diff --git a/src/api/providers/__tests__/openai-native-tools.spec.ts b/src/api/providers/__tests__/openai-native-tools.spec.ts
new file mode 100644
index 0000000000..1a3b93b9c2
--- /dev/null
+++ b/src/api/providers/__tests__/openai-native-tools.spec.ts
@@ -0,0 +1,77 @@
+import OpenAI from "openai"
+
+import { OpenAiHandler } from "../openai"
+
+describe("OpenAiHandler native tools", () => {
+	it("includes tools in request when custom model info lacks supportsNativeTools (regression test)", async () => {
+		const mockCreate = vi.fn().mockImplementationOnce(() => ({
+			[Symbol.asyncIterator]: async function* () {
+				yield {
+					choices: [{ delta: { content: "Test response" } }],
+				}
+			},
+		}))
+
+		// Set openAiCustomModelInfo WITHOUT supportsNativeTools to simulate
+		// a user-provided custom model info that doesn't specify native tool support.
+		// The getModel() fix should merge NATIVE_TOOL_DEFAULTS to ensure
+		// supportsNativeTools defaults to true.
+		const handler = new OpenAiHandler({
+			openAiApiKey: "test-key",
+			openAiBaseUrl: "https://example.com/v1",
+			openAiModelId: "test-model",
+			openAiCustomModelInfo: {
+				maxTokens: 4096,
+				contextWindow: 128000,
+			},
+		} as unknown as import("../../../shared/api").ApiHandlerOptions)
+
+		// Patch the OpenAI client call
+		const mockClient = {
+			chat: {
+				completions: {
+					create: mockCreate,
+				},
+			},
+		} as unknown as OpenAI
+		;(handler as unknown as { client: OpenAI }).client = mockClient
+
+		const tools: OpenAI.Chat.ChatCompletionTool[] = [
+			{
+				type: "function",
+				function: {
+					name: "test_tool",
+					description: "test",
+					parameters: { type: "object", properties: {} },
+				},
+			},
+		]
+
+		// Mimic the behavior in Task.attemptApiRequest() where tools are only
+		// included when modelInfo.supportsNativeTools is true. This is the
+		// actual regression path being tested - without the getModel() fix,
+		// supportsNativeTools would be undefined and tools wouldn't be passed.
+		const modelInfo = handler.getModel().info
+		const supportsNativeTools = modelInfo.supportsNativeTools ?? false
+
+		const stream = handler.createMessage("system", [], {
+			taskId: "test-task-id",
+			...(supportsNativeTools && { tools }),
+			...(supportsNativeTools && { toolProtocol: "native" as const }),
+		})
+		await stream.next()
+
+		expect(mockCreate).toHaveBeenCalledWith(
+			expect.objectContaining({
+				tools: expect.arrayContaining([
+					expect.objectContaining({
+						type: "function",
+						function: expect.objectContaining({ name: "test_tool" }),
+					}),
+				]),
+				parallel_tool_calls: false,
+			}),
+			expect.anything(),
+		)
+	})
+})
diff --git a/src/api/providers/openai.ts b/src/api/providers/openai.ts
index f63ee99dc2..7ab2b00524 100644
--- a/src/api/providers/openai.ts
+++ b/src/api/providers/openai.ts
@@ -6,6 +6,7 @@ import {
 	type ModelInfo,
 	azureOpenAiDefaultApiVersion,
 	openAiModelInfoSaneDefaults,
+	NATIVE_TOOL_DEFAULTS,
 	DEEP_SEEK_DEFAULT_TEMPERATURE,
 	OPENAI_AZURE_AI_INFERENCE_PATH,
 } from "@roo-code/types"
@@ -291,7 +292,13 @@ export class OpenAiHandler extends BaseProvider implements SingleCompletionHandl
 
 	override getModel() {
 		const id = this.options.openAiModelId ?? ""
-		const info = this.options.openAiCustomModelInfo ?? openAiModelInfoSaneDefaults
+		// Ensure OpenAI-compatible models default to supporting native tool calling.
+		// This is required for [`Task.attemptApiRequest()`](src/core/task/Task.ts:3817) to
+		// include tool definitions in the request.
+		const info: ModelInfo = {
+			...NATIVE_TOOL_DEFAULTS,
+			...(this.options.openAiCustomModelInfo ?? openAiModelInfoSaneDefaults),
+		}
 		const params = getModelParams({ format: "openai", modelId: id, model: info, settings: this.options })
 		return { id, info, ...params }
 	}