diff --git a/frontend/src/features/models/composables/__tests__/useModelListLogic.spec.ts b/frontend/src/features/models/composables/__tests__/useModelListLogic.spec.ts
new file mode 100644
index 00000000..8203f248
--- /dev/null
+++ b/frontend/src/features/models/composables/__tests__/useModelListLogic.spec.ts
@@ -0,0 +1,131 @@
+import { describe, it, expect, beforeEach, vi } from 'vitest'
+import { useModelListLogic, formatDate, formatPercentage } from '../useModelListLogic'
+
+describe('useModelListLogic', () => {
+  let logic: ReturnType<typeof useModelListLogic>
+
+  beforeEach(() => {
+    logic = useModelListLogic()
+  })
+
+  describe('initialization', () => {
+    it('should initialize with default state', () => {
+      expect(logic.models.value).toHaveLength(3)
+      expect(logic.selectedModelId.value).toBe('1')
+      expect(logic.filters.search).toBe('')
+      expect(logic.filters.phase).toBe('')
+    })
+
+    it('should set screen state to LOADING on mount', () => {
+      expect(logic.screenState.value).toBe('LOADING')
+    })
+  })
+
+  describe('filtering', () => {
+    it('should filter models by search term', () => {
+      logic.filters.search = 'Alpha'
+      expect(logic.filteredModels.value).toHaveLength(1)
+      expect(logic.filteredModels.value[0].name).toBe('Hawkeye-Alpha')
+    })
+
+    it('should filter models by phase', () => {
+      logic.filters.phase = 'Mature'
+      expect(logic.filteredModels.value).toHaveLength(1)
+      expect(logic.filteredModels.value[0].phase).toBe('Mature')
+    })
+
+    it('should filter by both search and phase', () => {
+      logic.filters.search = 'Hawk'
+      logic.filters.phase = 'Validate'
+      expect(logic.filteredModels.value).toHaveLength(1)
+    })
+
+    it('should return all models when filters are empty', () => {
+      expect(logic.filteredModels.value).toHaveLength(3)
+    })
+
+    it('should be case-insensitive for search', () => {
+      logic.filters.search = 'alpha'
+      expect(logic.filteredModels.value).toHaveLength(1)
+    })
+  })
+
+  describe('model selection', () => {
+    it('should select model by id', () => {
+      logic.selectModel('2')
+      expect(logic.selectedModelId.value).toBe('2')
+    })
+
+    it('should return selected model', () => {
+      logic.selectModel('3')
+      expect(logic.selectedModel.value?.name).toBe('Gamma Arbitrage')
+    })
+
+    it('should return undefined for invalid model id', () => {
+      logic.selectModel('invalid')
+      expect(logic.selectedModel.value).toBeUndefined()
+    })
+  })
+
+  describe('search handling', () => {
+    it('should set isSearching flag', async () => {
+      expect(logic.isSearching.value).toBe(false)
+      const searchPromise = logic.handleSearch()
+      expect(logic.isSearching.value).toBe(true)
+      await searchPromise
+      expect(logic.isSearching.value).toBe(false)
+    })
+
+    it('should set screen state to LOADING during search', async () => {
+      expect(logic.screenState.value).not.toBe('LOADING')
+      const searchPromise = logic.handleSearch()
+      expect(logic.screenState.value).toBe('LOADING')
+      await searchPromise
+      expect(logic.screenState.value).toBe('READY')
+    })
+  })
+
+  describe('retry handling', () => {
+    it('should set screen state to LOADING on retry', async () => {
+      logic.screenState.value = 'ERROR'
+      const retryPromise = logic.handleRetry()
+      expect(logic.screenState.value).toBe('LOADING')
+      await retryPromise
+      expect(logic.screenState.value).toBe('READY')
