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# Code tools: see what changed and restore an earlier version

Each save of a code tool now creates a numbered version. You can compare two versions and restore an earlier one from the code tool's page.

## What's new

Open a code tool, open its menu, and select **Version history**.

* **Every save is recorded.** A version is created when the tool changes in the dashboard, over the Platform API, or when a change set promotes it. A test run does not create a version. Ada keeps the newest 25 versions of each tool.
* **Compare two versions.** Select a **Version** and a version to **Compare with**. The **Changes** tab shows each changed field, including the code, inputs, outputs and Availability rules. The **Full version** tab shows the whole tool as it was, read-only.
* **Restore a version.** Select **Restore version N**. Before anything changes, a confirmation shows what the restore changes in the current version. The restore brings back the version's code, inputs, outputs, Availability rules and **Block in simulations** setting. It keeps the current environment and **Active** setting. The restore itself is saved as a new version, so you can undo it.

Secret values in a version are masked. Restore is not available while the tool has unsaved changes.

## Who this affects

Every AI Agent that uses code tools. An existing tool starts its history at its first save after this release. That save also keeps the tool's earlier state as version 1.

Learn more about [comparing and restoring versions](/docs/automation/tools/code-tools/create-a-code-tool#compare-and-restore-versions).