diff --git a/jest.config.js b/jest.config.js
index 366ed0b..85a47d1 100644
--- a/jest.config.js
+++ b/jest.config.js
@@ -4,6 +4,7 @@ const config = {
   testEnvironment: 'node',
   silent: true,
   forceExit: true,
+  maxWorkers: 1,
   moduleFileExtensions: ['ts', 'tsx', 'js', 'jsx', 'json', 'node'],
   extensionsToTreatAsEsm: ['.ts'],
   testMatch: ['**/__tests__/**/*.+(ts|tsx|js)', '**/?(*.)+(spec|test).+(ts|tsx|js)'],
@@ -38,4 +39,4 @@ const config = {
   ],
 };
 
-export default config;
\ No newline at end of file
+export default config;
diff --git a/tests/config.integration.test.ts b/tests/config.integration.test.ts
new file mode 100644
index 0000000..60098f6
--- /dev/null
+++ b/tests/config.integration.test.ts
@@ -0,0 +1,85 @@
+import { jest } from "@jest/globals";
+import path from "path";
+import { mkdtempSync, readFileSync, writeFileSync, mkdirSync } from "node:fs";
+import os from "os";
+import { ConfigChatType, ConfigType } from "../src/types.ts";
+
+// mock external modules to keep memory usage low
+jest.unstable_mockModule("../src/helpers/readGoogleSheet", () => ({
+  readGoogleSheet: jest.fn(),
+}));
+jest.unstable_mockModule(
+  "google-auth-library/build/src/auth/oauth2client",
+  () => ({ OAuth2Client: class {} }),
+);
+jest.unstable_mockModule("google-auth-library", () => ({
+  GoogleAuth: class {},
+}));
+
+const config = await import("../src/config.ts");
+const {
+  readConfig,
+  writeConfig,
+  generateConfig,
+  convertChatConfig,
+  setConfigPath,
+} = config;
+const yaml = await import("js-yaml");
+
+describe("config integration", () => {
+  it("loads chats from files and updates chat file", () => {
+    const tmp = mkdtempSync(path.join(os.tmpdir(), "cfg-"));
+    const chatsDir = path.join(tmp, "data", "chats");
+    mkdirSync(chatsDir, { recursive: true });
+    writeFileSync(path.join(chatsDir, "a.yml"), "name: a\n");
+    writeFileSync(path.join(chatsDir, "b.yml"), "name: b\n");
+    const cfg = generateConfig();
+    cfg.useChatsDir = true;
+    cfg.chatsDir = chatsDir;
+    cfg.chats = [];
+    const configPath = path.join(tmp, "config.yml");
+    writeConfig(configPath, cfg);
+    const loaded = readConfig(configPath);
+    expect(loaded.chats.map((c) => c.name)).toEqual(["a", "b"]);
+    const chatFile = path.join(chatsDir, "a.yml");
+    const before = readFileSync(chatFile, "utf8");
+    loaded.chats[0].description = "updated";
+    writeConfig(configPath, loaded);
+    const after = readFileSync(chatFile, "utf8");
+    expect(after).not.toBe(before);
+    expect(after).toMatch(/description: updated/);
+  });
+
+  it("splits and merges config using convertChatConfig", () => {
+    const tmp = mkdtempSync(path.join(os.tmpdir(), "cfg-"));
+    const configPath = path.join(tmp, "config.yml");
+    const chatsDir = path.join(tmp, "data", "chats");
+    const cfg = generateConfig();
+    cfg.useChatsDir = false;
+    cfg.chatsDir = chatsDir;
+    cfg.chats = [
+      {
+        name: "chat1",
+        agent_name: "chat1",
+        completionParams: {},
+        chatParams: {},
+        toolParams: {},
+      } as ConfigChatType,
+    ];
+    writeConfig(configPath, cfg);
+    setConfigPath(configPath);
+
+    convertChatConfig("split");
+    const splitCfg = yaml.load(readFileSync(configPath, "utf8")) as ConfigType;
+    expect(splitCfg.useChatsDir).toBe(true);
+    expect(splitCfg.chats).toBeUndefined();
+    const chatFile = path.join(chatsDir, "chat1.yml");
+    const saved = yaml.load(readFileSync(chatFile, "utf8")) as ConfigChatType;
+    expect(saved.name).toBe("chat1");
+
+    convertChatConfig("merge");
+    const mergedCfg = yaml.load(readFileSync(configPath, "utf8")) as ConfigType;
+    expect(mergedCfg.useChatsDir).toBe(false);
+    expect(mergedCfg.chats[0].name).toBe("chat1");
+  });
+});
diff --git a/tests/configChatsDir.test.ts b/tests/configChatsDir.test.ts
index 72c5260..3438666 100644
--- a/tests/configChatsDir.test.ts
+++ b/tests/configChatsDir.test.ts
@@ -69,7 +69,7 @@ describe("chats dir mode", () => {
       ...mod.useConfig().chats[0],
       buttonsSync: { sheetId: "id", sheetName: "name" },
     } as ConfigChatType;
-    await mod.syncButtons(chat, {} as any);
+    await mod.syncButtons(chat, {} as unknown as Record<string, unknown>);
     const afterCfg = yaml.load(readFileSync(configPath, "utf8")) as Record<
       string,
       unknown