Prompt the editor when a slug already exists in the blog

[valvesa]

There is an issue with detecting that the same slug already exists and not prompting the editor in the UI of the error.
Instead, EmDash is simply not creating the blog draft.

There is no warning/prompt/notification as to WHY it does not create the blog draft when SAVE is clicked.

Successful implementation needs to show the user that the desired slug URL is already in use.

[CacheMeOwside]

Hi @valvesa 👋

Thanks for taking the time to write this up!

This feature has since shipped in 0.33.0 (11 Aug 2026). A rejected save due to an already in-use slug now surfaces a "Failed to save" message instead of failing silently.

Here's a video of how the error shows up:

Screen.Recording.2026-08-14.at.2.31.28.AM.mov

In case you'd like to take a look at the PR that fixed this, here's the link.

Please feel free to upgrade to 0.33.0 or test it out in the EmDash playground and let me know if you continue seeing any issues.

[valvesa]

Thank you! This does work for "pages" but does not work for "posts" type. I just tested on the EmDash playground and when I click "Save" for a slug that already exists (notes-on-simplicity) I get no warning, I only get the warning when I try to PUBLISH. This should work for all post types: pages, posts, tags, bylines (authors) etc, so it warns the editor for any of them, if that slug is already in use.