+    })
+  })
+})
+
+describe('formatters', () => {
+  describe('formatDate', () => {
+    it('should format date to ko-KR locale', () => {
+      const date = '2026-06-15'
+      const result = formatDate(date)
+      expect(result).toMatch(/2026.*06.*15/)
+    })
+
+    it('should handle ISO date strings', () => {
+      const date = '2026-06-15T12:30:00Z'
+      const result = formatDate(date)
+      expect(result).toMatch(/2026.*06.*15/)
+    })
+  })
+
+  describe('formatPercentage', () => {
+    it('should format number as percentage', () => {
+      expect(formatPercentage(15.2)).toBe('15.20%')
+    })
+
+    it('should handle zero', () => {
+      expect(formatPercentage(0)).toBe('0.00%')
+    })
+
+    it('should handle decimal values', () => {
+      expect(formatPercentage(98.123)).toBe('98.12%')
+    })
+
+    it('should handle undefined/null as 0', () => {
+      expect(formatPercentage(null as any)).toBe('0.00%')
+    })
+  })
+})
diff --git a/frontend/src/features/models/composables/useModelListLogic.ts b/frontend/src/features/models/composables/useModelListLogic.ts
new file mode 100644
index 00000000..2d1ebadb
--- /dev/null
+++ b/frontend/src/features/models/composables/useModelListLogic.ts
@@ -0,0 +1,170 @@
+import { computed, reactive, ref, onMounted } from 'vue'
+import type { StandardScreenState } from '../../../shared/ui/contracts/screenContract'
+
+export interface Model {
+  modelId: string
+  name: string
+  phase: string
+  active: boolean
+  pbo: number
+  dsr: number
+  returnMtd: number
+  createdAt: string
+}
+
+export interface ModelFilters {
+  search: string
+  phase: string
+}
+
+/**
+ * useModelListLogic - Encapsulates all business logic for ModelList
+ * Extracted from God Component for testability and reusability
+ */
+export function useModelListLogic() {
+  // Screen state management
+  const screenState = ref<StandardScreenState>('READY')
+  const evidence = reactive({
+    asOf: new Date().toISOString(),
+    version: 'v60-T04-Contract',
+  })
+
+  // Mock data (replace with API call)
+  const mockModels: Model[] = [
+    {
+      modelId: '1',
+      name: 'Hawkeye-Alpha',
+      phase: 'Validate',
+      active: false,
+      pbo: 15.2,
+      dsr: 96.5,
+      returnMtd: 12.5,
+      createdAt: '2026-06-15',
+    },
+    {
+      modelId: '2',
+      name: 'Falcon-Beta',
+      phase: 'Review',
+      active: false,
+      pbo: 18.3,
+      dsr: 94.2,
+      returnMtd: 8.3,
+      createdAt: '2026-07-01',
+    },
+    {
+      modelId: '3',
+      name: 'Gamma Arbitrage',
+      phase: 'Mature',
+      active: true,
+      pbo: 8.5,
+      dsr: 98.1,
+      returnMtd: 18.7,
+      createdAt: '2026-05-10',
+    },
+  ]
+
+  // Models data
+  const models = ref<Model[]>(mockModels)
+  const selectedModelId = ref<string>(mockModels[0]?.modelId ?? '')
+
+  // Filters
+  const filters = reactive<ModelFilters>({
+    search: '',
+    phase: '',
+  })
+
+  // UI state
+  const isSearching = ref(false)
+
+  // Computed properties
+  const filteredModels = computed(() => {
+    return models.value.filter(m => {
+      const matchesSearch = m.name.toLowerCase().includes(filters.search.toLowerCase())
+      const matchesPhase = !filters.phase || m.phase === filters.phase
+      return matchesSearch && matchesPhase
+    })
+  })
+
+  const selectedModel = computed(() =>
+    models.value.find(m => m.modelId === selectedModelId.value)
+  )
+
+  // Methods
+  const selectModel = (id: string) => {
+    selectedModelId.value = id
+  }
+
+  const handleSearch = async () => {
