<!--IssueSummary start--> <details> <summary> Everyone can contribute. [Help move this issue forward](https://handbook.gitlab.com/handbook/marketing/developer-relations/contributor-success/community-contributors-workflows/#contributor-links) while earning points, leveling up and collecting rewards. </summary> - [Close this issue](https://contributors.gitlab.com/manage-issue?action=close&projectId=278964&issueIid=561089) </details> <!--IssueSummary end--> ### Proposal Improve fork error messages when instance runners cause failures. #### Current State Fork failures return generic "409 Conflict" error without letting users know instance runner config are the problem #### Problem Statement When forking fails due to instance runner configuration, the error message doesn't explain why or how to fix it #### Proposed Solution Add details to the error when this occurs: - Show: "Fork failed due to conflicting instance runners configuration. Try temporarily disabling runners on the source project." #### Technical Details - **API endpoint**: `POST /api/v4/projects/{id}/fork` - **Current error**: HTTP 409 with no helpful details #### Benefits 1. Users can fix the issue themselves #### Acceptance Criteria - [ ] Fork API detects runner configuration issues - [ ] Error message explains the problem and solution