diff --git a/constraint/cgo_is_required.go b/constraint/cgo_is_required.go
new file mode 100644
index 0000000..900e837
--- /dev/null
+++ b/constraint/cgo_is_required.go
@@ -0,0 +1,7 @@
+//go:build !cgo
+
+package constraint
+
+func _() {
+	"This package requires cgo to build. An error here means cgo is disabled for your build."
+}
diff --git a/constraint/constraint.go b/constraint/constraint.go
new file mode 100644
index 0000000..a3798fd
--- /dev/null
+++ b/constraint/constraint.go
@@ -0,0 +1,3 @@
+//go:build cgo
+
+package constraint
diff --git a/constraint/go.mod b/constraint/go.mod
new file mode 100644
index 0000000..6f718ba
--- /dev/null
+++ b/constraint/go.mod
@@ -0,0 +1,3 @@
+module git.sunturtle.xyz/zephyr/errors-my-beloved/syntax
+
+go 1.25.0
diff --git a/go.work b/go.work
index ec057f8..098806f 100644
--- a/go.work
+++ b/go.work
@@ -7,4 +7,5 @@ use (
 	./iface
 	./sizeofstring
 	./stringer
+	./constraint
 )