Expose turn token usage in the SDK (#4700)

It's present on the event, add it to the final result as well.

sdk/typescript/src/index.ts

@@ -9,6 +9,7 @@ export type {
   ItemCompletedEvent,
   ThreadError,
   ThreadErrorEvent,
+  Usage,
 } from "./events";
 export type {
   ThreadItem,

sdk/typescript/src/thread.ts

@@ -1,5 +1,5 @@
 import { CodexOptions } from "./codexOptions";
-import { ThreadEvent } from "./events";
+import { ThreadEvent, Usage } from "./events";
 import { CodexExec } from "./exec";
 import { ThreadItem } from "./items";
 import { ThreadOptions } from "./threadOptions";
@@ -8,6 +8,7 @@ import { ThreadOptions } from "./threadOptions";
 export type Turn = {
   items: ThreadItem[];
   finalResponse: string;
+  usage: Usage | null;
 };
 
 /** Alias for `Turn` to describe the result of `run()`. */
@@ -85,14 +86,17 @@ export class Thread {
     const generator = this.runStreamedInternal(input);
     const items: ThreadItem[] = [];
     let finalResponse: string = "";
+    let usage: Usage | null = null;
     for await (const event of generator) {
       if (event.type === "item.completed") {
         if (event.item.type === "agent_message") {
           finalResponse = event.item.text;
         }
         items.push(event.item);
+      } else if (event.type === "turn.completed") {
+        usage = event.usage;
       }
     }
-    return { items, finalResponse };
+    return { items, finalResponse, usage };
   }
 }

sdk/typescript/tests/responsesProxy.ts

@@ -3,6 +3,22 @@ import http from "node:http";
 const DEFAULT_RESPONSE_ID = "resp_mock";
 const DEFAULT_MESSAGE_ID = "msg_mock";
 
+type ResponseCompletedUsage = {
+  input_tokens: number;
+  input_tokens_details: { cached_tokens: number } | null;
+  output_tokens: number;
+  output_tokens_details: { reasoning_tokens: number } | null;
+  total_tokens: number;
+};
+
+const DEFAULT_COMPLETED_USAGE: ResponseCompletedUsage = {
+  input_tokens: 42,
+  input_tokens_details: { cached_tokens: 12 },
+  output_tokens: 5,
+  output_tokens_details: null,
+  total_tokens: 47,
+};
+
 type SseEvent = {
   type: string;
   [key: string]: unknown;
@@ -157,17 +173,26 @@ export function assistantMessage(text: string, itemId: string = DEFAULT_MESSAGE_
   };
 }
 
-export function responseCompleted(responseId: string = DEFAULT_RESPONSE_ID): SseEvent {
+export function responseCompleted(
+  responseId: string = DEFAULT_RESPONSE_ID,
+  usage: ResponseCompletedUsage = DEFAULT_COMPLETED_USAGE,
+): SseEvent {
+  const inputDetails = usage.input_tokens_details
+    ? { ...usage.input_tokens_details }
+    : null;
+  const outputDetails = usage.output_tokens_details
+    ? { ...usage.output_tokens_details }
+    : null;
   return {
     type: "response.completed",
     response: {
       id: responseId,
       usage: {
-        input_tokens: 0,
-        input_tokens_details: null,
-        output_tokens: 0,
-        output_tokens_details: null,
-        total_tokens: 0,
+        input_tokens: usage.input_tokens,
+        input_tokens_details: inputDetails,
+        output_tokens: usage.output_tokens,
+        output_tokens_details: outputDetails,
+        total_tokens: usage.total_tokens,
       },
     },
   };

sdk/typescript/tests/run.test.ts

@@ -38,6 +38,11 @@ describe("Codex", () => {
         },
       ];
       expect(result.items).toEqual(expectedItems);
+      expect(result.usage).toEqual({
+        cached_input_tokens: 12,
+        input_tokens: 42,
+        output_tokens: 5,
+      });
       expect(thread.id).toEqual(expect.any(String));
     } finally {
       await close();

sdk/typescript/tests/runStreamed.test.ts

@@ -52,9 +52,9 @@ describe("Codex", () => {
         {
           type: "turn.completed",
           usage: {
-            cached_input_tokens: 0,
-            input_tokens: 0,
-            output_tokens: 0,
+            cached_input_tokens: 12,
+            input_tokens: 42,
+            output_tokens: 5,
           },
         },
       ]);