diff --git a/quality_scorer.py b/quality_scorer.py
new file mode 100644
index 0000000..6d4f1ce
--- /dev/null
+++ b/quality_scorer.py
@@ -0,0 +1,203 @@
+#!/usr/bin/env python3
+from __future__ import annotations
+
+import json
+import re
+import time
+from dataclasses import dataclass
+from typing import Any, Dict, List, Tuple
+
+DEFAULT_WEIGHTS = {
+    "completeness": 0.30,
+    "format_compliance": 0.20,
+    "coverage": 0.25,
+    "clarity": 0.15,
+    "validity": 0.10,
+}
+
+
+@dataclass
+class ScoreResult:
+    weighted_score: float
+    quality_rating: str
+    scores: Dict[str, float]
+    feedback: List[str]
+    pass_threshold: bool
+
+    def to_dict(self) -> Dict[str, Any]:
+        return {
+            "weighted_score": round(self.weighted_score, 4),
+            "quality_rating": self.quality_rating,
+            "scores": {k: round(v, 4) for k, v in self.scores.items()},
+            "feedback": self.feedback,
+            "pass_threshold": self.pass_threshold,
+        }
+
+
+def _clamp(x: float) -> float:
+    return max(0.0, min(1.0, x))
+
+
+def _tokenize(text: str) -> List[str]:
+    return re.findall(r"[A-Za-z0-9_]+", text.lower())
+
+
+def _detect_format(text: str) -> str:
+    t = text.strip()
+    if not t:
+        return "text"
+    if (t.startswith("{") and t.endswith("}")) or (t.startswith("[") and t.endswith("]")):
+        try:
+            json.loads(t)
+            return "json"
+        except Exception:
+            pass
+    if "```" in t or re.search(r"\b(def|class|function|const|let|var|import|return)\b", t):
+        return "code"
+    if re.search(r"(^#\s)|(^-\s)|(^\d+\.\s)", t, re.M):
+        return "markdown"
+    return "text"
+
+
+def _weights_or_default(weights: Dict[str, float] | None) -> Dict[str, float]:
+    active = dict(DEFAULT_WEIGHTS)
+    if weights:
+        active.update(weights)
+    total = sum(active.values()) or 1.0
+    # normalize to 1.0
+    return {k: v / total for k, v in active.items()}
+
+
+def _score_dimensions(submission: str, rubric_keywords: List[str]) -> Tuple[str, Dict[str, float]]:
+    fmt = _detect_format(submission)
+    txt = submission.strip()
+    tokens = _tokenize(txt)
+
+    completeness = _clamp(len(tokens) / 120.0)
+    if fmt in ("json", "markdown", "code"):
+        completeness = _clamp(completeness + 0.12)
+
+    if fmt == "json":
+        try:
+            parsed = json.loads(txt)
+            format_compliance = 0.95 if isinstance(parsed, (dict, list)) else 0.8
+        except Exception:
+            format_compliance = 0.2
+    elif fmt == "markdown":
+        format_compliance = 0.82 if re.search(r"(^#\s)|(^-\s)|(^\d+\.\s)", txt, re.M) else 0.55
+    elif fmt == "code":
+        format_compliance = 0.82 if re.search(r"[{}();]|\n\s{2,}\w", txt) else 0.58
+    else:
+        format_compliance = 0.72
+
+    hits = sum(1 for k in rubric_keywords if k.lower() in txt.lower())
+    coverage = _clamp(hits / max(1, len(rubric_keywords)))
+
+    punct = len(re.findall(r"[.!?]", txt))
+    symbol_noise = len(re.findall(r"[^\w\s\.,;:!?\-\(\)\[\]\{\}'\"/\\]", txt))
+    clarity = 0.62 + min(0.22, punct / 20.0) - min(0.30, symbol_noise / max(1, len(txt)) * 5)
+    clarity = _clamp(clarity)
+
+    validity = 0.65
+    if fmt == "json":
+        try:
+            parsed = json.loads(txt)
+            validity = 0.9 if isinstance(parsed, (dict, list)) else 0.75
+        except Exception:
+            validity = 0.12
+    elif fmt == "code":
+        brackets_ok = txt.count("(") == txt.count(")") and txt.count("{") == txt.count("}")
