diff --git a/.markdownlint-cli2.jsonc b/.markdownlint-cli2.jsonc
index 80b13ad117c..3401ad31a87 100644
--- a/.markdownlint-cli2.jsonc
+++ b/.markdownlint-cli2.jsonc
@@ -32,6 +32,7 @@
     "target/**",
     "**/_temp/**",
     "**/_ai/**",
+    "**/.cursor/plans/**",
     "libs/@hashintel/ds-components/**",
     "libs/@hashintel/ds-helpers/**"
   ]
diff --git a/libs/@blockprotocol/type-system/rust/README.md b/libs/@blockprotocol/type-system/rust/README.md
index 54d680ddfc1..eaedd038e97 100644
--- a/libs/@blockprotocol/type-system/rust/README.md
+++ b/libs/@blockprotocol/type-system/rust/README.md
@@ -1,9 +1,13 @@
-# Block Protocol Type System
+# SemType (Block Protocol Type System)
 
-This crate implements the Block Protocol type system in Rust. It provides the foundation for defining, validating, and working with typed data in the HASH ecosystem. For details on the type system design, see the [Block Protocol Type System RFC](https://github.com/blockprotocol/blockprotocol/blob/main/rfcs/text/0352-graph-type-system.md).
+This crate implements the SemType specification in Rust. It provides the foundation for defining, validating, and working with typed data in the HASH ecosystem.
+
+**The public, canonical specification of the type system is published at [semtype.org/spec](https://semtype.org/spec).** This Rust crate is the reference implementation; the spec is kept in sync with it by hand, so changes to the type system here should be reflected at `semtype.org/spec`.
 
 The corresponding TypeScript implementation can be found in the [`@blockprotocol/type-system`](../typescript) package. This crate is used to generate the TypeScript typings from the Rust implementation.
 
+The predecessor to SemType was the "Block Protocol type system". For details on its (now deprecated) design, see the original [Block Protocol Type System RFC](https://github.com/blockprotocol/blockprotocol/blob/main/rfcs/text/0352-graph-type-system.md).
+
 ## Overview
 
 The Block Protocol Type System defines a structured approach to typing data. It enables: