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Simulations

Version history, undo and restoring a version

Every save and publish keeps a snapshot of a simulation, so you can undo edits in the editor or restore an earlier version.

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The simulation editor gives you two ways to step back. Undo and Redo reverse edits you have made since you opened the editor. Version history keeps a snapshot each time the simulation is saved or published, and lets you restore any of them. Both are available on all plans.

Before you start

  • Open the simulation from Studio. The Undo, Redo and Version history buttons are icons at the top of the editor, next to the simulation's name and status.
  • Version history only contains saved states. Edits you have not saved yet are not in it, and restoring a version discards them.

When a version is saved

  • A new simulation gets its first version when it is created.
  • Each time you save with Save Changes, a version is recorded. Moving a simulation to another folder does not record one.
  • Each time you publish, a version is recorded. Unpublishing a published simulation records one too, labeled Unpublished, so the history shows when learners lost access.
  • Each restore is recorded as a version of its own.

Saves made by the same person within 10 minutes of each other are merged into one version, which holds the most recent of those saves. This keeps a run of small edits from filling the history. Published, unpublished and restored versions are never merged, and a change made by an AI tool over MCP always gets its own version.

devlin.ai keeps the most recent 30 versions of each simulation. Older versions are removed as new ones are added.

Steps

  1. In the simulation editor, select the Version history button.
  2. Review the list. Versions are listed newest first, and each one shows a badge (Saved, Published, Unpublished or Restored), when it was made, and the email of the person who made it when that person is a member of the workspace. The top row is the current state and has no restore button.
  3. Select Restore on the version you want.
  4. In the Restore this version? dialog, select Restore to confirm. If you have unsaved edits, the dialog warns that they will be discarded.

Result

The editor shows Version restored and reloads the simulation with the restored content. The restore appears at the top of the list with the Restored badge. The state you had saved before the restore stays in the history, so you can restore back to it.

What a restore changes

A restore sets the simulation's content and settings back to the snapshot: its name, the learner's role, the character, the scenario, behavior triggers, the opening line, end conditions and the turn limit, evaluation settings, variables, feedback settings, the start screen, appearance (colors, sizing, loading screen and branding), voice settings, language, and publishing channels.

A restore does not change:

  • Whether the simulation is published. A published simulation stays published and a draft stays a draft.
  • The embed key, so existing embed codes and links keep working.
  • The folder the simulation is in.
  • The character portrait.
  • Settings that are not part of a snapshot, such as the daily credit cap.
  • Learner conversations and results that were already recorded.

When you restore a version of a published simulation, learners get the restored content right away. If the restored content differs from what was last reviewed, it is screened by content moderation first, and a restore that fails the screening is rejected with the reason shown in the version history dialog.

Undo and redo in the editor

Undo and Redo step through the edits you have made since the editor loaded, across all of its sections. They only change what is in the editor: an undone edit still has to be saved with Save Changes, like any other edit.

  • Keyboard: Cmd+Z (Ctrl+Z on Windows) to undo, and Shift+Cmd+Z (Ctrl+Shift+Z) to redo.
  • While the cursor is in a text field, the keyboard shortcut uses the browser's own undo for that field. Use the Undo and Redo buttons to step through the editor's history instead.
  • A quick burst of edits, such as typing or dragging a slider, counts as one step.
  • If an undo or redo changes a section you are not looking at, a notice names the section and offers Go to section.
  • Making a new edit after an undo clears the steps you could have redone.
  • The editor's history holds up to 50 states, including the current one. The history is not saved anywhere, so it starts empty each time the editor loads.

Coaches

The coach editor has the same Undo, Redo and Version history buttons. Coach versions are recorded, merged, limited and restored in the same way, and a restore leaves the coach's publish state and embed key as they are. Taking a published coach offline, by unpublishing or archiving it, also records a version labeled Unpublished.

AI tools over MCP

An AI tool connected through the MCP server can work with the same history:

  • List versions. With list_versions, a tool can read the version history of a simulation or coach: each version's id, label, and when it was made, newest first.
  • Restore a version. With restore_version, a tool can roll a simulation or coach back to a version from that list, or to the version just before the current one when it names no version. A draft is restored immediately. For a published or archived simulation or coach, the tool has to confirm the live change explicitly, and if the workspace requires in-app approval for live changes, the restore is recorded as a change request for an owner or admin to approve in the app. A tool can also ask for a preview that shows which version and fields would be restored without changing anything.