[BUG] VS Code Extension v2.1.63 causes massive outbound network traffic spike (30GB+ per day) due to runaway processes

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

The Claude VS Code extension (version 2.1.63) exhibits a critical bug that causes it to spawn multiple runaway processes, leading to massive outbound network traffic. In my case, this consumed 35GB of data overnight, far exceeding my normal 4GB daily usage.

Observation:

• Normal internet usage: ~4GB/day
• During incident: Spiked to 15GB in one day, then 35GB total by morning
• Starlink notified me of data cap exhaustion
• Chat requests inside the extension were not working during this period
• After investigation, the issue stopped immediately upon uninstalling the extension

Nethogs Evidence:
When running nethogs, I observed several concurrent processes of:
/home/<my_username>/.vscode/extensions/anthropic.claude-code-2.1.63-linux-x64/resources/native-binary/claude

These processes were making continuous outbound requests, which aligns with the "listener leak" pattern that version 2.1.63's release notes claimed to have fixed.

What Should Happen?

The extension should not generate network traffic when idle or when chat functionality is non-responsive. If there are background processes for telemetry or connectivity checks, they should:

• Run as a single instance, not multiple concurrent processes
• Respect user bandwidth and data caps
• Have built-in safeguards against runaway connection attempts
• Properly clean up listeners and child processes

Error Messages/Logs

No explicit error messages were shown in VS Code

Steps to Reproduce

1. Install Claude Code VS Code extension version 2.1.63
2. Use the extension normally for several days (or leave VS Code running with the extension active)
3. Monitor network usage (using nethogs, iftop, or system network monitors)
4. Observe that over time, multiple claude native-binary processes accumulate
5. Notice that data usage spikes dramatically (in my case, 15GB in one day)
6. Chat functionality may become unresponsive during this period

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.63 (VSCode extension)

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

VS Code integrated terminal

Additional Information

_No response_