feat: treat built-in Responses tools as first-class bridge entries

Author: ndycode

lib/request/request-transformer.ts

@@ -421,6 +421,12 @@ function extractRuntimeToolNames(tools: unknown): string[] {
 	for (const tool of tools) {
 		if (!tool || typeof tool !== "object") continue;
 
+		const toolType = (tool as { type?: unknown }).type;
+		if (typeof toolType === "string" && toolType.trim() && toolType !== "function") {
+			names.push(toolType);
+			continue;
+		}
+
 		const directName = (tool as { name?: unknown }).name;
 		if (typeof directName === "string" && directName.trim()) {
 			names.push(directName);

test/request-transformer.test.ts

@@ -754,6 +754,22 @@ describe('Request Transformer Module', () => {
 		it('should return undefined for undefined input', () => {
 			expect(addCodexBridgeMessage(undefined, true)).toBeUndefined();
 		});
+
+		it('should list built-in Responses tools in the runtime manifest', () => {
+			const input: InputItem[] = [
+				{ type: 'message', role: 'user', content: 'hello' },
+			];
+			const result = addCodexBridgeMessage(input, true, [
+				{ type: 'web_search_preview', search_context_size: 'medium' },
+				{ type: 'file_search', vector_store_ids: ['vs_123'] },
+				{ type: 'function', function: { name: 'read_file' } },
+			]);
+
+			const bridgeText = (result?.[0].content as any)[0].text;
+			expect(bridgeText).toContain('`web_search_preview`');
+			expect(bridgeText).toContain('`file_search`');
+			expect(bridgeText).toContain('`read_file`');
+		});
 	});
 
 		describe('transformRequestBody', () => {
@@ -1449,6 +1465,27 @@ describe('Request Transformer Module', () => {
 			expect(result.max_completion_tokens).toBeUndefined();
 		});
 
+		it('should preserve newer Responses passthrough fields', async () => {
+			const body: RequestBody = {
+				model: 'gpt-5',
+				input: [],
+				previous_response_id: 'resp_123',
+				parallel_tool_calls: true,
+				service_tier: 'auto',
+				metadata: { source: 'test-suite' },
+				tool_choice: 'auto',
+				truncation: 'auto',
+			};
+			const result = await transformRequestBody(body, codexInstructions);
+
+			expect(result.previous_response_id).toBe('resp_123');
+			expect(result.parallel_tool_calls).toBe(true);
+			expect(result.service_tier).toBe('auto');
+			expect(result.metadata).toEqual({ source: 'test-suite' });
+			expect(result.tool_choice).toBe('auto');
+			expect(result.truncation).toBe('auto');
+		});
+
 		it('should normalize minimal to low for gpt-5-codex', async () => {
 			const body: RequestBody = {
 				model: 'gpt-5-codex',

test/tool-utils.test.ts

@@ -13,6 +13,16 @@ describe("cleanupToolDefinitions", () => {
     expect(cleanupToolDefinitions(tools)).toEqual(tools);
   });
 
+  it("preserves built-in Responses tools unchanged", () => {
+    const tools = [
+      { type: "web_search_preview", search_context_size: "medium" },
+      { type: "file_search", vector_store_ids: ["vs_123"] },
+      { type: "computer_use_preview", environment: "browser" },
+    ];
+
+    expect(cleanupToolDefinitions(tools)).toEqual(tools);
+  });
+
   it("filters required array to only existing properties", () => {
     const tools = [{
       type: "function",