+        validity = 0.8 if brackets_ok else 0.45
+
+    return fmt, {
+        "completeness": round(completeness, 4),
+        "format_compliance": round(format_compliance, 4),
+        "coverage": round(coverage, 4),
+        "clarity": round(clarity, 4),
+        "validity": round(validity, 4),
+    }
+
+
+def _rating(weighted: float) -> str:
+    if weighted >= 0.85:
+        return "excellent"
+    if weighted >= 0.7:
+        return "good"
+    if weighted >= 0.5:
+        return "fair"
+    return "poor"
+
+
+def _feedback(scores: Dict[str, float]) -> List[str]:
+    fb = []
+    messages = {
+        "completeness": "内容不够完整，建议补充上下文、步骤和结果。",
+        "format_compliance": "格式规范不足，建议按目标格式（JSON/Markdown/Code）整理。",
+        "coverage": "覆盖面偏低，建议补全 rubric 关键词相关内容。",
+        "clarity": "表达清晰度一般，建议拆句并减少噪声字符。",
+        "validity": "有效性偏弱，建议修复结构错误或语法问题。",
+    }
+    for k, v in scores.items():
+        if v < 0.5:
+            fb.append(messages[k])
+    if not fb:
+        fb.append("整体质量较好，已覆盖主要评分维度。")
+    return fb
+
+
+def score_submission(
+    submission: str,
+    rubric_keywords: List[str] | None = None,
+    threshold: float = 0.7,
+    weights: Dict[str, float] | None = None,
+) -> Dict[str, Any]:
+    rubric_keywords = rubric_keywords or ["summary", "steps", "result"]
+    active_weights = _weights_or_default(weights)
+
+    _, scores = _score_dimensions(submission, rubric_keywords)
+    weighted = sum(scores[k] * active_weights[k] for k in active_weights)
+
+    return ScoreResult(
+        weighted_score=weighted,
+        quality_rating=_rating(weighted),
+        scores=scores,
+        feedback=_feedback(scores),
+        pass_threshold=weighted >= threshold,
+    ).to_dict()
+
+
+def evaluate_against_ground_truth(dataset: List[Dict[str, Any]]) -> Dict[str, Any]:
+    """dataset item: {submission:str, expected_score:float, rubric_keywords?:list[str]}"""
+    abs_errors: List[float] = []
+    results = []
+    for item in dataset:
+        out = score_submission(item["submission"], item.get("rubric_keywords"))
+        err = abs(out["weighted_score"] - float(item["expected_score"]))
+        abs_errors.append(err)
+        results.append(
+            {
+                "expected": round(float(item["expected_score"]), 4),
+                "predicted": out["weighted_score"],
+                "abs_error": round(err, 4),
+                "quality_rating": out["quality_rating"],
+            }
+        )
+
+    mae = sum(abs_errors) / max(1, len(abs_errors))
+    max_error = max(abs_errors) if abs_errors else 0.0
+    within_point_05 = sum(1 for e in abs_errors if e <= 0.05) / max(1, len(abs_errors))
+
+    return {
+        "count": len(dataset),
+        "mae": round(mae, 4),
+        "max_error": round(max_error, 4),
+        "within_point_05_ratio": round(within_point_05, 4),
+        "results": results,
+    }
+
+
+def benchmark_100(submissions: List[str]) -> float:
+    start = time.time()
+    for s in submissions[:100]:
+        score_submission(s)
+    return time.time() - start
diff --git a/test_quality_scorer.py b/test_quality_scorer.py
new file mode 100644
index 0000000..695627b
--- /dev/null
+++ b/test_quality_scorer.py
@@ -0,0 +1,71 @@
+#!/usr/bin/env python3
+import json
+import unittest
+
+from quality_scorer import benchmark_100, evaluate_against_ground_truth, score_submission
+
+
+class TestQualityScorer(unittest.TestCase):
+    def test_output_schema(self):
+        out = score_submission('{"summary":"ok","steps":[1,2],"result":"done"}')
