diff --git a/src/chapters/examples/noop-hello-example/.gitignore b/src/chapters/examples/noop-hello-example/.gitignore
new file mode 100644
index 0000000..d163863
--- /dev/null
+++ b/src/chapters/examples/noop-hello-example/.gitignore
@@ -0,0 +1 @@
+build/
\ No newline at end of file
diff --git a/src/chapters/examples/noop-hello-example/main.cpp b/src/chapters/examples/noop-hello-example/main.cpp
index 7e704e0..c9ce15c 100644
--- a/src/chapters/examples/noop-hello-example/main.cpp
+++ b/src/chapters/examples/noop-hello-example/main.cpp
@@ -9,6 +9,8 @@
 #include <rlbox/rlbox.hpp>
 #include <rlbox/rlbox_noop_sandbox.hpp>
 
+#define release_assert(cond, msg) if (!(cond)) { fputs(msg, stderr); abort(); }
+
 #include "mylib.h"
 
 using namespace std;
@@ -33,9 +35,6 @@ int main(int argc, char const *argv[]) {
 
 // ANCHOR: add
   // call the add function and check the result:
-  auto val = sandbox.invoke_sandbox_function(add, 3, 4);
-  printf("Adding... 3+4 = %d\n", val);
-
   auto ok = sandbox.invoke_sandbox_function(add, 3, 4)
                    .copy_and_verify([](unsigned ret){
     printf("Adding... 3+4 = %d\n", ret);
@@ -76,7 +75,7 @@ int main(int argc, char const *argv[]) {
 void hello_cb(rlbox_sandbox_mylib& _, tainted_mylib<const char*> str) {
   auto checked_string =
     str.copy_and_verify_string([](unique_ptr<char[]> val) {
-        assert(val != nullptr && strlen(val.get()) < 1024);
+        release_assert(val != nullptr && strlen(val.get()) < 1024, "val is null or greater than 1024\n");
         return move(val);
     });
   printf("hello_cb: %s\n", checked_string.get());
diff --git a/src/chapters/examples/wasm-hello-example/.gitignore b/src/chapters/examples/wasm-hello-example/.gitignore
new file mode 100644
index 0000000..1c6adc6
--- /dev/null
+++ b/src/chapters/examples/wasm-hello-example/.gitignore
@@ -0,0 +1,3 @@
+myapp
+mylib.wasm*
+wasm*
\ No newline at end of file
diff --git a/src/chapters/examples/wasm-hello-example/main.cpp b/src/chapters/examples/wasm-hello-example/main.cpp
index 8d8abd4..43f46ac 100644
--- a/src/chapters/examples/wasm-hello-example/main.cpp
+++ b/src/chapters/examples/wasm-hello-example/main.cpp
@@ -15,6 +15,7 @@
 #include "rlbox.hpp"
 #include "rlbox_wasm2c_sandbox.hpp"
 
+#define release_assert(cond, msg) if (!(cond)) { fputs(msg, stderr); abort(); }
 
 using namespace std;
 using namespace rlbox;
@@ -78,7 +79,7 @@ int main(int argc, char const *argv[]) {
 void hello_cb(rlbox_sandbox_mylib& _, tainted_mylib<const char*> str) {
   auto checked_string =
     str.copy_and_verify_string([](unique_ptr<char[]> val) {
-        assert(val != nullptr && strlen(val.get()) < 1024);
+        release_assert(val != nullptr && strlen(val.get()) < 1024);
         return move(val);
     });
   printf("hello_cb: %s\n", checked_string.get());
diff --git a/src/chapters/noop-sandbox.md b/src/chapters/noop-sandbox.md
index 843156a..6a9c02c 100644
--- a/src/chapters/noop-sandbox.md
+++ b/src/chapters/noop-sandbox.md
@@ -167,7 +167,7 @@ string we need to verify it. To do this, we use the string verification function
 
 ```cpp
     str.copy_and_verify_string([](unique_ptr<char[]> val) {
-        assert(val != nullptr && strlen(val.get()) < 1024);
+        release_assert(val != nullptr && strlen(val.get()) < 1024, "val is null or greater than 1024\n");
         return move(val);
     });
 ```