diff --git a/packages/aiCore/src/core/providers/__tests__/types.test.ts b/packages/aiCore/src/core/providers/__tests__/types.test.ts
new file mode 100644
index 0000000000..389d83ff90
--- /dev/null
+++ b/packages/aiCore/src/core/providers/__tests__/types.test.ts
@@ -0,0 +1,275 @@
+/**
+ * Provider Types - Type-level Tests
+ * Tests type utilities and type inference for provider extensions
+ */
+
+import type { ProviderV3 } from '@ai-sdk/provider'
+import { describe, expectTypeOf, it } from 'vitest'
+
+import type { ProviderExtensionConfig } from '../core/ProviderExtension'
+import type {
+  CoreProviderSettingsMap,
+  ExtensionConfigToIdResolutionMap,
+  ExtractExtensionIds,
+  ExtractProviderIds,
+  StringKeys,
+  UnionToIntersection
+} from '../types'
+
+describe('Type Utilities', () => {
+  describe('StringKeys<T>', () => {
+    it('should extract only string keys from object type', () => {
+      type TestObj = { foo: 1; bar: 2; 0: 3; 1: 4 }
+      type Result = StringKeys<TestObj>
+
+      expectTypeOf<Result>().toEqualTypeOf<'foo' | 'bar'>()
+    })
+
+    it('should return never for object with no string keys', () => {
+      type TestObj = { 0: 'a'; 1: 'b' }
+      type Result = StringKeys<TestObj>
+
+      expectTypeOf<Result>().toEqualTypeOf<never>()
+    })
+
+    it('should handle empty object', () => {
+      type Result = StringKeys<{}>
+
+      expectTypeOf<Result>().toEqualTypeOf<never>()
+    })
+
+    it('should preserve literal string keys', () => {
+      type TestObj = { openai: 1; anthropic: 2; google: 3 }
+      type Result = StringKeys<TestObj>
+
+      expectTypeOf<Result>().toEqualTypeOf<'openai' | 'anthropic' | 'google'>()
+    })
+  })
+
+  describe('UnionToIntersection<U>', () => {
+    it('should convert union to intersection', () => {
+      type Union = { a: 1 } | { b: 2 }
+      type Result = UnionToIntersection<Union>
+
+      expectTypeOf<Result>().toEqualTypeOf<{ a: 1 } & { b: 2 }>()
+    })
+
+    it('should handle single type', () => {
+      type Single = { a: 1 }
+      type Result = UnionToIntersection<Single>
+
+      expectTypeOf<Result>().toEqualTypeOf<{ a: 1 }>()
+    })
+  })
+
+  describe('ExtractProviderIds<TConfig>', () => {
+    it('should extract base name', () => {
+      type Config = { name: 'openai' }
+      type Result = ExtractProviderIds<Config>
+
+      expectTypeOf<Result>().toEqualTypeOf<'openai'>()
+    })
+
+    it('should extract name and aliases', () => {
+      type Config = { name: 'anthropic'; aliases: readonly ['claude'] }
+      type Result = ExtractProviderIds<Config>
+
+      expectTypeOf<Result>().toEqualTypeOf<'anthropic' | 'claude'>()
+    })
+
+    it('should extract name and variants', () => {
+      type Config = { name: 'openai'; variants: readonly [{ suffix: 'chat' }] }
+      type Result = ExtractProviderIds<Config>
+
+      expectTypeOf<Result>().toEqualTypeOf<'openai' | 'openai-chat'>()
+    })
+
+    it('should extract name, aliases, and variants', () => {
+      type Config = {
+        name: 'azure'
+        aliases: readonly ['azure-openai']
+        variants: readonly [{ suffix: 'responses' }]
+      }
+      type Result = ExtractProviderIds<Config>
+
+      expectTypeOf<Result>().toEqualTypeOf<'azure' | 'azure-openai' | 'azure-responses'>()
+    })
+
+    it('should handle multiple variants', () => {
+      type Config = {
+        name: 'openai'
+        variants: readonly [{ suffix: 'chat' }, { suffix: 'responses' }]
+      }
+      type Result = ExtractProviderIds<Config>
+
+      expectTypeOf<Result>().toEqualTypeOf<'openai' | 'openai-chat' | 'openai-responses'>()
+    })
+  })
+
+  describe('ExtensionConfigToIdResolutionMap<TConfig>', () => {
+    it('should map base name to itself', () => {
+      type Config = { name: 'openai' }
+      type Result = ExtensionConfigToIdResolutionMap<Config>
+
+      expectTypeOf<Result>().toEqualTypeOf<{ readonly openai: 'openai' }>()
+    })
+
+    it('should map aliases to base name', () => {
+      type Config = { name: 'anthropic'; aliases: readonly ['claude'] }
+      type Result = ExtensionConfigToIdResolutionMap<Config>
+
+      expectTypeOf<Result>().toEqualTypeOf<{
+        readonly anthropic: 'anthropic'
+        readonly claude: 'anthropic'
+      }>()
+    })
+
+    it('should map variants to themselves (self-referential)', () => {
+      type Config = { name: 'azure'; variants: readonly [{ suffix: 'responses' }] }
+      type Result = ExtensionConfigToIdResolutionMap<Config>
+
+      expectTypeOf<Result>().toEqualTypeOf<{