+    isSearching.value = true
+    screenState.value = 'LOADING'
+    try {
+      // Simulate API call delay
+      await new Promise(resolve => setTimeout(resolve, 300))
+      screenState.value = 'READY'
+    } finally {
+      isSearching.value = false
+    }
+  }
+
+  const handleRetry = async () => {
+    screenState.value = 'LOADING'
+    try {
+      // Simulate retry delay
+      await new Promise(resolve => setTimeout(resolve, 400))
+      screenState.value = 'READY'
+    } catch {
+      screenState.value = 'ERROR'
+    }
+  }
+
+  const handleKeyDown = (e: KeyboardEvent) => {
+    if (e.key === 'F3') {
+      e.preventDefault()
+      handleSearch()
+    }
+  }
+
+  // Initialization
+  onMounted(() => {
+    screenState.value = 'LOADING'
+    setTimeout(() => {
+      screenState.value = 'READY'
+    }, 500)
+    window.addEventListener('keydown', handleKeyDown)
+  })
+
+  // Return public API
+  return {
+    // State
+    screenState,
+    evidence,
+    models,
+    selectedModelId,
+    filters,
+    isSearching,
+
+    // Computed
+    filteredModels,
+    selectedModel,
+
+    // Methods
+    selectModel,
+    handleSearch,
+    handleRetry,
+  }
+}
+
+/**
+ * Format utilities (can be extracted to separate formatter.ts)
+ */
+export function formatDate(dateString: string): string {
+  return new Date(dateString).toLocaleDateString('ko-KR', {
+    year: 'numeric',
+    month: '2-digit',
+    day: '2-digit',
+  })
+}
+
+export function formatPercentage(value: number): string {
+  return (value || 0).toFixed(2) + '%'
+}
diff --git a/src/KArtSell.Host/Security/RoleConstants.cs b/src/KArtSell.Host/Security/RoleConstants.cs
new file mode 100644
index 00000000..cd3412d3
--- /dev/null
+++ b/src/KArtSell.Host/Security/RoleConstants.cs
@@ -0,0 +1,38 @@
+namespace KArtSell.Host.Security;
+
+/// <summary>
+/// Role-Based Access Control (RBAC) constants
+/// Used in JWT claims and endpoint authorization
+/// </summary>
+public static class RoleConstants
+{
+    /// <summary>
+    /// System administrator - full access to all operations
+    /// </summary>
+    public const string Admin = "Admin";
+
+    /// <summary>
+    /// Security officer - access to security/audit operations
+    /// </summary>
+    public const string SecurityOfficer = "SecurityOfficer";
+
+    /// <summary>
+    /// Standard user - access to general operations
+    /// </summary>
+    public const string User = "User";
+
+    /// <summary>
+    /// Read-only access - view operations only
+    /// </summary>
+    public const string Viewer = "Viewer";
+
+    /// <summary>
+    /// All valid roles array (for validation/seeding)
+    /// </summary>
+    public static readonly string[] AllRoles = [Admin, SecurityOfficer, User, Viewer];
+
+    /// <summary>
+    /// Roles with audit log access
+    /// </summary>
+    public static readonly string[] AuditAccessRoles = [Admin, SecurityOfficer];
+}
diff --git a/tests/KArtSell.Host.UnitTests/Security/RoleBasedAccessControlTests.cs b/tests/KArtSell.Host.UnitTests/Security/RoleBasedAccessControlTests.cs
new file mode 100644
index 00000000..be43de6d
--- /dev/null
+++ b/tests/KArtSell.Host.UnitTests/Security/RoleBasedAccessControlTests.cs
@@ -0,0 +1,110 @@
+using System.IdentityModel.Tokens.Jwt;
+using System.Security.Claims;
+using System.Text;
+using KArtSell.Host.Security;
+using Microsoft.IdentityModel.Tokens;
+using Xunit;
+
+namespace KArtSell.Host.UnitTests.Security;
+
+public sealed class RoleBasedAccessControlTests
+{
+    private const string TestJwtKey = "test-secret-key-with-minimum-256-bits-length-requirement";
