# Write-back

> Edit the semantic model from the UI and open a governed GitHub pull request instead of mutating production directly

*[View this page in the Flax docs](https://flax-analytics.com/docs/modeling/write-back)*

Write-back lets you edit the semantic model from the Flax UI without hand-editing YAML — while keeping every change governed. Instead of silently mutating production, an edit becomes a **changeset** that opens a **GitHub pull request** for review. This page is for modelers and admins who want to edit the model safely.

## Governed edits, not silent mutations

The semantic model is git-backed, so a UI edit is a code change. When you change a dimension, measure, join, or description in the UI, Flax:

1. Captures your edits as a **changeset** against the model files in your connected repository.
2. Opens a **pull request** on GitHub with the resulting YAML diff.
3. Lets your team review, comment, and merge through the normal git workflow.

Nothing reaches the live model until the pull request merges. This preserves review, version history, and auditability — the same governance you'd get from editing the files by hand, without leaving Flax.

## What you need

Write-back is built on the [GitHub App](/docs/developers/github-app) and a connected [dbt project](/docs/connections/dbt-projects):

- The GitHub App must be installed and authorized to open pull requests on the repository holding your model YAML.
- A dbt project connection tells Flax which repository and files hold the semantic model.

> [!IMPORTANT]
> Write-back requires the GitHub App connection and write access to the target repository. Without it, the model is read-only from the UI and you edit the YAML directly in git.

## How it flows

Under the hood, Flax stages the edit, generates the YAML diff, and creates the pull request through the GitHub App. Once the changeset is created it is tracked as an open pull request you can follow to merge. Because the output is an ordinary PR, your existing branch protections, required reviewers, and CI checks all apply.

## Related

- [GitHub App](/docs/developers/github-app) — install and authorize write-back.
- [dbt projects](/docs/connections/dbt-projects) — connect the repository holding your model.
- [Modeling overview](/docs/modeling/overview).
- [Semantic YAML reference](/docs/modeling/semantic-yaml-reference).