diff --git a/README.md b/README.md
index a5aca8a..cedb502 100644
--- a/README.md
+++ b/README.md
@@ -65,4 +65,13 @@ rec {
 ```
 $ which dotnet
 /nix/store/87s452c8wj2zmy21q8q394f6rzf5y1br-dotnet-sdk-6.0.100/bin/dotnet
-```
\ No newline at end of file
+```
+
+So now we have our development tools (well, tool). The `dotnet --help` text tells us a few things about telemetry, so let's define a prompt so we know when we're in the nix shell and then set the telemetry opt-out.
+
+```
+shellHook = ''
+  PS1="5dplomacy:\W$ "
+'';
+DOTNET_CLI_TELEMETRY_OPTOUT = 1;
+```
diff --git a/flake.nix b/flake.nix
index 2e569ff..85905d5 100644
--- a/flake.nix
+++ b/flake.nix
@@ -8,6 +8,10 @@
       let pkgs = nixpkgs.legacyPackages.${system};
       in rec {
         devShell = pkgs.mkShell {
+          shellHook = ''
+            PS1="5dplomacy:\W$ "
+          '';
+          DOTNET_CLI_TELEMETRY_OPTOUT = 1;
           packages = [ pkgs.dotnet-sdk ];
         };
       }