[BUG] AbortController not respected

Environment

• Platform (select one):
• [x] Anthropic API
• [ ] AWS Bedrock
• [ ] Google Vertex AI
• [ ] Other: <!-- specify -->
• Claude CLI version: 1.0.43 (using SDK directly)
• Operating System: macOS 14.x
• Terminal: N/A (using Node.js SDK)

Bug Description

The SDK does not respect AbortController signals during query execution. When controller.abort() is called, the SDK continues processing and executing all queued tool calls to completion instead of stopping immediately.

Steps to Reproduce

1. Save the following as repro.mjs:

import { query } from "@anthropic-ai/claude-code/sdk.mjs";

// Minimal repro of AbortController not working
async function demonstrateBug() {
    const controller = new AbortController();
    let messageCount = 0;
    let abortedAt = null;

    console.log("Starting query that will use multiple tools...");

    try {
        for await (const message of query({
            prompt: "Create a todo list with 3 items, then read package.json, then list files in current directory",
            abortController: controller,
            options: {
                model: "claude-3-5-sonnet-20241022",
                maxTurns: 10,
                permissionMode: "bypassPermissions",
            },
        })) {
            messageCount++;
            console.log(`Message ${messageCount}: ${message.type}`);

            // Abort after receiving the first assistant message
            if (message.type === "assistant" && !abortedAt) {
                abortedAt = messageCount;
                console.log(`\n>>> ABORTING at message ${messageCount} <<<`);
                console.log(`>>> controller.signal.aborted before: 
  ${controller.signal.aborted}`);
                controller.abort();
                console.log(`>>> controller.signal.aborted after: 
  ${controller.signal.aborted}`);
                console.log(`>>> Expecting query to stop soon...\n`);
            }
        }

        console.log(`\nQuery completed. Total messages: ${messageCount}`);
        console.log(`Aborted at message: ${abortedAt}`);
        console.log(`Messages after abort: ${messageCount - abortedAt}`);
    } catch (error) {
        console.log("\nQuery threw error:", error.message);
        console.log("Error name:", error.name);
    }
}

// Run the demo
demonstrateBug().catch(console.error);

1. Run with: ANTHROPIC_API_KEY=your_key node repro.mjs

Expected Behavior

When controller.abort() is called, the query should stop immediately and throw an AbortError:

Starting query that will use multiple tools...
Message 1: system
Message 2: assistant

>>> ABORTING at message 2 <<<
>>> controller.signal.aborted before: false
>>> controller.signal.aborted after: true
>>> Expecting query to stop soon...

Query threw error: The operation was aborted
Error name: AbortError

Actual Behavior

The SDK continues executing all tools and completes the full query despite the abort signal:

Starting query that will use multiple tools...
Message 1: system
Message 2: assistant

>>> ABORTING at message 2 <<<
>>> controller.signal.aborted before:
  false
>>> controller.signal.aborted after:
  true
>>> Expecting query to stop soon...

Message 3: assistant
Message 4: assistant
Message 5: assistant
Message 6: user
Message 7: user
Message 8: user
Message 9: user
Message 10: assistant
Message 11: result

Query completed. Total messages: 11
Aborted at message: 2
Messages after abort: 9

Additional Context

Tested with:

• @anthropic-ai/claude-code: 1.0.43
• Node.js: v18.19.0 and v20.x