---
title: "How to view the change history of a Fast Line Pro agent and roll back a version"
description: "Who changed the agent settings, when and from where; what changed, comparison with the current version, view with copy, and rollback; who changed knowledge base documents and chunks."
---

# How to view the change history of a Fast Line Pro agent and roll back a version?

The agent editor has a **History** button. It lists every save of the agent settings: **who, when and from where** made it. For each version you can see what changed, compare it with the current agent, view and copy the instructions and variables, and **restore** the version if needed.

<!-- Screenshot: the «History» button in the agent editor and the drawer with versions (added by the demo). -->

## When you need it

- The agent prompt changed and you need to know who changed it and when.
- The agent answers worse after a change and you need the previous instructions or model back.
- You need a piece of an old prompt without rolling the agent back.

## Important to know

- The history is recorded **since the platform update**. Earlier changes do not appear in it.
- Versions are kept for **180 days**, then removed automatically.
- The history works when the settings change log (**Settings Audit Trail**) is enabled on the instance. When it is off, there is no **History** button.
- **Restored:** instructions, variables, model (with its parameters), connected knowledge bases together with their search settings (number of results, threshold, reranking) and image/file upload.
- **Not restored:** agent tools (built-in, MCP, scenario MCP Tool sections) and service settings not shown in the editor. They stay as they are now. Tool changes are visible in the history and in **View**.
- The **source** of a version is for reference:
  - **UI** — a save from the Constructor panel. External integrations that send requests with the `X-CSRF-TOKEN` header are labelled the same way.
  - **API** — a request with a token in the `Authorization: Bearer` header. Instance Agent working without delegation (with a regular login token) is recorded as **API** too.
  - **Instance Agent** — a change Instance Agent made on behalf of a user.
  - **MCP** — a request with an MCP key.
  - **System** — a change without a user: applying a **Marketplace** package, the **AI QA checklist** sync, a **scenario binding**. Such records have no author: “System · AI QA checklist” does not mean the person who saved the checklist.
- Edits made **bypassing the panel** (directly in the agent backend) are not recorded. They appear as part of the next publication and look like a change by whoever published it.
- A version is written right after the publication, in the background. If the platform restarts at that very moment, the record may be lost.
- A rollback publishes the agent **immediately**: it starts answering with the restored version, including in ongoing conversations.

## Before you start

- [x] To see the history — the Fast Line Pro view right (**Fast Line → view**).
- [x] To restore versions — also the save right (**Fast Line → save**).
- [x] The agent is opened in the new Fast Line Pro interface: `Menu → Fast Line Pro → Agents → agent`.

## How to view the history

1. Open the agent: **Fast Line Pro** → **Agents** → the agent.
2. Click **History** next to the agent name.
3. The **Agent settings** tab lists the versions, newest first. Each row shows the date and time, the author and the source. A rollback has the line “Rollback to version from …”.
4. Click **Show more** to load earlier versions (20 at a time).

The oldest record may have the item **State before the first recorded change** — the agent settings as they were before the first save after the platform update.

## What you can do with a version

| Action | What it shows |
|--------|---------------|
| **What changed** | The difference between the state before and after this save. Instructions — line by line, model — “parameter: was → is”, variables, knowledge bases and files — “Before / After”, tools — “Added / Removed / Settings changed”. Unchanged sections are collapsed and marked “No changes”. |
| **Compare with current** | The difference between the version and the agent now. |
| **View** | The whole version, read-only. **Copy** next to the instructions and every variable. |
| **Restore this version** | Roll the agent back to the version (save right only). |

The value `***` is hidden (for example, an access key). It is not compared and does not count as a change.

If the previous state of a version was not recorded (for example, the first save of a new agent), **What changed** shows “The previous state was not recorded” and the version itself.

## How to restore a version

1. In the version row, click **Restore this version**.
2. In the confirmation window, review the difference with the current agent and the warnings:
   - how many changes were made after this version and by whom — they will be overwritten;
   - **Tools are not rolled back** — when the version had a different set of tools;
   - the agent is managed by an AI QA checklist or modified by Instance Agent — they may overwrite the rollback;
   - a knowledge base of the version was deleted or is unavailable — it will not be connected;
   - the model of the version is no longer available — the current one is kept;
   - unsaved changes in the editor will be lost.
3. Click **Restore**.

