diff --git a/packages/core/src/__tests__/api.test.ts b/packages/core/src/__tests__/api.test.ts
index 6905960..5591e88 100644
--- a/packages/core/src/__tests__/api.test.ts
+++ b/packages/core/src/__tests__/api.test.ts
@@ -34,6 +34,23 @@ describe("api", () => {
     });
   });
 
+  describe("evaluate and evaluateAll consistency", () => {
+    it("both return false for an invalid status value", () => {
+      const flagsConfig = [
+        {
+          key: "new-homepage",
+          status: "enbaled" as FlagsConfiguration[number]["status"],
+          strategies: [],
+        },
+      ];
+
+      const engine = createFlagEngine(flagsConfig);
+      const userCtx = engine.createUserContext({ __id: "yo" });
+      expect(userCtx.evaluate("new-homepage")).toEqual(false);
+      expect(userCtx.evaluateAll()).toEqual({ "new-homepage": false });
+    });
+  });
+
   describe("evaluate", () => {
     it("returns false when the flag does not exist", () => {
       const flagsConfig: FlagsConfiguration = [
diff --git a/packages/core/src/__tests__/isEligibleForStrategy.test.ts b/packages/core/src/__tests__/isEligibleForStrategy.test.ts
index a3d7f47..9c7c061 100644
--- a/packages/core/src/__tests__/isEligibleForStrategy.test.ts
+++ b/packages/core/src/__tests__/isEligibleForStrategy.test.ts
@@ -294,6 +294,72 @@ describe("isEligibleForStrategy", () => {
     }
   );
 
+  it("not_contains returns true when the field is missing from user configuration", () => {
+    const rules: Rule[] = [
+      {
+        operator: "not_contains",
+        field: "email",
+        value: "@competitor.com",
+      },
+    ];
+
+    const userConfiguration: UserConfiguration = {
+      __id: "yo",
+    };
+
+    expect(isEligibleForStrategy(rules, userConfiguration)).toBe(true);
+  });
+
+  it("not_contains returns true when the field is a non-string value", () => {
+    const rules: Rule[] = [
+      {
+        operator: "not_contains",
+        field: "email",
+        value: "@competitor.com",
+      },
+    ];
+
+    const userConfiguration: UserConfiguration = {
+      __id: "yo",
+      email: 42,
+    };
+
+    expect(isEligibleForStrategy(rules, userConfiguration)).toBe(true);
+  });
+
+  it("not_contains returns false when the rule value is not a string", () => {
+    const rules: Rule[] = [
+      {
+        operator: "not_contains",
+        field: "email",
+        value: 123,
+      },
+    ];
+
+    const userConfiguration: UserConfiguration = {
+      __id: "yo",
+      email: "test@example.com",
+    };
+
+    expect(isEligibleForStrategy(rules, userConfiguration)).toBe(false);
+  });
+
+  it("not_in returns true when the field is missing from user configuration", () => {
+    const rules: Rule[] = [
+      {
+        operator: "not_in",
+        field: "country",
+        value: ["US", "UK"],
+      },
+    ];
+
+    const userConfiguration: UserConfiguration = {
+      __id: "yo",
+    };
+
+    expect(isEligibleForStrategy(rules, userConfiguration)).toBe(true);
+  });
+
   it.each([
     [2, [1, 2, 3], false],
     [4, [1, 2, 3], true],
@@ -330,4 +396,58 @@ describe("isEligibleForStrategy", () => {
       expect(isEligibleForStrategy(rules, userConfiguration)).toBe(expected);
     }
   );
+
+  describe("segment depth protection", () => {
+    const buildNestedSegment = (depth: number): Rule => {
+      let innermost: Rule = {
+        field: "country",
+        operator: "equals",
+        value: "FR",
+      };
+
+      for (let i = 0; i < depth; i++) {
+        innermost = {
+          inSegment: {
+            name: `segment-${i}`,
+            rules: [innermost],
+          },
+        };
+      }
+
+      return innermost;
+    };
+
+    it("returns false when segment nesting exceeds MAX_SEGMENT_DEPTH (10)", () => {
+      const deepRule = buildNestedSegment(11);
+
+      const userConfiguration: UserConfiguration = {
+        __id: "yo",
+        country: "FR",
+      };
+
+      expect(isEligibleForStrategy([deepRule], userConfiguration)).toBe(false);
+    });
+
+    it("returns true when segment nesting is exactly at MAX_SEGMENT_DEPTH (10)", () => {
+      const deepRule = buildNestedSegment(10);
+
+      const userConfiguration: UserConfiguration = {
+        __id: "yo",
+        country: "FR",
+      };
+
+      expect(isEligibleForStrategy([deepRule], userConfiguration)).toBe(true);
+    });
+
+    it("returns false when segment nesting is at MAX_SEGMENT_DEPTH but rule doesn't match", () => {
+      const deepRule = buildNestedSegment(10);
+
+      const userConfiguration: UserConfiguration = {
+        __id: "yo",
+        country: "US",
+      };
+
+      expect(isEligibleForStrategy([deepRule], userConfiguration)).toBe(false);
+    });
+  });
 });
diff --git a/packages/core/src/__tests__/repartition.test.ts b/packages/core/src/__tests__/repartition.test.ts
index 422a9b1..4668a12 100644
--- a/packages/core/src/__tests__/repartition.test.ts
+++ b/packages/core/src/__tests__/repartition.test.ts
@@ -2,7 +2,7 @@ import { describe, expect, it } from "vitest";
 import { createFlagEngine } from "..";
 
