fix(openai-adapters): allow disabling stream_options for strict OpenAI-compatible endpoints

packages/config-yaml/src/schemas/models.ts

@@ -192,6 +192,7 @@ const baseModelFields = {
   promptTemplates: promptTemplatesSchema.optional(),
   useLegacyCompletionsEndpoint: z.boolean().optional(),
   useResponsesApi: z.boolean().optional(),
+  streamOptions: z.boolean().optional(),
   env: z
     .record(z.string(), z.union([z.string(), z.boolean(), z.number()]))
     .optional(),

packages/openai-adapters/src/apis/OpenAI.ts

@@ -50,7 +50,7 @@ export class OpenAIApi implements BaseLlmApi {
   }
   modifyChatBody<T extends ChatCompletionCreateParams>(body: T): T {
     // Add stream_options to include usage in streaming responses
-    if (body.stream) {
+    if (body.stream && this.config.streamOptions !== false) {
       (body as any).stream_options = { include_usage: true };
     }
 

packages/openai-adapters/src/test/openai-adapter.vitest.ts

@@ -1,4 +1,5 @@
-import { describe, vi } from "vitest";
+import { describe, expect, it, vi } from "vitest";
+import { OpenAIApi } from "../apis/OpenAI.js";
 import { createAdapterTests } from "./adapter-test-utils.js";
 
 // Mock the fetch package (not needed for OpenAI but required by the shared test utils)
@@ -25,4 +26,29 @@ describe("OpenAI Adapter Tests", () => {
       accept: "application/json",
     },
   });
+
+  it("includes streaming usage by default unless stream options are disabled", () => {
+    const body = {
+      model: "gpt-4",
+      messages: [{ role: "user" as const, content: "hello" }],
+      stream: true as const,
+    };
+    const defaultApi = new OpenAIApi({
+      provider: "openai",
+      apiKey: "test-api-key",
+    });
+    const disabledApi = new OpenAIApi({
+      provider: "openai",
+      apiKey: "test-api-key",
+      streamOptions: false,
+    });
+
+    expect(defaultApi.modifyChatBody({ ...body })).toHaveProperty(
+      "stream_options.include_usage",
+      true,
+    );
+    expect(disabledApi.modifyChatBody({ ...body })).not.toHaveProperty(
+      "stream_options",
+    );
+  });
 });

packages/openai-adapters/src/types.ts

@@ -31,6 +31,7 @@ export const BasePlusConfig = BaseConfig.extend({
 // OpenAI and compatible
 export const OpenAIConfigSchema = BasePlusConfig.extend({
   useResponsesApi: z.boolean().optional(),
+  streamOptions: z.boolean().optional(),
   provider: z.union([
     z.literal("openai"),
     z.literal("mistral"),