---
description: >-
  Review earlier versions of a Model, Metric, Glossary term or AI Analyst,
  compare them with the current version, and restore one.
---

# Version history and restore

Every time you save a change to a Model, Metric, Glossary term or AI Analyst (the agent), Studio records a new version with a full snapshot of its definition. You can review those versions, see exactly what changed, and restore an earlier one.

!!! info "Availability"
    - **Who can do this:** members with the **Edit** capability in the active Workspace. Without it, the **Restore** action is hidden.

## What gets versioned

| Item | What a version contains |
| --- | --- |
| Model | The model and all its dimensions, measures, filters, relationships and tags |
| Metric | The metric, including its joins, filters and available sets |
| Glossary term | The term, including its tags, mappings and parent term |
| AI Analyst | Its name, description, instructions, avatar, model and glossary access settings, and Explorer deployment (see [What restoring an AI Analyst brings back](#what-restoring-an-ai-analyst-brings-back)) |

A few things to know:

* For a model, saving a change to one of its dimensions, measures, filters or relationships also creates a new version of the model.
* A save that changes nothing does not create a version.

## Open version history

* **Model, Metric or Glossary term:** open it in Studio and click the history (clock) icon in the top-right corner of the page. Its tooltip is **Version history**.
* **AI Analyst:** open the analyst in Studio and click **Version history** in the page header.

The **Version history** dialog opens.

<!-- screenshot: semantic-layer-version-history-dialog -->

## Read the version list

Versions are listed newest first. Each row shows:

* **Version** and its number, for example "Version 7"
* How long ago it was saved, for example "3 hours ago"
* A one-line summary of the change, when available
* **by** and the name of the person who made the change, when available

The newest row is marked **Current**.

Change summaries are generated automatically when the change is saved:

| Change | Example summary |
| --- | --- |
| First version | "Created model", "Created metric", "Created term", "Created analyst" |
| Rename | "Renamed model to orders_v2" |
| Change to a model's dimension, measure, filter or relationship | "Added dimension region", "Removed measure revenue", "Renamed dimension status → order_status", "Updated filter active_only" |
| Any other change | "Updated metric" |

Restoring a version is summarized the same way as any other change (for example "Updated model"), not as a restore.

## Compare a version with the current one

1. In the version list, hover over an older version. **View changes** and **Restore** appear. They never appear on the **Current** row.
2. Click **View changes**.

The dialog switches to **Compare changes**. The header shows the selected version and the current version (for example "Version 4 → Version 7") with the number of added and removed lines.

The comparison shows both definitions as YAML, line by line:

* Added lines are in the current version.
* Removed lines were in the selected older version.
* Long runs of unchanged lines collapse to "*N* unchanged lines". Click one to expand it.
* Names of other items (for example a model a metric uses) are links. Clicking one closes the dialog and opens that item.

If nothing differs, you see "No changes between these versions."

To return to the list, click the back arrow (**Back to versions**).

<!-- screenshot: semantic-layer-compare-changes -->

## Restore a version

1. In the version list, hover over the version you want and click **Restore**.
2. In **Restore this version?**, click **Restore**.

Restoring doesn't delete history. Studio records a new version that matches the selected one, and the previous current version stays in the list, so you can undo a restore by restoring again.

!!! note "Version restore is not undelete"
    Restoring an earlier version rolls back the content of an item that still exists. It doesn't bring back an item that was deleted.

## What restoring an AI Analyst brings back

An AI Analyst version captures:

* Name, description, instructions and avatar
* Model access: the access mode, chosen models, and any narrowed dimensions and measures or chosen tags
* Glossary access: the access mode and chosen tags
* Whether the analyst is deployed in Explorer, who can see it there, and the users it is shared with

Slack and Microsoft Teams deployments are not part of a version, so restoring doesn't change them.

!!! warning "Restoring can change Explorer deployment"
    Because Explorer deployment is part of the version, restoring an AI Analyst version can deploy or undeploy it in Explorer and change who can see it.

If a model, dimension, measure, tag or user that the version refers to no longer exists, Studio skips that part of the access settings and restores everything else. The restore doesn't fail.

An AI Analyst that was created before version history was available has no versions until you next save a change to it. Until then its history shows "No versions yet."

If the restored version uses **Choose specific models**, the restore can be refused when it would exceed your organization's **Models per AI Analyst** limit.

## Changes made by the Steward

Changes the Steward makes to models, metrics, glossary terms and AI Analysts are recorded as versions too, so you can review and restore them here. Versions created by the Steward may show a system author name in the **by** line instead of a person. You can also roll back Steward changes from the Steward conversation itself, using **Rollback to here** on a message or **Rollback all changes** for the whole conversation.

## Related pages

* [Models](models/README.md)
* [Metrics](metrics.md)
* [Glossary](glossary.md)
* [Tags](tags.md)