An abort/cancel mechanism exists for in-flight AI requests

When a user navigates away mid-generation or realizes their prompt was wrong, the model continues generating and billing you for every token — even though no user will ever read the output. Without an abort mechanism, you pay for the full completion on every abandoned session. On a model that generates 1,000-token responses at $0.01 per completion, even a 5% abandonment rate on 10,000 daily requests costs $50/day in tokens that were never seen. OWASP LLM10, CWE-770, and NIST AI RMF MANAGE 1.3 all require application-level controls to terminate runaway resource consumption.

Wire the stop() function from useChat to a visible cancel button that appears while generation is in progress. The Vercel AI SDK propagates the abort signal to the provider automatically.

// src/components/chat.tsx
import { useChat } from "ai/react";

export function Chat() {
  const { messages, input, handleInputChange, handleSubmit, isLoading, stop } = useChat();
  return (
    <form onSubmit={handleSubmit}>
      {messages.map(m => <div key={m.id}>{m.content}</div>)}
      <input value={input} onChange={handleInputChange} disabled={isLoading} />
      {isLoading
        ? <button type="button" onClick={stop}>Stop generating</button>
        : <button type="submit">Send</button>
      }
    </form>
  );
}

For manual implementations using the OpenAI SDK directly, pass signal: controller.signal to chat.completions.create and call controller.abort() on cancel. Verify by starting a long generation, clicking Stop, and confirming server logs show a partial token count rather than the full expected output.