diff --git a/additions/package-lock.json b/additions/package-lock.json
index 3293eb06..de4b304a 100644
--- a/additions/package-lock.json
+++ b/additions/package-lock.json
@@ -8,7 +8,7 @@
       "name": "additions",
       "version": "0.1.0",
       "dependencies": {
-        "@microsoft/typespec-msgraph": "^1.0.0-Preview.4",
+        "@microsoft/typespec-msgraph": "^1.0.0-Preview.5",
         "@typespec/compiler": "*",
         "@typespec/http": "*",
         "@typespec/openapi": "*",
@@ -29,21 +29,6 @@
         "prettier": "^3.6.2"
       }
     },
-    "node_modules/@alloy-js/core/node_modules/prettier": {
-      "version": "3.6.2",
-      "resolved": "https://registry.npmjs.org/prettier/-/prettier-3.6.2.tgz",
-      "integrity": "sha512-I7AIg5boAr5R0FFtJ6rCfD+LFsWHp81dolrFD8S79U9tb8Az2nGrJncnMSnys+bpQJfRUzqs9hnA81OAA3hCuQ==",
-      "license": "MIT",
-      "bin": {
-        "prettier": "bin/prettier.cjs"
-      },
-      "engines": {
-        "node": ">=14"
-      },
-      "funding": {
-        "url": "https://github.com/prettier/prettier?sponsor=1"
-      }
-    },
     "node_modules/@alloy-js/csharp": {
       "version": "0.20.0",
       "resolved": "https://registry.npmjs.org/@alloy-js/csharp/-/csharp-0.20.0.tgz",
@@ -496,20 +481,20 @@
       }
     },
     "node_modules/@microsoft/typespec-msgraph": {
-      "version": "1.0.0-Preview.4",
-      "resolved": "https://registry.npmjs.org/@microsoft/typespec-msgraph/-/typespec-msgraph-1.0.0-Preview.4.tgz",
-      "integrity": "sha512-4DPZyYPdL7Ebhef6MwoH+HWv8IN//U6m8FVPQeOPVnyTaf3Xaejc6R5LcdOzNITWG8UI/FvZFKG6KIyNkS7zMg==",
+      "version": "1.0.0-Preview.5",
+      "resolved": "https://registry.npmjs.org/@microsoft/typespec-msgraph/-/typespec-msgraph-1.0.0-Preview.5.tgz",
+      "integrity": "sha512-dS8DxzR33lNQPPK7YIPhQw7iCAPzV8U2rFBl60Maits+m8XzEKCJi9e55uHFB+3G55yu0Yf0NvPoUYIdhHYHbw==",
       "license": "MIT",
       "dependencies": {
         "@alloy-js/core": "^0.20.0",
         "@alloy-js/csharp": "^0.20.0",
         "@alloy-js/json": "^0.20.0",
         "@alloy-js/typescript": "^0.20.0",
-        "@typespec/compiler": "~1.4.0",
+        "@typespec/compiler": "~1.5.0",
         "@typespec/emitter-framework": "^0.11.0",
-        "@typespec/http": "~1.4.0",
+        "@typespec/http": "~1.5.0",
         "@xmldom/xmldom": "~0.8.10",
-        "prettier": "~3.2.5",
+        "prettier": "~3.6.2",
         "react": "~18.3.1",
         "react-dom": "~18.3.1",
         "react-reconciler": "~0.29.2"
@@ -518,71 +503,6 @@
         "node": ">=18.0.0"
       }
     },
-    "node_modules/@microsoft/typespec-msgraph/node_modules/@typespec/compiler": {
-      "version": "1.4.0",
-      "resolved": "https://registry.npmjs.org/@typespec/compiler/-/compiler-1.4.0.tgz",
-      "integrity": "sha512-/AFiU3ImuhH/vHKzSGv7I2peewdJ7YLhgMCfFDNk6Ae0a5Ylrc8R1GOATVilisEPBFG9lnjHn3uUcyaZs5VWRw==",
-      "license": "MIT",
-      "dependencies": {
-        "@babel/code-frame": "~7.27.1",
-        "@inquirer/prompts": "^7.4.0",
-        "ajv": "~8.17.1",
-        "change-case": "~5.4.4",
-        "env-paths": "^3.0.0",
-        "globby": "~14.1.0",
-        "is-unicode-supported": "^2.1.0",
-        "mustache": "~4.2.0",
-        "picocolors": "~1.1.1",
-        "prettier": "~3.6.2",
-        "semver": "^7.7.1",
-        "tar": "^7.4.3",
-        "temporal-polyfill": "^0.3.0",
-        "vscode-languageserver": "~9.0.1",
-        "vscode-languageserver-textdocument": "~1.0.12",