After the rollback you see “Version restored and published”, the editor reloads the agent, and the history gets a new row “Rollback to version from …”. A rollback can be rolled back too.

## Knowledge base change history

The same **History** window has a second tab — **Knowledge base**. It shows who added, edited, enabled or disabled, or deleted documents and chunks of the knowledge bases **currently connected to the agent**, when and from where.

<!-- Screenshot: the “Knowledge base” tab with the “Chunk edited” and “Chunks uploaded” rows (added by the demo). -->

Each row shows:

- date and time, author and source — the same labels as for agent versions (**UI**, **API**, **Instance Agent**, **MCP**, **System**);
- the action: “Document added”, “Document renamed”, “Document enabled”, “Document disabled”, “Document deleted”, “Chunk added”, “Chunk edited”, “Chunk enabled”, “Chunk disabled”, “Chunk deleted”, “Chunks uploaded: N new, M updated”, “File import: N applied”;
- the knowledge base and the document. Chunks written via API or MCP (for example, by Instance Agent) go to a service document — the row calls it **Chunks from API/MCP**, its technical name is shown in the hover hint;
- up to 5 chunk or document IDs and “and N more”, plus the count.

Important to know:

- **Chunk text is not stored** and is not shown. A chunk or document cannot be restored from the history — you only see who changed what.
- Only knowledge bases **currently connected** to the agent are shown. If you disconnect a knowledge base, its rows disappear from the tab but stay in the [settings change log](/en/settings/how-to/view-settings-audit-log.md) (types **Fastline Pro knowledge base documents** and **Fastline Pro knowledge base chunks**).
- A chunk import from a file is recorded as **one row** “File import: N applied” — without an author, with the **System** source.
- Not recorded: applying a **Marketplace** package and edits made bypassing the panel.
- If enabling chunks ended with an error (for example, a chunk was not indexed), that change may be missing from the history.
- The knowledge base history is also recorded since the platform update and kept for 180 days.

### Where else to look

All changes of one knowledge base are also shown on the page of the knowledge base itself: **Knowledge bases** → the knowledge base you need → the **History** button above the document list. The **Knowledge base change history** window shows the same rows as the agent tab, but for the whole knowledge base — including when it is not connected to any agent or was disconnected. There is no filter by document here.

<!-- Screenshot: the “Knowledge base change history” window on the knowledge base page (added by the demo). -->

## How to check that it works

- Change a line in the instructions and click **Publish** → **History** shows a new top row with your name and the **UI** source.
- **What changed** for that row shows only the changed instruction line, the other sections are “No changes”.
- The [settings change log](/en/settings/how-to/view-settings-audit-log.md) has a **Fast Line Pro agent settings** record with the link “See the agent history for details”.
- Edit a chunk of a connected knowledge base → **History** → **Knowledge base**: the top row is “Chunk edited” with your name, the **UI** source, the chunk ID and “1 chunk”.

## Common situations

| Situation | What to do |
|-----------|------------|
| “The agent was changed while you were viewing it” | Someone published the agent while the rollback window was open. Click **Refresh**, review the difference again and repeat the rollback. |
| “Version not found” | The version is older than 180 days and was removed. |
| “This version cannot be restored automatically” | The version has a hidden value the agent no longer has. Copy the parts you need via **View** and enter them manually. |
| “Could not publish the agent” | Try again later; the agent was not changed. |
| No **History** button | The settings change log is off on the instance, or you have no Fast Line Pro view right. |
| No **Restore this version** button | You have no Fast Line Pro save right. |

## Related materials

- [Configure the agent prompt](/en/fastlinepro/how-to/configure-agent-prompt.md)
- [Connect and configure agent tools](/en/fastlinepro/how-to/configure-agent-tools.md)
- [Connect a knowledge base to the agent](/en/fastlinepro/how-to/connect-knowledge-base-to-agent.md)
- [View the settings change log](/en/settings/how-to/view-settings-audit-log.md)