diff --git a/devenv.nix b/devenv.nix
index 92ab5bd..422269e 100644
--- a/devenv.nix
+++ b/devenv.nix
@@ -33,6 +33,7 @@
 
   enterShell = ''
     export PATH=$HOME/.cargo/bin:$PWD/src/bin:$PWD/node_modules/.bin:$PATH
+    cargo install mdbook-cmdrun
 
     if [[ -n "$DEVENV_NIX" ]]
     then