diff --git a/test/harness/package-lock.json b/test/harness/package-lock.json
index 0bb201f5f..1f3fe6c79 100644
--- a/test/harness/package-lock.json
+++ b/test/harness/package-lock.json
@@ -10,7 +10,7 @@
       "license": "ISC",
       "devDependencies": {
         "@github/copilot": "^0.0.411",
-        "@modelcontextprotocol/sdk": "^1.26.0",
+        "@modelcontextprotocol/sdk": "^1.27.1",
         "@types/node": "^25.2.0",
         "openai": "^6.17.0",
         "tsx": "^4.21.0",
@@ -602,9 +602,9 @@
       "license": "MIT"
     },
     "node_modules/@modelcontextprotocol/sdk": {
-      "version": "1.26.0",
-      "resolved": "https://registry.npmjs.org/@modelcontextprotocol/sdk/-/sdk-1.26.0.tgz",
-      "integrity": "sha512-Y5RmPncpiDtTXDbLKswIJzTqu2hyBKxTNsgKqKclDbhIgg1wgtf1fRuvxgTnRfcnxtvvgbIEcqUOzZrJ6iSReg==",
+      "version": "1.27.1",
+      "resolved": "https://registry.npmjs.org/@modelcontextprotocol/sdk/-/sdk-1.27.1.tgz",
+      "integrity": "sha512-sr6GbP+4edBwFndLbM60gf07z0FQ79gaExpnsjMGePXqFcSSb7t6iscpjk9DhFhwd+mTEQrzNafGP8/iGGFYaA==",
       "dev": true,
       "license": "MIT",
       "dependencies": {
diff --git a/test/harness/package.json b/test/harness/package.json
index 65edf4cbc..7a4138989 100644
--- a/test/harness/package.json
+++ b/test/harness/package.json
@@ -12,7 +12,7 @@
   },
   "devDependencies": {
     "@github/copilot": "^0.0.411",
-    "@modelcontextprotocol/sdk": "^1.26.0",
+    "@modelcontextprotocol/sdk": "^1.27.1",
     "@types/node": "^25.2.0",
     "openai": "^6.17.0",
     "tsx": "^4.21.0",