Cursor Incorrectly Modifies URLs in .mdc Files by Adding 'mdc:' Prefix

Support Bug Reports
1

:lady_beetle: Bug Description:
Cursor is automatically and incorrectly modifying URLs in .mdc files by changing https:// to mdc:https:/. This creates invalid URLs and breaks documentation links.

Example from planningmap.mdc file:

  • Original URL: https://gis.sauevald.ee/arcgis/rest/services
  • Modified by Cursor to: mdc:https:/gis.sauevald.ee/arcgis/rest/services

The issue affects all URLs in .mdc files, making them invalid and breaking external links in documentation.

:counterclockwise_arrows_button: Steps to Reproduce:

  1. Create or open a .mdc file in Cursor
  2. Add a URL starting with https://
  3. Save the file
  4. Observe that Cursor has automatically prefixed the URL with mdc: and removed a forward slash

:camera: Example from planningmap.mdc:

### ArcGIS Services

The PlanningMap component can display layers from the following ArcGIS REST services:

- **Main Services Directory**: [https://gis.sauevald.ee/arcgis/rest/services](mdc:https:/gis.sauevald.ee/arcgis/rest/services)

:laptop: Environment:

  • OS: macOS 24.4.0
  • Cursor Version: Latest (as of April 2025)

:prohibited: Impact:
Medium severity - While not preventing the use of Cursor, this issue:

  • Breaks documentation links
  • Creates invalid URLs
  • Requires manual correction of URLs
  • Affects documentation readability and maintenance

:white_check_mark: Forum Check:
I’ve checked the forum and haven’t found any existing reports of this specific URL modification issue in .mdc files. There is an open question available related to the same issue: What is "mdc:" link schema?

Additional Notes:

  • The issue appears to be consistent across all .mdc files
  • The modification happens automatically upon saving
  • The pattern is consistent: https:// becomes mdc:https:/ (note the missing slash)
  • This appears to be an unintended URL transformation specific to .mdc file handling
2

I added the following rule to my Cursor rules to overcome this bug:

**CRITICAL**: The AI assistant MUST NEVER make documentation changes without full understanding:
1. STOP automatically modifying URL protocols (e.g., changing https:// to mdc:)
2. Only make documentation changes that can be fully explained and justified
3. When in doubt, ask for clarification before suggesting documentation changes