-        "yaml": "~2.8.0",
-        "yargs": "~18.0.0"
-      },
-      "bin": {
-        "tsp": "cmd/tsp.js",
-        "tsp-server": "cmd/tsp-server.js"
-      },
-      "engines": {
-        "node": ">=20.0.0"
-      }
-    },
-    "node_modules/@microsoft/typespec-msgraph/node_modules/@typespec/compiler/node_modules/prettier": {
-      "version": "3.6.2",
-      "resolved": "https://registry.npmjs.org/prettier/-/prettier-3.6.2.tgz",
-      "integrity": "sha512-I7AIg5boAr5R0FFtJ6rCfD+LFsWHp81dolrFD8S79U9tb8Az2nGrJncnMSnys+bpQJfRUzqs9hnA81OAA3hCuQ==",
-      "license": "MIT",
-      "bin": {
-        "prettier": "bin/prettier.cjs"
-      },
-      "engines": {
-        "node": ">=14"
-      },
-      "funding": {
-        "url": "https://github.com/prettier/prettier?sponsor=1"
-      }
-    },
-    "node_modules/@microsoft/typespec-msgraph/node_modules/@typespec/http": {
-      "version": "1.4.0",
-      "resolved": "https://registry.npmjs.org/@typespec/http/-/http-1.4.0.tgz",
-      "integrity": "sha512-Y0PDDtBu+oZnwivfhbL0lN6Mk3QiCxZ66DgB5kFjcgKNpnXf0u440PPyaL42a8lbchzz5lVwz+cinyIMI89FIQ==",
-      "license": "MIT",
-      "engines": {
-        "node": ">=20.0.0"
-      },
-      "peerDependencies": {
-        "@typespec/compiler": "^1.4.0",
-        "@typespec/streams": "^0.74.0"
-      },
-      "peerDependenciesMeta": {
-        "@typespec/streams": {
-          "optional": true
-        }
-      }
-    },
     "node_modules/@nodelib/fs.scandir": {
       "version": "2.1.5",
       "resolved": "https://registry.npmjs.org/@nodelib/fs.scandir/-/fs.scandir-2.1.5.tgz",
@@ -680,21 +600,6 @@
         "node": ">=20.0.0"
       }
     },
-    "node_modules/@typespec/compiler/node_modules/prettier": {
-      "version": "3.6.2",
-      "resolved": "https://registry.npmjs.org/prettier/-/prettier-3.6.2.tgz",
-      "integrity": "sha512-I7AIg5boAr5R0FFtJ6rCfD+LFsWHp81dolrFD8S79U9tb8Az2nGrJncnMSnys+bpQJfRUzqs9hnA81OAA3hCuQ==",
-      "license": "MIT",
-      "bin": {
-        "prettier": "bin/prettier.cjs"
-      },
-      "engines": {
-        "node": ">=14"
-      },
-      "funding": {
-        "url": "https://github.com/prettier/prettier?sponsor=1"
-      }
-    },
     "node_modules/@typespec/emitter-framework": {
       "version": "0.11.0",
       "resolved": "https://registry.npmjs.org/@typespec/emitter-framework/-/emitter-framework-0.11.0.tgz",
@@ -1438,9 +1343,9 @@
       }
     },
     "node_modules/prettier": {
-      "version": "3.2.5",
-      "resolved": "https://registry.npmjs.org/prettier/-/prettier-3.2.5.tgz",
-      "integrity": "sha512-3/GWa9aOC0YeD7LUfvOG2NiDyhOWRvt1k+rcKhOuYnMY24iiCphgneUfJDyFXd6rZCAnuLBv6UeAULtrhT/F4A==",
+      "version": "3.6.2",
+      "resolved": "https://registry.npmjs.org/prettier/-/prettier-3.6.2.tgz",
+      "integrity": "sha512-I7AIg5boAr5R0FFtJ6rCfD+LFsWHp81dolrFD8S79U9tb8Az2nGrJncnMSnys+bpQJfRUzqs9hnA81OAA3hCuQ==",
       "license": "MIT",
       "bin": {
         "prettier": "bin/prettier.cjs"
diff --git a/additions/package.json b/additions/package.json
index 97f0c85f..5257356f 100644
--- a/additions/package.json
+++ b/additions/package.json
@@ -4,7 +4,7 @@
   "type": "module",
   "private": true,
   "dependencies": {
-    "@microsoft/typespec-msgraph": "^1.0.0-Preview.4",
+    "@microsoft/typespec-msgraph": "^1.0.0-Preview.5",
     "@typespec/compiler": "latest",
     "@typespec/http": "latest",
     "@typespec/openapi": "latest",