diff --git a/packages/types/src/__tests__/provider-settings.test.ts b/packages/types/src/__tests__/provider-settings.test.ts
index 8277320289..93a74f3c42 100644
--- a/packages/types/src/__tests__/provider-settings.test.ts
+++ b/packages/types/src/__tests__/provider-settings.test.ts
@@ -39,6 +39,26 @@ describe("getApiProtocol", () => {
 		})
 	})
 
+	describe("Vercel AI Gateway provider", () => {
+		it("should return 'anthropic' for vercel-ai-gateway provider with anthropic models", () => {
+			expect(getApiProtocol("vercel-ai-gateway", "anthropic/claude-3-opus")).toBe("anthropic")
+			expect(getApiProtocol("vercel-ai-gateway", "anthropic/claude-3.5-sonnet")).toBe("anthropic")
+			expect(getApiProtocol("vercel-ai-gateway", "ANTHROPIC/claude-sonnet-4")).toBe("anthropic")
+			expect(getApiProtocol("vercel-ai-gateway", "anthropic/claude-opus-4.1")).toBe("anthropic")
+		})
+
+		it("should return 'openai' for vercel-ai-gateway provider with non-anthropic models", () => {
+			expect(getApiProtocol("vercel-ai-gateway", "openai/gpt-4")).toBe("openai")
+			expect(getApiProtocol("vercel-ai-gateway", "google/gemini-pro")).toBe("openai")
+			expect(getApiProtocol("vercel-ai-gateway", "meta/llama-3")).toBe("openai")
+			expect(getApiProtocol("vercel-ai-gateway", "mistral/mixtral")).toBe("openai")
+		})
+
+		it("should return 'openai' for vercel-ai-gateway provider without model", () => {
+			expect(getApiProtocol("vercel-ai-gateway")).toBe("openai")
+		})
+	})
+
 	describe("Other providers", () => {
 		it("should return 'openai' for non-anthropic providers regardless of model", () => {
 			expect(getApiProtocol("openrouter", "claude-3-opus")).toBe("openai")
diff --git a/packages/types/src/provider-settings.ts b/packages/types/src/provider-settings.ts
index 8941e4cdd8..eb404f7129 100644
--- a/packages/types/src/provider-settings.ts
+++ b/packages/types/src/provider-settings.ts
@@ -453,6 +453,11 @@ export const getApiProtocol = (provider: ProviderName | undefined, modelId?: str
 		return "anthropic"
 	}
 
+	// Vercel AI Gateway uses anthropic protocol for anthropic models
+	if (provider && provider === "vercel-ai-gateway" && modelId && modelId.toLowerCase().startsWith("anthropic/")) {
+		return "anthropic"
+	}
+
 	return "openai"
 }