+        self.assertIn("weighted_score", out)
+        self.assertIn("quality_rating", out)
+        self.assertIn("scores", out)
+        self.assertIn("feedback", out)
+        self.assertIn("pass_threshold", out)
+        self.assertEqual(
+            set(out["scores"].keys()),
+            {"completeness", "format_compliance", "coverage", "clarity", "validity"},
+        )
+
+    def test_formats(self):
+        samples = [
+            '{"summary":"hello","result":"x"}',
+            '# Title\n- step 1\n- step 2\nresult done',
+            'def run(x):\n    return x+1',
+            'plain text summary steps and result',
+        ]
+        for s in samples:
+            out = score_submission(s)
+            self.assertGreaterEqual(out["weighted_score"], 0.0)
+            self.assertLessEqual(out["weighted_score"], 1.0)
+
+    def test_benchmark(self):
+        subs = [json.dumps({"summary": "a", "steps": [1, 2, 3], "result": "ok"}) for _ in range(100)]
+        sec = benchmark_100(subs)
+        self.assertLess(sec, 10.0)
+
+    def test_ground_truth_alignment(self):
+        # 20 samples with expected scores that this heuristic should approximate.
+        dataset = [
+            {"submission": '{"summary":"clear summary","steps":["a","b"],"result":"done"}', "expected_score": 0.84},
+            {"submission": '{"summary":"short","result":"ok"}', "expected_score": 0.68},
+            {"submission": '# Report\n- summary\n- steps\n- result', "expected_score": 0.78},
+            {"submission": 'summary: yes. steps: yes. result: yes.', "expected_score": 0.72},
+            {"submission": 'def run(x):\n    # summary\n    return x', "expected_score": 0.66},
+            {"submission": '{"foo":1}', "expected_score": 0.53},
+            {"submission": 'random words only', "expected_score": 0.38},
+            {"submission": '```python\ndef x():\n    return 1\n```', "expected_score": 0.58},
+            {"submission": '1. summary\n2. steps\n3. result', "expected_score": 0.76},
+            {"submission": '{"summary":"ok","steps":[1,2,3],"result":"final"}', "expected_score": 0.86},
+            {"submission": '{"summary":"ok","steps":[],"result":"done"}', "expected_score": 0.77},
+            {"submission": '### Header\nresult only', "expected_score": 0.54},
+            {"submission": 'summary and steps but no final result', "expected_score": 0.61},
+            {"submission": '{"summary":"detailed","steps":["a","b","c"],"result":"good","notes":"clear"}', "expected_score": 0.88},
+            {"submission": 'def bad(x:\n    return x', "expected_score": 0.44},
+            {"submission": '# title\n- summary\ntext text text\nresult', "expected_score": 0.67},
+            {"submission": '{"summary":"s","steps":["1"],"result":"r","extra":"..."}', "expected_score": 0.79},
+            {"submission": 'plain text with summary steps result and clear ending.', "expected_score": 0.74},
+            {"submission": '{"summary":"none"}', "expected_score": 0.56},
+            {"submission": 'tiny', "expected_score": 0.3},
+        ]
+        metrics = evaluate_against_ground_truth(dataset)
+        self.assertEqual(metrics["count"], 20)
+        # Heuristic baseline keeps average error reasonably small; this can be tightened
+        # if/when a trained calibrator is introduced.
+        self.assertLessEqual(metrics["mae"], 0.15)
+        self.assertGreaterEqual(metrics["within_point_05_ratio"], 0.10)
+
+
+if __name__ == "__main__":
+    unittest.main()