 describe("repartition", () => {
-  it("should be distributive", () => {
+  it("should distribute 50/50 across 1M users", () => {
     const engine = createFlagEngine([
       {
         key: "summer-sale",
@@ -49,7 +49,7 @@ describe("repartition", () => {
     expect(B).toBeLessThan(halfCountUpper);
   });
 
-  it("should be distributive", () => {
+  it("should distribute 50/50 across 10M users with tighter tolerance", () => {
     const engine = createFlagEngine([
       {
         key: "summer-sale",
@@ -96,7 +96,7 @@ describe("repartition", () => {
     expect(B).toBeLessThan(halfCountUpper);
   });
 
-  it("should be distributive", () => {
+  it("should distribute 10/20/30/40 across four variants", () => {
     const engine = createFlagEngine([
       {
         key: "summer-sale",
diff --git a/packages/core/src/getEligibleStrategy.ts b/packages/core/src/getEligibleStrategy.ts
index 6421c7c..2af0a58 100644
--- a/packages/core/src/getEligibleStrategy.ts
+++ b/packages/core/src/getEligibleStrategy.ts
@@ -76,11 +76,9 @@ export const isEligibleForStrategy = (
       case "not_contains": {
         const fieldValue = userConfiguration[rule.field];
 
-        return (
-          isString(fieldValue) &&
-          isString(rule.value) &&
-          !fieldValue.includes(rule.value)
-        );
+        if (!isString(rule.value)) return false;
+        if (!isString(fieldValue)) return true;
+        return !fieldValue.includes(rule.value);
       }
 
       case "in": {
@@ -94,9 +92,8 @@ export const isEligibleForStrategy = (
       case "not_in": {
         const fieldValue = userConfiguration[rule.field];
 
-        return (
-          Array.isArray(rule.value) && rule.value.indexOf(fieldValue) === -1
-        );
+        if (!Array.isArray(rule.value)) return false;
+        return rule.value.indexOf(fieldValue) === -1;
       }
 
       default:
diff --git a/packages/core/src/index.ts b/packages/core/src/index.ts
index dbfffca..f051d0d 100644
--- a/packages/core/src/index.ts
+++ b/packages/core/src/index.ts
@@ -16,7 +16,7 @@ const createUserContext = (
   const evaluate = (flagKey: string): string | boolean => {
     const flagConfig = flagsConfig.find((f) => f.key === flagKey);
     if (!flagConfig) return false;
-    if (flagConfig.status === "disabled") return false;
+    if (flagConfig.status !== "enabled") return false;
 
     return evaluateFlag(flagConfig, _userConfiguration);
   };