diff --git a/packages/core/repl.mjs b/packages/core/repl.mjs
index 47231af4d..23c5b25e0 100644
--- a/packages/core/repl.mjs
+++ b/packages/core/repl.mjs
@@ -85,7 +85,17 @@ export function repl({
   const start = () => scheduler.start();
   const pause = () => scheduler.pause();
   const toggle = () => scheduler.toggle();
-  const setCps = (cps) => scheduler.setCps(cps);
+  const setCps = (cps) => {
+    scheduler.setCps(unpure(cps));
+    return silence;
+  };
+
+  function unpure(pat) {
+    if (pat._Pattern) {
+      return pat.__pure;
+    }
+    return pat;
+  }
 
   /**
    * Changes the global tempo to the given cycles per minute
@@ -97,7 +107,10 @@ export function repl({
    * setcpm(140/4) // =140 bpm in 4/4
    * $: s("bd*4,[- sd]*2").bank('tr707')
    */
-  const setCpm = (cpm) => scheduler.setCps(cpm / 60);
+  const setCpm = (cpm) => {
+    scheduler.setCps(unpure(cpm) / 60);
+    return silence;
+  };
 
   // TODO - not documented as jsdoc examples as the test framework doesn't simulate enough context for `each` and `all`..
 
diff --git a/packages/mondough/mondough.mjs b/packages/mondough/mondough.mjs
index 669183279..b7ee83787 100644
--- a/packages/mondough/mondough.mjs
+++ b/packages/mondough/mondough.mjs
@@ -85,7 +85,7 @@ function evaluator(node, scope) {
   let pat;
   if (type === 'plain' && typeof variable !== 'undefined') {
     // some function names are not patternable, so we skip reification here
-    if (['!', 'extend', '@', 'expand', 'square', 'angle', 'all'].includes(value)) {
+    if (['!', 'extend', '@', 'expand', 'square', 'angle', 'all', 'setcpm', 'setcps'].includes(value)) {
       return variable;
     }
     pat = reify(variable);