+    private const string TestIssuer = "test-issuer";
+    private const string TestAudience = "test-audience";
+
+    [Theory]
+    [InlineData(RoleConstants.Admin)]
+    [InlineData(RoleConstants.SecurityOfficer)]
+    [InlineData(RoleConstants.User)]
+    [InlineData(RoleConstants.Viewer)]
+    public void GenerateToken_WithValidRole_CreatesClaim(string role)
+    {
+        // Arrange
+        var username = "testuser";
+
+        // Act
+        var token = GenerateTestToken(username, role);
+        var handler = new JwtSecurityTokenHandler();
+        var jwtToken = handler.ReadToken(token) as JwtSecurityToken;
+
+        // Assert
+        var roleClaim = jwtToken?.Claims.FirstOrDefault(c => c.Type == ClaimTypes.Role);
+        Assert.NotNull(roleClaim);
+        Assert.Equal(role, roleClaim!.Value);
+    }
+
+    [Fact]
+    public void RoleConstants_ContainsAllExpectedRoles()
+    {
+        // Act & Assert
+        Assert.Contains(RoleConstants.Admin, RoleConstants.AllRoles);
+        Assert.Contains(RoleConstants.SecurityOfficer, RoleConstants.AllRoles);
+        Assert.Contains(RoleConstants.User, RoleConstants.AllRoles);
+        Assert.Contains(RoleConstants.Viewer, RoleConstants.AllRoles);
+        Assert.Equal(4, RoleConstants.AllRoles.Length);
+    }
+
+    [Fact]
+    public void AuditAccessRoles_IncludesAdminAndSecurityOfficer()
+    {
+        // Act & Assert
+        Assert.Contains(RoleConstants.Admin, RoleConstants.AuditAccessRoles);
+        Assert.Contains(RoleConstants.SecurityOfficer, RoleConstants.AuditAccessRoles);
+        Assert.Equal(2, RoleConstants.AuditAccessRoles.Length);
+    }
+
+    [Theory]
+    [InlineData(RoleConstants.Admin, true)]
+    [InlineData(RoleConstants.SecurityOfficer, true)]
+    [InlineData(RoleConstants.User, false)]
+    [InlineData(RoleConstants.Viewer, false)]
+    public void IsAuditAccessAllowed_ChecksRoleMembership(string role, bool expectedAccess)
+    {
+        // Act
+        var hasAccess = RoleConstants.AuditAccessRoles.Contains(role);
+
+        // Assert
+        Assert.Equal(expectedAccess, hasAccess);
+    }
+
+    [Fact]
+    public void ExtractRoleFromToken_ReturnsCorrectRole()
+    {
+        // Arrange
+        var username = "testuser";
+        var expectedRole = RoleConstants.Admin;
+        var token = GenerateTestToken(username, expectedRole);
+
+        // Act
+        var handler = new JwtSecurityTokenHandler();
+        var jwtToken = handler.ReadToken(token) as JwtSecurityToken;
+        var actualRole = jwtToken?.Claims.FirstOrDefault(c => c.Type == ClaimTypes.Role)?.Value;
+
+        // Assert
+        Assert.Equal(expectedRole, actualRole);
+    }
+
+    private static string GenerateTestToken(string username, string role)
+    {
+        var key = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(TestJwtKey));
+        var credentials = new SigningCredentials(key, SecurityAlgorithms.HmacSha256);
+
+        var claims = new[]
+        {
+            new Claim(ClaimTypes.NameIdentifier, username),
+            new Claim(ClaimTypes.Name, username),
+            new Claim(ClaimTypes.Role, role),
+            new Claim("auth_mode", "jwt")
+        };
+
+        var token = new JwtSecurityToken(
+            issuer: TestIssuer,
+            audience: TestAudience,
+            claims: claims,
+            expires: DateTime.UtcNow.AddMinutes(60),
+            signingCredentials: credentials);
+
+        return new JwtSecurityTokenHandler().WriteToken(token);
+    }
+}