diff --git a/README.md b/README.md
index c1884cd..293dc7c 100644
--- a/README.md
+++ b/README.md
@@ -2,6 +2,10 @@
 
 This repository contains CLI tooling for composing per-project `AGENTS.md` files from modular rule sets.
 
+## Compatibility
+
+- Node.js >= 20
+
 ## Release notes
 
 See `CHANGELOG.md` for release notes.
@@ -147,11 +151,14 @@ npm install
 npm run lint
 npm run build
 npm test
-```
-
-## Overview
-This repository contains the compose-agentsmd project.
-
-## Requirements and Configuration
-- No required environment variables are documented.
-
+```
+
+## Overview
+This repository contains the compose-agentsmd project.
+
+## Documentation
+- [CHANGELOG.md](CHANGELOG.md)
+- [CONTRIBUTING.md](CONTRIBUTING.md)
+- [SECURITY.md](SECURITY.md)
+- [LICENSE](LICENSE)
+- [CODE_OF_CONDUCT.md](CODE_OF_CONDUCT.md)
diff --git a/package-lock.json b/package-lock.json
index 3a73f61..3ec307a 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -16,6 +16,7 @@
         "compose-agentsmd": "dist/compose-agents.js"
       },
       "devDependencies": {
+        "@types/diff": "^7.0.2",
         "@types/node": "^25.1.0",
         "typescript": "^5.7.3"
       },
@@ -23,6 +24,13 @@
         "node": ">=20"
       }
     },
+    "node_modules/@types/diff": {
+      "version": "7.0.2",
+      "resolved": "https://registry.npmjs.org/@types/diff/-/diff-7.0.2.tgz",
+      "integrity": "sha512-JSWRMozjFKsGlEjiiKajUjIJVKuKdE3oVy2DNtK+fUo8q82nhFZ2CPQwicAIkXrofahDXrWJ7mjelvZphMS98Q==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/@types/node": {
       "version": "25.1.0",
       "resolved": "https://registry.npmjs.org/@types/node/-/node-25.1.0.tgz",
diff --git a/package.json b/package.json
index b493de1..216af0f 100644
--- a/package.json
+++ b/package.json
@@ -44,6 +44,7 @@
     "node": ">=20"
   },
   "devDependencies": {
+    "@types/diff": "^7.0.2",
     "@types/node": "^25.1.0",
     "typescript": "^5.7.3"
   },