[BUG] git push fails with HTTP 503 on git-receive-pack endpoint via the Claude Code proxy

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?

git push fails with HTTP 503 through the Claude Code git proxy. Every push attempt returns:

error: RPC failed; HTTP 503 curl 22 The requested URL returned error: 503
send-pack: unexpected disconnect while reading sideband packet
fatal: the remote end hung up unexpectedly

This has persisted across multiple Claude Code sessions (several hours). git fetch and reads work fine — only writes (git-receive-pack) are broken.

What Should Happen?

git push should successfully push committed changes to the remote branch via the Claude Code proxy. Currently the only workaround is using MCP GitHub tools (push_files) which bypass the proxy entirely.

Error Messages/Logs

error: RPC failed; HTTP 503 curl 22 The requested URL returned error: 503
send-pack: unexpected disconnect while reading sideband packet
fatal: the remote end hung up unexpectedly
Everything up-to-date

Proxy endpoint: http://127.0.0.1:<port>/git/<owner>/<repo>
Cloudflare / api.anthropic.com upstream returning 503 on git-receive-pack

Steps to Reproduce

1. Open a Claude Code session with a GitHub-connected repository
2. Make changes to files and create a git commit
3. Run: git push -u origin <branch-name>
4. Error appears immediately: "HTTP 503 curl 22 The requested URL returned error: 503"
5. Issue persists across all new Claude Code sessions
6. git fetch and git pull work correctly — only push (git-receive-pack) fails

Claude Model

Not sure / Multiple models

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

4.7

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Other

Additional Information

_No response_