diff --git a/.gitignore b/.gitignore
index 5f0cf05..a987355 100644
--- a/.gitignore
+++ b/.gitignore
@@ -13,3 +13,6 @@ obj/
 .dotnet/
 .local/
 Library/
+
+## Javascript 
+.node_modules
\ No newline at end of file
diff --git a/AGENTS.md b/AGENTS.md
new file mode 100644
index 0000000..205e77e
--- /dev/null
+++ b/AGENTS.md
@@ -0,0 +1,6 @@
+# Purpose
+This is a C# exercise repository to explore creating class and sequence diagrams with mermaid, in order to understand an unfamiliar codebase, perform continuous architecture review, or review code generated by coding agents.
+
+# Generating mermaid diagrams and reviewing syntax
+
+On linux and mac, the `mmdc` executable is available to create svg diagrams and check syntax. On windows, use the mmdc binary in `./node_modules/bin/mmdc` .
diff --git a/README.md b/README.md
index 2f07b8e..c022ebb 100644
--- a/README.md
+++ b/README.md
@@ -22,6 +22,11 @@ A small C# application for practicing code exploration with a coding agent: use
    ```
    dotnet build
    ```
+4. On windows: npm install @mermaid-js/mermaid-cli (global install failed)
+5. Verify mermaid runs
+   ```
+   ./node-modules/.bin/mmdc
+   ```
 
 ## Tasks
 
diff --git a/package.json b/package.json
new file mode 100644
index 0000000..a820963
--- /dev/null
+++ b/package.json
@@ -0,0 +1,5 @@
+{
+  "devDependencies": {
+    "@mermaid-js/mermaid-cli": "^11.17.0"
+  }
+}
\ No newline at end of file