Edit a model in a draft version

Published and approved versions cannot be changed. Every change starts in a new draft version, which is a copy of the live model. This keeps a clear record of what changed and who approved it.

Create a draft version

Open the project and click New Version. Ptally copies the latest live model into a new draft and opens it. If a draft already exists, the button reads View Draft Version instead, so you continue working on that draft.

Describe the change

At the top of the draft, What changed shows the draft's history. Write a short summary in the box beside it, for example "Greater London vet fee inflation: region factor 1.30 to 1.35", and click Save summary. Reviewers see this before they approve.

Edit a step

In a draft, each step in the steps list has an edit icon. Click a step to open it in edit mode. For a collection step you can:

• edit values in the rate table directly;
• Upload CSV or Paste CSV to replace the table;
• Download CSV to work on the table in a spreadsheet;
• add output fields and change their expressions.

Click Save step to keep your changes, or Cancel to discard them.

Upload a whole model

For larger changes, use Upload model above the model JSON to replace the draft's model with a JSON file. A common route is to click Download JSON, make the changes, then upload the edited file.

Check the change

After editing:

1. Click Run all tests and compare the results with the expected values.
2. Use Quote Dry Run to try a few quotes against the draft.
3. Update the expected result of any test the change was meant to affect, and be able to explain why.

When you are happy with the draft, it is ready for approval. See Approve and publish a version.

Editing with an AI client

AI clients connected over MCP can read a draft and apply targeted changes with the patch_version tool, then run the tests. They can only change drafts. Approving and publishing stays with you.