    args = parser.parse_args()
+
+    input_path = Path(args.input)
+    output_path = Path(args.output)
+
+    if not input_path.exists():
+        raise FileNotFoundError(f"Input file not found: {input_path}")
+
+    log_data = _load_jsonl(input_path)
+    result = evaluate_policies(log_data)
+
+    output_path.parent.mkdir(parents=True, exist_ok=True)
+    with output_path.open('w', encoding='utf-8') as f:
+        json.dump(result.to_json(), f, indent=2)
+
+    logger.info("Results written to %s", output_path)
+
+
+if __name__ == '__main__':
+    main()
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