fix(api): relax request config option constraints

Author: easonliang28

src/api/providers/__tests__/request-config-builder.spec.ts

@@ -31,6 +31,12 @@ describe("RequestConfigBuilder", () => {
 			expect(builder.getCleanup()).toBeTypeOf("function")
 			expect(() => builder.getCleanup()()).not.toThrow()
 		})
+
+		test("should ignore undefined values from defaultOptions", () => {
+			const builder = new RequestConfigBuilder({ modelId: undefined })
+
+			expect(builder.build()).toBeUndefined()
+		})
 	})
 
 	describe("addAbortSignal", () => {
@@ -316,6 +322,12 @@ describe("RequestConfigBuilder", () => {
 			expect(result.modelId).toBe("test-model")
 		})
 
+		test("should treat undefined extraOptions values as absent", () => {
+			const result = RequestConfigBuilder.fromMetadata(undefined, { signal: undefined })
+
+			expect(result).toBeUndefined()
+		})
+
 		test("should not set signal when metadata.abortSignal is undefined", () => {
 			const metadata: ApiHandlerCreateMessageMetadata = { taskId: "test-task" }
 			const extraOptions = { modelId: "test-model" }
@@ -577,5 +589,21 @@ describe("RequestConfigBuilder", () => {
 			expect(config.timeout).toBe(30000)
 			expect(config.retryCount).toBe(3)
 		})
+
+		test("should accept interface-based options without an index signature", () => {
+			interface SdkOptions {
+				modelId?: string
+				signal?: AbortSignal
+				headers?: Record<string, string>
+				maxTokens?: number
+			}
+
+			const builder = new RequestConfigBuilder<SdkOptions>({ modelId: "default-model" })
+			builder.setOption("maxTokens", 2000)
+
+			const config = builder.build() as SdkOptions
+			expect(config.modelId).toBe("default-model")
+			expect(config.maxTokens).toBe(2000)
+		})
 	})
 })

src/api/providers/config-builder/request-config-builder.ts

@@ -11,17 +11,23 @@ import { mergeAbortSignalAndTimeout, mergeAbortSignals } from "../utils/abort-si
  * - Header merging
  * - Static factory methods
  */
-type RequestConfigOptions = {
+type RequestConfigOptionsBase = object & {
 	headers?: Record<string, string>
 	signal?: AbortSignal
-} & Record<string, unknown>
+}
+
+type RequestConfigOptions = RequestConfigOptionsBase & Record<string, unknown>
 
-export class RequestConfigBuilder<TOptions extends RequestConfigOptions = RequestConfigOptions> {
+export class RequestConfigBuilder<TOptions extends RequestConfigOptionsBase = RequestConfigOptions> {
 	protected options: Partial<TOptions>
 	private cleanupFn: () => void = () => {}
 
 	constructor(defaultOptions?: Partial<TOptions>) {
-		this.options = defaultOptions ? { ...defaultOptions } : {}
+		this.options = defaultOptions
+			? (Object.fromEntries(
+					Object.entries(defaultOptions).filter(([, value]) => value !== undefined),
+				) as Partial<TOptions>)
+			: {}
 	}
 
 	/**
@@ -142,7 +148,7 @@ export class RequestConfigBuilder<TOptions extends RequestConfigOptions = Reques
 	 * @param extraOptions - Additional options to merge
 	 * @returns The built configuration or undefined if empty
 	 */
-	static fromMetadata<TOptions extends RequestConfigOptions = RequestConfigOptions>(
+	static fromMetadata<TOptions extends RequestConfigOptionsBase = RequestConfigOptions>(
 		metadata?: ApiHandlerCreateMessageMetadata,
 		extraOptions?: Partial<TOptions>,
 	): TOptions | undefined {