Problem

When using apply_suggestion or apply_suggestions actions in manage_mr_discussion tool, GitLab returns 404 errors even when the suggestion exists.

Error example:

{
  "error_code": "NOT_FOUND",
  "tool": "manage_mr_discussion",
  "action": "apply_suggestion",
  "http_status": 404,
  "message": "Resource not found or you don't have access to it"
}

Root Cause

We were using incorrect nested endpoints:

• PUT /projects/:id/merge_requests/:iid/suggestions/:sid/apply
• PUT /projects/:id/merge_requests/:iid/suggestions/batch_apply

But GitLab Suggestions API uses global endpoints:

• PUT /suggestions/:id/apply
• PUT /suggestions/batch_apply

Suggestion IDs are globally unique and don't require project/MR context in the URL.

Solution

Update the handler in src/entities/mrs/registry.ts to use the correct global endpoints.

References

• GitLab Suggestions API Documentation
• Reference implementation: gitlab-review-mcp