Replay, versions and rollback

Change is where agents break

Most agent failures follow a change: a tweaked instruction, an extra tool, a different model. Two practices make change safe: you can compare the new behaviour with the old on real inputs, and you can go back.

Versions

A version is a saved snapshot of the agent's configuration. Every save that changes instructions, tools, schedule, model, approvals, budgets or guardrails is kept as a new version, and runs record which version they used. That gives you history and the ability to ask "which change caused this?"

Replay

Replay takes a past run's input and runs it again against the agent's current version, in test mode, so nothing is sent or changed. You then see the new answer next to the original. It is the fastest way to answer "did my change make this better or worse on real data?"

Rollback

If a new version is worse, restore an older one. A restore does not erase history: it saves the old settings as a new version, so nothing is lost and you can change your mind again.

A safe change routine

1. Make the change in the editor but do not save yet.
2. Open Tests and run your cases with Test my unsaved edits ticked.
3. Save only if they pass.
4. Replay two or three real past runs and compare.
5. If something looks wrong later, restore the previous version.

Steps in PGB Agents

• Versions tab. The tab name shows the current version number. Each entry lists what changed. Choose Restore this version, then confirm. It saves the old settings as a new version.
• Replay. Open a finished run and choose Replay. The new run opens with the badge Replay, the version it used, and a section titled Replay compared with the original showing both answers, their versions, cost and steps.
• Test and replay runs are marked as such and left out of reports, so they do not distort your numbers, though their cost is counted.

Try it yourself

1. Open an agent with a few runs. Edit its instructions in a way that should improve the answer, and save.
2. Open an older run and choose Replay. Compare the original and the replay.
3. Open Versions, find the version before your edit, and choose Restore this version. Check that a new version appears and the instructions are back.

Recap

• Versions record every meaningful change and which version each run used.
• Replay re-runs a past input in test mode against the current version so you can compare.
• Restore returns to earlier settings as a new version, so nothing is lost.