diff --git a/macOS.yaml b/macOS.yaml
index 09d022e..4f37f28 100644
--- a/macOS.yaml
+++ b/macOS.yaml
@@ -8,3 +8,4 @@
     - role: iterm
     - role: magnet
     - role: obsidian
+    - role: viscosity
diff --git a/roles/viscosity/tasks/main.yaml b/roles/viscosity/tasks/main.yaml
new file mode 100644
index 0000000..464724d
--- /dev/null
+++ b/roles/viscosity/tasks/main.yaml
@@ -0,0 +1,8 @@
+---
+- assert:
+    that: ansible_os_family == "Darwin"
+
+- name: install homebrew package
+  homebrew_cask:
+    name: viscosity
+    state: latest