diff --git a/packages/electron/README.md b/packages/electron/README.md
index 3c53f510..c4bcb7bd 100644
--- a/packages/electron/README.md
+++ b/packages/electron/README.md
@@ -170,6 +170,10 @@ Use an explicit override when testing a different OpenCode CLI build or when a u
 ## Native Features Owned Here
 
 - Floating Mini Chat windows.
+- Mini Chat loads from the resolved local UI origin in HMR development, not the
+  API server origin. Bundled mode keeps `openchamber-ui://` assets. Native zoom
+  targets the focused window directly; composer focus adjusts interface scale,
+  while terminal and file-editor focus adjust their own font sizes.
 - New Mini Chat windows default to the managed Chats target. Explicit project/worktree drafts retain their target, existing managed chat sessions reopen in their own directory, and the compact header omits project/branch metadata for Chats. Opening a managed draft back in the main window preserves that target.
 - Multiple native windows.
 - Native notifications.
diff --git a/packages/electron/main.mjs b/packages/electron/main.mjs
index acc378d0..f65e2d90 100644
--- a/packages/electron/main.mjs
+++ b/packages/electron/main.mjs
@@ -258,6 +258,7 @@ const { autoUpdater } = updaterPkg;
 const state = {
   serverHandle: null,
   sidecarUrl: null,
+  localUiUrl: null,
   localOrigin: null,
   apiBaseUrl: null,
   clientToken: null,
@@ -2755,7 +2756,7 @@ const createAdditionalWindow = async (url, runtimeConfig = {}) => {
 const buildMiniChatUrl = ({ mode, sessionId, directory, projectId }) => {
   const base = shouldUsePackagedUi()
     ? buildPackagedUiUrl('/mini-chat.html')
-    : state.localOrigin || state.sidecarUrl;
+    : state.localUiUrl || state.localOrigin || state.sidecarUrl;
   if (!base) {
     throw new Error('Local UI is not available');
   }
@@ -2970,6 +2971,7 @@ const resolveInitialUrl = async () => {
     : localUrl;
 
   state.sidecarUrl = localUrl;
+  state.localUiUrl = localUiUrl;
   const localAvailable = Boolean(localUrl);
 
   const localOrigin = localUrl ? new URL(localUrl).origin : null;