diff --git a/doc/manual/rl-next/deprecate-build-hook.md b/doc/manual/rl-next/deprecate-build-hook.md
new file mode 100644
index 000000000..30de1298d
--- /dev/null
+++ b/doc/manual/rl-next/deprecate-build-hook.md
@@ -0,0 +1,8 @@
+---
+synopsis: "The `build-hook` setting is now deprecated"
+category: Breaking Changes
+---
+
+Build hooks communicate with the daemon using a custom, internal, undocumented protocol that is entirely unversioned and cannot be changed.
+Since we intend to change it anyway we must unfortunately deprecate the current build hook infrastructure.
+We do not expect this to impact most users—we have not found any uses of `build-hook` in the wild—but if this does affect you, we'd like to hear from you!
diff --git a/src/libstore/globals.hh b/src/libstore/globals.hh
index 1aeb462d4..4709ac715 100644
--- a/src/libstore/globals.hh
+++ b/src/libstore/globals.hh
@@ -248,14 +248,18 @@ public:
         )",
         {"build-timeout"}};
 
-    Setting<Strings> buildHook{this, {}, "build-hook",
+    Setting<Strings> buildHook{
+        AbstractSetting::deprecated_t{},
+        this, {}, "build-hook",
         R"(
           The path to the helper program that executes remote builds.
 
           Lix communicates with the build hook over `stdio` using a custom protocol to request builds that cannot be performed directly by the Nix daemon.
           The default value is the internal Lix binary that implements remote building.
 
-          > **Important**
+          > **Warning**
+          >
+          > This setting is deprecated and will be removed in a future version of Lix.
           >
           > Change this setting only if you really know what you’re doing.
         )"};