[BUG] Claude code working very poorly when internet connection is done via tethering

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?

Environment

• Claude Code: 2.1.220

• macOS: 27.x (Apple Silicon) (yes, this is beta. The issue was reproducible with macOS 26.5 too)

• iPhone 17 Pro

• iOS 26.5.2

• Connection: iPhone USB tethering (en7)

Problem

Claude Code frequently reports:

Unable to connect to API (ECONNRESET)

Retrying in 2s · attempt N/10

The issue is reproducible while using USB tethering.

Observations

• Happens in a completely fresh claude --debug session.

• Happens in interactive mode and Plan mode.

• Happens with Sonnet and Opus.

• Restarting Claude does not resolve it.

• WireGuard VPN does not reliably resolve it.

Does NOT reproduce

• Hotel Wi-Fi
• Wi-Fi at home

• Browsing

• GitHub

• git push/pull

• curl to api.anthropic.com

• ChatGPT

Diagnostics

Repeated Node.js HTTPS requests to https://api.anthropic.com completed successfully:

• Node 24.10.0

• 50 consecutive requests

• 0 ECONNRESET

• Only expected HTTP 404 responses

This suggests general HTTPS connectivity is healthy while Claude Code alone experiences repeated ECONNRESET failures.

Happy to provide debug logs if needed.

What Should Happen?

While the internet connection is fast and stable, i would expect that claude code works in this environment...and working remotely is a very common scenario these days.

Error Messages/Logs

Not much logging available. Just see:

API Error: Unable to connect to API (ECONNRESET)

retries 10 times and stops.

All this while i do other network related operations that work fine.

Steps to Reproduce

1. Start internet connection via tethering
2. Perform network test: ping 40ms, down: ~250Mbit/s, up: ~50Mbit/s
3. Start fresh terminal
4. Start claude in a folder
5. Paste or write prompt
6. See error

Claude Model

Not sure / Multiple models

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

2.1.220

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_