[BUG] Claude Desktop generates broken GitHub asset URLs when embedding images

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?

Description

When using Claude Desktop to embed images in GitHub issues/comments, Claude Desktop attempts to pre-construct GitHub asset URLs using descriptive filenames, which results in broken links.

Actual Behavior

Claude Desktop generates an image tag with a descriptive filename in the asset URL:

<img width="1161" height="660" alt="Image" src="https://github.com/user-attachments/assets/Acme_Report" />


### What Should Happen?

## Expected Behavior

Claude Desktop should either:
1. Wait for the image to be uploaded to GitHub first, then use the generated asset URL
2. Inform the user that images must be manually uploaded to GitHub
3. Handle the upload process correctly through the GitHub API

### Error Messages/Logs

```shell

Steps to Reproduce

1. Use Claude Desktop to add content to a GitHub issue
2. Ask Claude Desktop to embed an image in the issue
3. Claude Desktop generates an img tag with a descriptive filename in the GitHub assets URL
4. The resulting link is broken

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.25 (Claude Code)

Platform

Anthropic API

Operating System

Other Linux

Terminal/Shell

Xterm

Additional Information

This URL is broken because GitHub:

• Generates unique hash/UUID filenames when assets are uploaded (e.g., a1b2c3d4-e5f6-7890-abcd-ef1234567890)
• Does not allow pre-specifying asset filenames
• Only accepts URLs with its generated IDs