diff --git a/scripts/domain/attribute_formula.gd b/scripts/domain/attribute_formula.gd
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index 0000000..345917a
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+++ b/scripts/domain/attribute_formula.gd
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+## AttributeFormula — 属性合成公式的唯一实现处
+## 纯静态函数：无状态、不依赖 PlayerStats / EventBus / 场景树，故可脱离游戏进程单元测试
+## 权威来源：docs_dev/specs/2026-07-31-player-attributes-design.md §2.1 / §2.3
+class_name AttributeFormula
+extends RefCounted
+
+enum Combine { HYBRID, INVERSE, ADD_INT }
+
+const _COMBINE_NAMES: Dictionary = {
+	"hybrid":  Combine.HYBRID,
+	"inverse": Combine.INVERSE,
+	"add_int": Combine.ADD_INT,
+}
+
+## JSON 的 combine 字符串 → 枚举；未知值 push_error 并回退 HYBRID
+static func combine_from_string(s: String) -> Combine:
+	if _COMBINE_NAMES.has(s):
+		return _COMBINE_NAMES[s]
+	push_error("AttributeFormula: 未知 combine「%s」，回退 hybrid" % s)
+	return Combine.HYBRID
+
+## 唯一的公式入口
+## base     —— attributes.json 的基准值
+## mods     —— [{"mode": "flat"|"pct", "value": float}, ...]；调用方负责只传本属性的加成
+## attr_def —— attributes.json 中该属性的定义（读 combine / hard）
+## 返回统一为 float；add_int 属性由调用方做 int() 转换（公式模块不感知目标字段类型）
+static func compute(base: float, mods: Array, attr_def: Dictionary) -> float:
+	var combine: Combine = combine_from_string(String(attr_def.get("combine", "hybrid")))
+	var hard: float = float(attr_def.get("hard", 0.0))
+	var flat_sum: float = 0.0
+	var pct_prod: float = 1.0
+	for m in mods:
+		var mode: String = String(m.get("mode", "flat"))
+		var v: float = float(m.get("value", 0.0))
+		if mode == "flat":
+			flat_sum += v
+		elif mode == "pct":
+			if combine == Combine.ADD_INT:
+				push_error("AttributeFormula: add_int 属性不接受 pct 加成（value=%f），已忽略" % v)
+				continue
+			# 连乘而非线性求和：三条 +20% = ×1.728 而非 ×1.6，避免后期线性失控
+			pct_prod *= (1.0 + v) if combine == Combine.HYBRID else (1.0 - v)
+		else:
+			push_error("AttributeFormula: 未知 mode「%s」，已忽略" % mode)
+	match combine:
+		Combine.ADD_INT:
+			var ri: float = floorf(base + flat_sum)
+			return clampf(ri, 0.0, hard) if hard > 0.0 else maxf(0.0, ri)
+		Combine.INVERSE:
+			# 越低越快：hard 是**下限**
+			return maxf(hard, (base + flat_sum) * pct_prod)
+		_:
+			var r: float = maxf(0.0, (base + flat_sum) * pct_prod)
+			return minf(r, hard) if hard > 0.0 else r   # hard=0.0 约定为「不钳制」
diff --git a/scripts/domain/attribute_formula.gd.uid b/scripts/domain/attribute_formula.gd.uid
new file mode 100644
index 0000000..453e7a0
--- /dev/null
+++ b/scripts/domain/attribute_formula.gd.uid
@@ -0,0 +1 @@
+uid://c41seas4fosx2