diff --git a/apps/api/package.json b/apps/api/package.json
index 2325fb1..288f1ee 100644
--- a/apps/api/package.json
+++ b/apps/api/package.json
@@ -15,7 +15,7 @@
     "@flow/shared": "workspace:*",
     "@modelcontextprotocol/sdk": "^1.29.0",
     "hono": "^4.7.0",
-    "zod": "^3.24.1"
+    "zod": "^4.4.3"
   },
   "devDependencies": {
     "@cloudflare/workers-types": "^4.20250712.0",
diff --git a/packages/shared/package.json b/packages/shared/package.json
index 0eaa87b..b8af8f1 100644
--- a/packages/shared/package.json
+++ b/packages/shared/package.json
@@ -12,7 +12,7 @@
     "typecheck": "tsc --noEmit"
   },
   "dependencies": {
-    "zod": "^3.24.1"
+    "zod": "^4.4.3"
   },
   "devDependencies": {
     "typescript": "^5.7.2"
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index db3d582..5ee71a1 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -22,13 +22,13 @@ importers:
         version: link:../../packages/shared
       '@modelcontextprotocol/sdk':
         specifier: ^1.29.0
-        version: 1.29.0(zod@3.25.76)
+        version: 1.29.0(zod@4.4.3)
       hono:
         specifier: ^4.7.0
         version: 4.12.32
       zod:
-        specifier: ^3.24.1
-        version: 3.25.76
+        specifier: ^4.4.3
+        version: 4.4.3
     devDependencies:
       '@cloudflare/workers-types':
         specifier: ^4.20250712.0
@@ -109,8 +109,8 @@ importers:
   packages/shared:
     dependencies:
       zod:
-        specifier: ^3.24.1
-        version: 3.25.76
+        specifier: ^4.4.3
+        version: 4.4.3
     devDependencies:
       typescript:
         specifier: ^5.7.2
@@ -2234,8 +2234,8 @@ packages:
     peerDependencies:
       zod: ^3.25.28 || ^4
 
-  zod@3.25.76:
-    resolution: {integrity: sha512-gzUt/qt81nXsFGKIFcC3YnfEAx5NkunCfnDlvuBSSFS02bcXu4Lmea0AFIUwbLWxWPx3d9p8S5QoaujKcNQxcQ==}
+  zod@4.4.3:
+    resolution: {integrity: sha512-ytENFjIJFl2UwYglde2jchW2Hwm4GJFLDiSXWdTrJQBIN9Fcyp7n4DhxJEiWNAJMV1/BqWfW/kkg71UDcHJyTQ==}
 
 snapshots:
 
@@ -2761,7 +2761,7 @@ snapshots:
       '@jridgewell/resolve-uri': 3.1.2
       '@jridgewell/sourcemap-codec': 1.5.5
 
-  '@modelcontextprotocol/sdk@1.29.0(zod@3.25.76)':
+  '@modelcontextprotocol/sdk@1.29.0(zod@4.4.3)':
     dependencies:
       '@hono/node-server': 1.19.15(hono@4.12.32)
       ajv: 8.20.0
@@ -2778,8 +2778,8 @@ snapshots:
       json-schema-typed: 8.0.2
       pkce-challenge: 5.0.1
       raw-body: 3.0.2
-      zod: 3.25.76
-      zod-to-json-schema: 3.25.2(zod@3.25.76)
+      zod: 4.4.3
+      zod-to-json-schema: 3.25.2(zod@4.4.3)
     transitivePeerDependencies:
       - supports-color
 
@@ -4107,8 +4107,8 @@ snapshots:
 
   zimmerframe@1.1.4: {}
 
-  zod-to-json-schema@3.25.2(zod@3.25.76):
+  zod-to-json-schema@3.25.2(zod@4.4.3):
     dependencies:
-      zod: 3.25.76
+      zod: 4.4.3
 
-  zod@3.25.76: {}
+  zod@4.4.3: {}