[BUG] claude.ai/install.sh returns 403 — Cloudflare challenge blocks Docker/CI installs

[aa-shalin]

Preflight Checklist

• I have searched existing issues and this hasn't been reported yet
• This is a single bug report
• I am using the latest version of Claude Code

What's Wrong?

https://claude.ai/install.sh returns HTTP 403 when fetched from Docker builds or CI environments (GitHub Actions). Cloudflare is serving a browser challenge instead of the install script, making the documented install method unusable in automated environments.

What Should Happen?

curl -fsSL https://claude.ai/install.sh | bash should work in non-interactive environments (Docker builds, GitHub Actions, CI pipelines) as documented.

Error Messages/Logs

$ curl -fsSL https://claude.ai/install.sh | bash
curl: (22) The requested URL returned error: 403

$ curl -sI https://claude.ai/install.sh
HTTP/2 403
cf-mitigated: challenge
content-type: text/html; charset=UTF-8

Steps to Reproduce

1. In any Dockerfile:

   FROM node:20-slim
   RUN curl -fsSL https://claude.ai/install.sh | bash

2. docker build .
3. Build fails at the curl step with exit code 22 (HTTP 403)

Same issue from GitHub Actions runners and any non-browser curl request.

Claude Model

Not sure / Multiple models

Is this a regression?

Yes, this worked in a previous version

Last Working Version

Unknown — worked before Cloudflare challenge was enabled on claude.ai

Claude Code Version

1.0.202 (Claude Code)

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Non-interactive/CI environment

Additional Information

Response headers confirm Cloudflare challenge mitigation:

cf-mitigated: challenge
accept-ch: Sec-CH-UA-Bitness, Sec-CH-UA-Arch, ...

Workaround: Install via npm instead: npm install -g @anthropic-ai/claude-code

This is impacting our Docker builds in GitHub Actions. The Cloudflare WAF rule appears to not distinguish automated installs from bot traffic.

[aa-shalin]

@claude can you address this?

[github-actions]

Found 3 possible duplicate issues:

1. OAuth login fails from Hetzner VPS — Cloudflare JS challenge blocks token exchange #21678
2. OAuth login fails due to Cloudflare challenge race condition — auth login / setup-token broken during elevated CF protection #33269
3. Claude Code cannot authenticate from Contabo VPS - Cloudflare blocking claude.ai #36201

This issue will be automatically closed as a duplicate in 3 days.

• If your issue is a duplicate, please close it and 👍 the existing issue instead
• To prevent auto-closure, add a comment or 👎 this comment

🤖 Generated with Claude Code

[aa-shalin]

This isn't a duplicate. It doesn't have anything to do with auth.

[wiedenmeier]

Seeing this as well on github actions - potential workaround may be installing claude code via brew, but would strongly prefer to continue using the current https://claude.ai/install.sh approach if possible

[smartwatermelon]

Github actions are failing:

Adding marketplace: https://github.com/anthropics/claude-code.git
Error: Action failed with error: Failed to add marketplace 'https://github.com/anthropics/claude-code.git': Executable not found in $PATH: "claude"
Error: Process completed with exit code 1.

[aa-shalin]

This works curl -fsSL https://downloads.claude.ai/claude-code-releases/bootstrap.sh | bash

[chrislloyd]

Thanks for the report, this should be fixed now.

[github-actions]

This issue has been automatically locked since it was closed and has not had any activity for 7 days. If you're experiencing a similar issue, please file a new issue and reference this one if it's relevant.