diff --git a/packages/electron/main.mjs b/packages/electron/main.mjs
index 4358e39f..b3c81744 100644
--- a/packages/electron/main.mjs
+++ b/packages/electron/main.mjs
@@ -1089,7 +1089,12 @@ const spawnLocalServer = async () => {
   process.env.OPENCHAMBER_HOST = bindHost;
   process.env.OPENCHAMBER_DIST_DIR = resolveWebDistDir();
   process.env.OPENCHAMBER_RUNTIME = 'desktop';
+  process.env.OPENCHAMBER_OPENCODE_CWD = app.getPath('userData');
   process.env.OPENCHAMBER_DESKTOP_NOTIFY = 'true';
+  try {
+    fs.mkdirSync(process.env.OPENCHAMBER_OPENCODE_CWD, { recursive: true });
+  } catch {
+  }
   if (desktopUiPassword) {
     process.env.OPENCHAMBER_UI_PASSWORD = desktopUiPassword;
   } else {
diff --git a/packages/web/server/lib/opencode/hmr-state-runtime.js b/packages/web/server/lib/opencode/hmr-state-runtime.js
index c06da01c..f98c4c19 100644
--- a/packages/web/server/lib/opencode/hmr-state-runtime.js
+++ b/packages/web/server/lib/opencode/hmr-state-runtime.js
@@ -6,12 +6,19 @@ export const createHmrStateRuntime = (dependencies) => {
     stateKey,
   } = dependencies;
 
+  const getInitialOpenCodeWorkingDirectory = () => {
+    const configured = typeof processLike.env.OPENCHAMBER_OPENCODE_CWD === 'string'
+      ? processLike.env.OPENCHAMBER_OPENCODE_CWD.trim()
+      : '';
+    return configured || os.homedir();
+  };
+
   const getOrCreateHmrState = () => {
     if (!globalThisLike[stateKey]) {
       globalThisLike[stateKey] = {
         openCodeProcess: null,
         openCodePort: null,
-        openCodeWorkingDirectory: os.homedir(),
+        openCodeWorkingDirectory: getInitialOpenCodeWorkingDirectory(),
         isShuttingDown: false,
         signalsAttached: false,
         userProvidedOpenCodePassword: undefined,
diff --git a/packages/web/server/lib/opencode/hmr-state-runtime.test.js b/packages/web/server/lib/opencode/hmr-state-runtime.test.js
new file mode 100644
index 00000000..12211a2e
--- /dev/null
+++ b/packages/web/server/lib/opencode/hmr-state-runtime.test.js
@@ -0,0 +1,24 @@
+import { describe, expect, it } from 'vitest';
+
+import { createHmrStateRuntime } from './hmr-state-runtime.js';
+
+const createRuntime = (env = {}) => createHmrStateRuntime({
+  globalThisLike: {},
+  os: { homedir: () => '/Users/example' },
+  processLike: { env },
+  stateKey: '__testHmrState',
+});
+
+describe('hmr state runtime', () => {
+  it('uses configured OpenCode cwd when provided', () => {
+    const runtime = createRuntime({ OPENCHAMBER_OPENCODE_CWD: '/tmp/openchamber-data' });
+
+    expect(runtime.getOrCreateHmrState().openCodeWorkingDirectory).toBe('/tmp/openchamber-data');
+  });
+
+  it('falls back to home directory without configured OpenCode cwd', () => {
+    const runtime = createRuntime();
+
+    expect(runtime.getOrCreateHmrState().openCodeWorkingDirectory).toBe('/Users/example');
+  });
+});