diff --git a/src/lib/node.js b/src/lib/node.js
index cff27fa..17e46b6 100644
--- a/src/lib/node.js
+++ b/src/lib/node.js
@@ -184,4 +184,6 @@ function negate(node) {
   return { type: 'Sum', terms: [{ sign: -1, node }] };
 }
 
+// Stryker disable next-line all: instrumenting this line breaks Node's
+// cjs-module-lexer named-export detection for .mjs `import { x } from` consumers.
 module.exports = { num, dim, ident, call, mkSum, mkProduct, negate };
diff --git a/src/lib/serialize.js b/src/lib/serialize.js
index ec1035c..8e4844f 100644
--- a/src/lib/serialize.js
+++ b/src/lib/serialize.js
@@ -221,4 +221,6 @@ function serializeProduct(product, prec) {
   return out;
 }
 
+// Stryker disable next-line all: instrumenting this line breaks Node's
+// cjs-module-lexer named-export detection for .mjs `import { x } from` consumers.
 module.exports = { serialize };
diff --git a/src/lib/simplify.js b/src/lib/simplify.js
index 9558c6c..c4f89dc 100644
--- a/src/lib/simplify.js
+++ b/src/lib/simplify.js
@@ -35,4 +35,6 @@ function simplify(node) {
   }
 }
 
+// Stryker disable next-line all: instrumenting this line breaks Node's
+// cjs-module-lexer named-export detection for .mjs `import { x } from` consumers.
 module.exports = { simplify };