diff --git a/package-lock.json b/package-lock.json
index dab92919..b759ab26 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -11,7 +11,7 @@
       "dependencies": {
         "@agentclientprotocol/sdk": "1.5.0",
         "@anthropic-ai/claude-agent-sdk": "0.3.280",
-        "diff": "^8.0.3",
+        "diff": "9.0.0",
         "zod": "4.6.5"
       },
       "bin": {
@@ -1680,9 +1680,9 @@
       }
     },
     "node_modules/diff": {
-      "version": "8.0.4",
-      "resolved": "https://registry.npmjs.org/diff/-/diff-8.0.4.tgz",
-      "integrity": "sha512-DPi0FmjiSU5EvQV0++GFDOJ9ASQUVFh5kD+OzOnYdi7n3Wpm9hWWGfB/O2blfHcMVTL5WkQXSnRiK9makhrcnw==",
+      "version": "9.0.0",
+      "resolved": "https://registry.npmjs.org/diff/-/diff-9.0.0.tgz",
+      "integrity": "sha512-svtcdpS8CgJyqAjEQIXdb3OjhFVVYjzGAPO8WGCmRbrml64SPw/jJD4GoE98aR7r25A0XcgrK3F02yw9R/vhQw==",
       "license": "BSD-3-Clause",
       "engines": {
         "node": ">=0.3.1"
diff --git a/package.json b/package.json
index 8ec0149c..3f6b5e72 100644
--- a/package.json
+++ b/package.json
@@ -67,7 +67,7 @@
   "dependencies": {
     "@agentclientprotocol/sdk": "1.5.0",
     "@anthropic-ai/claude-agent-sdk": "0.3.280",
-    "diff": "^8.0.3",
+    "diff": "9.0.0",
     "zod": "4.6.5"
   },
   "devDependencies": {