diff --git a/Home.md b/Home.md
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+++ b/Home.md
@@ -14,6 +14,7 @@ what it is and how to install it is in the
 | [Building](Building) | Requirements, building and running from source — including the mpv piece, without which the app is a downloader rather than a player. |
 | [Tracking-upstream](Tracking-upstream) | How the fork relates to YTSage, and how a merge from upstream is done. |
 | [Upstream-README](Upstream-README) | YTSage's own README, kept verbatim for reference. |
+| [Working-notes](Working-notes) | The rules to know before touching the fork, in one place. |
 
 ## This repository is a fork, and it is treated as one
 
diff --git a/Working-notes.md b/Working-notes.md
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@@ -0,0 +1,14 @@
+# Working notes
+
+The rules to know before touching the fork, in one place. Added 2026-10-02 so every
+wiki in the org has this page. [Tracking-upstream](Tracking-upstream) is the long form.
+
+1. **The history is never rewritten.** SageTube still merges from `oop7/YTSage`, and a
+   rewrite would change every commit id and break the next merge.
+2. **Tags up to `v5.3.0b` are upstream's**, inherited with the history. SageTube's own
+   versions continue that line (`v5.5.x`); the version lives in `pyproject.toml`.
+3. **`upstream` is a real remote pointing at GitHub. Never push to it.**
+4. **`.github/` and `readme-translations/` are upstream's files.** Leave them where
+   upstream put them, or the next merge conflicts.
+5. The **mpv** piece is what makes it a player rather than a downloader — see
+   [Building](Building) before declaring a build working.