feat(ai): expose inputMessages and partialText in onAbort callback

.changeset/expose-abort-usage.md

@@ -0,0 +1,5 @@
+---
+'ai': patch
+---
+
+feat(ai): expose usage metrics in onAbort callback

content/docs/03-ai-sdk-core/50-error-handling.mdx

@@ -123,7 +123,11 @@ for await (const textPart of textStream) {
 
 The `onAbort` callback receives:
 
-- `steps`: An array of all completed steps before the abort
+- `steps`: All completed steps before the abort
+- `usage`: Token usage for the current (aborted) step, or `undefined` if not yet received
+- `totalUsage`: Aggregated usage across all completed steps plus the current step, or `undefined` if no usage data was received
+- `inputMessages`: The input messages for the current step, including prior step responses
+- `partialText`: The text being streamed at abort time, or `undefined` if no text was generated
 
 You can also handle abort events directly in the stream:
 

content/docs/07-reference/01-ai-sdk-core/02-stream-text.mdx

@@ -1799,6 +1799,30 @@ To see `streamText` in action, check out [these examples](#examples).
               type: 'Array<StepResult>',
               description: 'Details for all previously finished steps.',
             },
+            {
+              name: 'usage',
+              type: 'LanguageModelUsage | undefined',
+              description:
+                'Token usage for the current (aborted) step. undefined if the provider had not yet sent usage data before the abort.',
+            },
+            {
+              name: 'totalUsage',
+              type: 'LanguageModelUsage | undefined',
+              description:
+                'Aggregated token usage across all completed steps plus the current step. undefined if no usage data was received before the abort.',
+            },
+            {
+              name: 'inputMessages',
+              type: 'ModelMessage[]',
+              description:
+                'The input messages for the current step, including initial messages and all prior step responses. Empty array if abort fires before the first step starts.',
+            },
+            {
+              name: 'partialText',
+              type: 'string | undefined',
+              description:
+                'The text being streamed in the current step at abort time. undefined if no text had been generated. Resets at each step boundary.',
+            },
           ],
         },
       ],

examples/ai-functions/src/stream-text/openai/abort.ts

@@ -1,13 +1,44 @@
 import { openai } from '@ai-sdk/openai';
-import { streamText } from 'ai';
+import { isStepCount, streamText, tool } from 'ai';
+import { z } from 'zod';
 import { run } from '../../lib/run';
 
+const tools = {
+  add: tool({
+    description: 'Add two numbers',
+    inputSchema: z.object({ a: z.number(), b: z.number() }),
+    execute: async ({ a, b }) => ({ result: a + b }),
+  }),
+  multiply: tool({
+    description: 'Multiply two numbers',
+    inputSchema: z.object({ a: z.number(), b: z.number() }),
+    execute: async ({ a, b }) => ({ result: a * b }),
+  }),
+};
+
 run(async () => {
+  let stepCount = 0;
+
   try {
     const { textStream } = streamText({
-      model: openai('gpt-3.5-turbo'),
-      prompt: 'Write a short story about a robot learning to love:\n\n',
-      abortSignal: AbortSignal.timeout(3000),
+      model: openai('gpt-4o-mini'),
+      tools,
+      stopWhen: isStepCount(5),
+      prompt:
+        'First add 7 and 5. Then multiply the result by 6. Then write a very long detailed essay (at least 500 words) about the number you got.',
+      abortSignal: AbortSignal.timeout(10000),
+      onStepFinish(step) {
+        stepCount++;
+        console.log(`\n[Step ${stepCount} finished]`);
+        console.log('  Step usage:', step.usage);
+      },
+      onAbort({ usage, totalUsage, inputMessages, partialText }) {
+        console.log('\n\nStream aborted mid-generation.');
+        console.log('Current step usage:', usage);
+        console.log('Total usage:', totalUsage);
+        console.log('Input messages:', inputMessages);
+        console.log('Partial text:', partialText);
+      },
     });
 
     for await (const textPart of textStream) {