diff --git a/.gitmodules b/.gitmodules
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+++ b/.gitmodules
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+[submodule "ruff"]
+	path = ruff
+	url = https://github.com/astral-sh/ruff
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
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+# Contributing
+
+## Repository structure
+
+ty's Rust crates can be found in the [Ruff](https://github.com/astral-sh/ruff) project. While the
+relationship between these projects will evolve over time, they currently share foundational crates
+and it's easiest to use a single repository for development. To contribute changes to ty's core,
+open a pull request on the Ruff repository.
+
+The Ruff repository is included as a submodule to allow ty's release tags to reflect an exact
+snapshot of the Ruff project. The submodule is only updated on release. To see the latest
+development code, visit the Ruff repository.
+
+The ty repository only includes code relevant to distributing the ty project.
+
+## Getting started with the ty repository
+
+Clone the repository:
+
+```
+git clone https://github.com/astral-sh/ty.git
+```
+
+Then, ensure the submodule is initialized:
+
+```
+git submodule update --init --recursive
+```
diff --git a/ruff b/ruff
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+++ b/ruff
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+Subproject commit 675a5af89af5b786a6c99870fe0cf7f841454271