[BUG] Claude.ai can't access private Github repo under "Add content from GitHub" in Project

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?

Claude.ai Projects cannot access a private GitHub repository despite the Claude GitHub App being fully installed and authorized on the GitHub account.

When adding a private repository URL to a Project's knowledge section, the error message appears:

"Claude cannot access that resource. If you know that it exists, you may first need to grant or request access here."

Following the link and granting access does not resolve the issue. The error persists regardless of permission scope.

What Should Happen?

After granting the Claude GitHub App access to a private repository (either via "All repositories" or "Select repositories"), the repository should be accessible and indexable in Claude Projects.

Error Messages/Logs

Claude cannot access that resource. If you know that it exists, you may first need to grant or request access [here](https://github.com/apps/claude/installations/select_target).

Steps to Reproduce

1. Go to claude.ai and open a Project
2. In the Project knowledge section, click "+" → "Add from GitHub"
3. Enter the URL of a private repository
4. Observe the warning — follow the link to install/authorize the Claude GitHub App
5. Grant access (tested with both "All repositories" and "Only select repositories" with the specific repo selected)
6. Return to Claude and attempt to add the repo again
7. Error persists: "Claude cannot access that resource"

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.74

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

• Platform: claude.ai (web) — Projects GitHub integration
• Note: This is NOT a Claude Code CLI issue — this is the GitHub integration within claude.ai Projects
• Repository type: Private repository on a personal GitHub account

This appears to be the same backend indexing issue described in #12839, #18467, and #27155. Those reports suggest that personal account private repositories are not being correctly indexed on Anthropic's backend, even when the GitHub App has been granted full access.

Requesting a backend repo index reset or sync for my account.