diff --git a/package.json b/package.json
index d85a5c2..449379c 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@gui-chat-plugin/set-image-style",
-  "version": "1.1.1",
+  "version": "2.0.0",
   "description": "Set image style modifier plugin for GUIChat",
   "type": "module",
   "main": "./dist/index.cjs",
@@ -35,7 +35,7 @@
     "test": "tsx --test tests/*.test.ts"
   },
   "peerDependencies": {
-    "gui-chat-protocol": "^1.2.0",
+    "gui-chat-protocol": "^2.0.0",
     "vue": "^3.5.0"
   },
   "devDependencies": {
@@ -47,7 +47,7 @@
     "eslint": "^10.8.0",
     "eslint-plugin-vue": "^10.10.0",
     "globals": "^17.8.0",
-    "gui-chat-protocol": "^1.2.0",
+    "gui-chat-protocol": "^2.0.0",
     "tailwindcss": "^4.3.3",
     "tsx": "^4.23.4",
     "typescript": "~6.0.3",
diff --git a/src/core/hostResponse.ts b/src/core/hostResponse.ts
new file mode 100644
index 0000000..76976c5
--- /dev/null
+++ b/src/core/hostResponse.ts
@@ -0,0 +1,14 @@
+import type { ImageGenerationConfig } from "./types";
+
+const isRecord = (value: unknown): value is Record<string, unknown> =>
+  typeof value === "object" && value !== null;
+
+const isOptionalString = (value: unknown): value is string | undefined =>
+  value === undefined || typeof value === "string";
+
+export const isImageGenerationConfig = (
+  value: unknown,
+): value is ImageGenerationConfig =>
+  isRecord(value) &&
+  typeof value["backend"] === "string" &&
+  isOptionalString(value["styleModifier"]);
diff --git a/src/core/plugin.ts b/src/core/plugin.ts
index f468d59..f0929ff 100644
--- a/src/core/plugin.ts
+++ b/src/core/plugin.ts
@@ -9,6 +9,7 @@ import type {
   SetImageStyleJsonData,
   ImageGenerationConfig,
 } from "./types";
+import { isImageGenerationConfig } from "./hostResponse";
 import { TOOL_DEFINITION } from "./definition";
 
 // Re-export for convenience
@@ -27,13 +28,9 @@ export const executeSetImageStyle = async (
 ): Promise<ToolResult<SetImageStyleData, SetImageStyleJsonData>> => {
   const { styleModifier } = args;
 
-  // Check if app context provides image config functions
-  const app = context?.app as {
-    getImageConfig?: () => ImageGenerationConfig;
-    setConfig?: (key: string, value: ImageGenerationConfig) => void;
-  };
+  const app = context?.app;
 
-  if (!app?.getImageConfig) {
+  if (typeof app?.["getImageConfig"] !== "function") {
     return {
       message: "getImageConfig function not available",
       jsonData: {
@@ -44,7 +41,18 @@ export const executeSetImageStyle = async (
   }
 
   try {
-    const config = app.getImageConfig();
+    const config = app["getImageConfig"]();
+
+    if (!isImageGenerationConfig(config)) {
+      return {
+        message: "getImageConfig returned an unrecognized config",
+        jsonData: {
+          success: false,
+          error: "getImageConfig returned an unrecognized config",
+        },
+      };
+    }
+
     const previousStyleModifier = config.styleModifier || "";
 
     // Update the config with new style modifier
diff --git a/tests/hostResponse.test.ts b/tests/hostResponse.test.ts
new file mode 100644
index 0000000..c140c95
--- /dev/null
+++ b/tests/hostResponse.test.ts
@@ -0,0 +1,44 @@
+/**
+ * `context.app.getImageConfig` returns `unknown` since gui-chat-protocol
+ * 2.0.0, so the plugin narrows it here instead of trusting the host's shape.
+ *
+ * Run with: yarn test
+ */
+
+import { test, describe } from "node:test";
+import assert from "node:assert";
+import { isImageGenerationConfig } from "../src/core/hostResponse.js";
+
+describe("isImageGenerationConfig", () => {
+  test("accepts a config naming a backend", () => {
+    assert.equal(isImageGenerationConfig({ backend: "gemini" }), true);
+  });
+
+  test("accepts a config that already carries a style modifier", () => {
+    assert.equal(
+      isImageGenerationConfig({ backend: "gemini", styleModifier: "watercolor" }),
+      true,
+    );
+  });
+
+  test("rejects a config without a backend", () => {
+    assert.equal(isImageGenerationConfig({ styleModifier: "watercolor" }), false);
+  });
+
+  test("rejects a style modifier that is not a string", () => {
+    assert.equal(
+      isImageGenerationConfig({ backend: "gemini", styleModifier: 42 }),
+      false,
+    );
+  });
+
+  test("rejects values that are not a config object", () => {
+    [null, undefined, "ok", 7].forEach((value) => {
+      assert.equal(
+        isImageGenerationConfig(value),
+        false,
+        `should reject ${JSON.stringify(value)}`,
+      );
+    });
+  });
+});
diff --git a/yarn.lock b/yarn.lock
index b1489b4..f4df4a1 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -1051,10 +1051,10 @@ graceful-fs@^4.2.4:
   resolved "https://registry.yarnpkg.com/graceful-fs/-/graceful-fs-4.2.11.tgz#4183e4e8bf08bb6e05bbb2f7d2e0c8f712ca40e3"
   integrity sha512-RbJ5/jmFcNNCcDV5o9eTnBLJ/HszWV0P73bc+Ff4nS/rJj+YaS6IGyiOL0VoBYX+l1Wrl3k63h/KrH+nhJ0XvQ==
 
-gui-chat-protocol@^1.2.0:
-  version "1.2.0"
-  resolved "https://registry.yarnpkg.com/gui-chat-protocol/-/gui-chat-protocol-1.2.0.tgz#8bc7f8d4e31a625aff94fa2c79951b5b80c30145"
-  integrity sha512-5qKQCpXOrH5+QlOWujhYpsG469IB6nsSZ9TOoodsBQ+U5aAPGEEUbvmacyOmPsimHvsDLCxP0S/ZNycWEFHOww==
+gui-chat-protocol@^2.0.0:
+  version "2.0.0"
+  resolved "https://registry.yarnpkg.com/gui-chat-protocol/-/gui-chat-protocol-2.0.0.tgz#96f0f0a115c92f8567b68b9c74a53514e1f3253f"
+  integrity sha512-E02kPSXKH2bX4WAp6TuMjSx4Ftzr2n8XEQtPhZxRCKCBO9ss3Qkx4G5xWeZ6bVUCZtyhB+N8V8Jlv+YRPQJQ9w==
 
 ignore@^5.2.0:
   version "5.3.2"