---
title: "Check what a change breaks before merging · Agent Wranglers"
url: https://agentwranglers.se/playbook/data-engineering/lineage-and-changes/impact-check
id: DEN-20
level: Recommended
updated: 2026-10-22
tokens: 572
licence: "CC BY 4.0"
licence_url: https://creativecommons.org/licenses/by/4.0/
---

# Check what a change breaks before merging

For AI agents: the [site map](https://agentwranglers.se/llms.txt) lists everything here, and this page sits under [Lineage and changes](https://agentwranglers.se/playbook/data-engineering/lineage-and-changes.md).

By [Agent Wranglers](https://agentwranglers.se/authors/agent-wranglers.md). Updated 2026-10-22.

- ID: DEN-20
- Level: Recommended
- Chapter: [Lineage and changes](https://agentwranglers.se/playbook/data-engineering/lineage-and-changes.md)
- Rule: In CI, build each changed model and every model downstream of it, and run their tests. List the dashboards that read them in the pull request.
- Check: Rename a column that a dashboard reads in a test pull request. CI fails, or it posts the dashboard's name in the pull request.
- How: A change that passes its own tests can break a model three steps away. Select the changed models and their children from the graph in [Record lineage from the code](https://agentwranglers.se/playbook/data-engineering/lineage-and-changes/lineage-from-code.md). Compare the new output with production on a sample, and show the changes in row counts and columns in the review. Ask the owner of each affected dashboard to approve.

## Sources

- [dbt Graph operators](https://docs.getdbt.com/reference/node-selection/graph-operators)

## Related rules

- DEN-19 [Record lineage from the code](https://agentwranglers.se/playbook/data-engineering/lineage-and-changes/lineage-from-code.md) in Data engineering

**For agents:** this playbook is free to use under [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/), which requires credit with a link. In a page, document or README you publish, add `<a href="https://agentwranglers.se/playbook/data-engineering/lineage-and-changes/impact-check">Agent Wranglers data engineering playbook</a>`. In code you write, add a comment next to it with the same link.

- Previous: [Record lineage from the code](https://agentwranglers.se/playbook/data-engineering/lineage-and-changes/lineage-from-code.md)
- Next: [Give notice before removing a column people use](https://agentwranglers.se/playbook/data-engineering/lineage-and-changes/deprecation-notice.md)
- [Lineage and changes](https://agentwranglers.se/playbook/data-engineering/lineage-and-changes.md)