+        readonly azure: 'azure'
+        readonly 'azure-responses': 'azure-responses'
+      }>()
+    })
+
+    it('should handle combined aliases and variants correctly', () => {
+      type Config = {
+        name: 'azure'
+        aliases: readonly ['azure-openai']
+        variants: readonly [{ suffix: 'responses' }]
+      }
+      type Result = ExtensionConfigToIdResolutionMap<Config>
+
+      expectTypeOf<Result>().toEqualTypeOf<{
+        readonly azure: 'azure'
+        readonly 'azure-openai': 'azure'
+        readonly 'azure-responses': 'azure-responses'
+      }>()
+    })
+  })
+
+  describe('ExtractExtensionIds<T>', () => {
+    it('should extract IDs from extension with config property', () => {
+      type MockExtension = {
+        config: { name: 'test'; aliases: readonly ['test-alias'] }
+      }
+      type Result = ExtractExtensionIds<MockExtension>
+
+      expectTypeOf<Result>().toEqualTypeOf<'test' | 'test-alias'>()
+    })
+  })
+
+  describe('ExtensionToSettingsMap<T>', () => {
+    it('should map provider IDs to settings type', () => {
+      type MockSettings = { apiKey: string }
+      type MockConfig = { name: 'mock' }
+
+      // Simulate ProviderExtension structure
+      type MockExtension = {
+        config: MockConfig
+        // ProviderExtension<TSettings, TStorage, TProvider, TConfig>
+      } & { __settings: MockSettings }
+
+      // This tests the concept - actual implementation depends on ProviderExtension structure
+      type Result = { [K in ExtractProviderIds<MockConfig>]: MockSettings }
+
+      expectTypeOf<Result>().toEqualTypeOf<{ mock: MockSettings }>()
+    })
+  })
+
+  describe('CoreProviderSettingsMap', () => {
+    it('should include openai provider', () => {
+      expectTypeOf<CoreProviderSettingsMap>().toHaveProperty('openai')
+    })
+
+    it('should include anthropic provider', () => {
+      expectTypeOf<CoreProviderSettingsMap>().toHaveProperty('anthropic')
+    })
+
+    it('should include google provider', () => {
+      expectTypeOf<CoreProviderSettingsMap>().toHaveProperty('google')
+    })
+
+    it('should include azure provider', () => {
+      expectTypeOf<CoreProviderSettingsMap>().toHaveProperty('azure')
+    })
+
+    it('should include xai provider', () => {
+      expectTypeOf<CoreProviderSettingsMap>().toHaveProperty('xai')
+    })
+
+    it('should include deepseek provider', () => {
+      expectTypeOf<CoreProviderSettingsMap>().toHaveProperty('deepseek')
+    })
+
+    it('should include openrouter provider', () => {
+      expectTypeOf<CoreProviderSettingsMap>().toHaveProperty('openrouter')
+    })
+
+    it('should include aliases like claude', () => {
+      expectTypeOf<CoreProviderSettingsMap>().toHaveProperty('claude')
+    })
+
+    it('should include variants like openai-chat', () => {
+      expectTypeOf<CoreProviderSettingsMap>().toHaveProperty('openai-chat')
+    })
+
+    it('should include variants like azure-responses', () => {
+      expectTypeOf<CoreProviderSettingsMap>().toHaveProperty('azure-responses')
+    })
+  })
+})
+
+describe('ProviderExtensionConfig Type Constraints', () => {
+  it('should accept valid minimal config', () => {
+    type ValidConfig = ProviderExtensionConfig<{ apiKey: string }, {}, ProviderV3, 'test'>
+
+    // Should compile without errors
+    const config: ValidConfig = {
+      name: 'test',
+      create: () => ({}) as ProviderV3
+    }
+
+    expectTypeOf(config.name).toEqualTypeOf<'test'>()
+  })
+
+  it('should accept config with aliases', () => {
+    type ConfigWithAliases = {
+      name: 'anthropic'
+      aliases: readonly ['claude']
+      create: () => ProviderV3
+    }
+
+    const config: ConfigWithAliases = {
+      name: 'anthropic',
+      aliases: ['claude'] as const,
+      create: () => ({}) as ProviderV3
+    }
+
+    expectTypeOf(config.aliases).toEqualTypeOf<readonly ['claude']>()
+  })
+
+  it('should accept config with variants', () => {
+    type ConfigWithVariants = {
+      name: 'openai'
+      variants: readonly [{ suffix: 'chat'; name: string; transform: (p: ProviderV3) => ProviderV3 }]
+      create: () => ProviderV3
+    }
+
+    const config: ConfigWithVariants = {
+      name: 'openai',
+      variants: [
+        {
+          suffix: 'chat',
+          name: 'OpenAI Chat',
+          transform: (p) => p
+        }
+      ] as const,
+      create: () => ({}) as ProviderV3
+    }
+
+    expectTypeOf(config.variants[0].suffix).toEqualTypeOf<'chat'>()
+  })
+})