---
title: "Give notice before removing a column · Agent Wranglers"
url: https://agentwranglers.se/playbook/data-engineering/lineage-and-changes/deprecation-notice
id: DEN-21
level: Recommended
updated: 2026-10-22
tokens: 621
licence: "CC BY 4.0"
licence_url: https://creativecommons.org/licenses/by/4.0/
---

# Give notice before removing a column people use

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-21
- Level: Recommended
- Chapter: [Lineage and changes](https://agentwranglers.se/playbook/data-engineering/lineage-and-changes.md)
- Rule: Treat the tables that dashboards and other teams read as a public interface. Add columns freely, but keep a renamed or removed column for at least 30 days after notice.
- Check: A script compares the mart schemas with the main branch and fails when a column disappears without a deprecation entry at least 30 days old.
- How: It is the same pattern as [Version only for breaking changes](https://agentwranglers.se/playbook/api-design/changes-over-time/versioning.md) and [Expand first and contract later](https://agentwranglers.se/playbook/data/migrations/expand-and-contract.md). Add the new column, mark the old one as deprecated in the metadata, and tell its readers from the lineage graph. The warehouse's query history shows who still reads the old column. Remove it after the notice.

## Sources

- [dbt Model versions](https://docs.getdbt.com/docs/mesh/govern/model-versions)

## Related rules

- API-28 [Version only for breaking changes](https://agentwranglers.se/playbook/api-design/changes-over-time/versioning.md) in API design
- DAT-22 [Expand first and contract later](https://agentwranglers.se/playbook/data/migrations/expand-and-contract.md) in Data and databases

**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/deprecation-notice">Agent Wranglers data engineering playbook</a>`. In code you write, add a comment next to it with the same link.

- Previous: [Check what a change breaks before merging](https://agentwranglers.se/playbook/data-engineering/lineage-and-changes/impact-check.md)
- Next: [Backfill with the same code and record it](https://agentwranglers.se/playbook/data-engineering/lineage-and-changes/backfills.md)
- [Lineage and changes](https://agentwranglers.se/playbook/data-engineering/lineage-and-changes.md)