diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index fbb765f7a..2a9be895d 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -681,48 +681,56 @@ packages:
     engines: {node: ^20.19.0 || >=22.12.0}
     cpu: [arm64]
     os: [linux]
+    libc: [glibc]
 
   '@oxfmt/binding-linux-arm64-musl@0.47.0':
     resolution: {integrity: sha512-IxtQC/sbBi4ubbY+MdwdanRWrG9InQJVZqyMsBa5IUaQcnSg86gQme574HxXMC1p4bo4YhV99zQ+wNnGCvEgzw==}
     engines: {node: ^20.19.0 || >=22.12.0}
     cpu: [arm64]
     os: [linux]
+    libc: [musl]
 
   '@oxfmt/binding-linux-ppc64-gnu@0.47.0':
     resolution: {integrity: sha512-EWXEhOMbWO0q6eJSbu0QLkU8cKi0ljlYLngeDs2Ocu/pm1rrLwyQiYzlFbdnMRURI4w9ndr1sI9rSbhlJ5o23Q==}
     engines: {node: ^20.19.0 || >=22.12.0}
     cpu: [ppc64]
     os: [linux]
+    libc: [glibc]
 
   '@oxfmt/binding-linux-riscv64-gnu@0.47.0':
     resolution: {integrity: sha512-tZrjS11TUiDuEpRaqdk8K9F9xETRyKXfuZKmdeW+Gj7coBnm7+8sBEfyt033EAFEQSlkniAXvBLh+Qja2ioGBQ==}
     engines: {node: ^20.19.0 || >=22.12.0}
     cpu: [riscv64]
     os: [linux]
+    libc: [glibc]
 
   '@oxfmt/binding-linux-riscv64-musl@0.47.0':
     resolution: {integrity: sha512-KBFy+2CFKUCZzYwX2ZOPQKck1vjQbz+hextuc19G4r0WRJwadfAeuQMQRQvB+Ivc8brlbOVg7et8K7E467440g==}
     engines: {node: ^20.19.0 || >=22.12.0}
     cpu: [riscv64]
     os: [linux]
+    libc: [musl]
 
   '@oxfmt/binding-linux-s390x-gnu@0.47.0':
     resolution: {integrity: sha512-REUPFKVGSiK99B+9eaPhluEVglzaoj/SMykNC5SUiV2RSsBfV5lWN7Y0iCIc251Wz3GaeAGZsJ/zj3gjarxdFg==}
     engines: {node: ^20.19.0 || >=22.12.0}
     cpu: [s390x]
     os: [linux]
+    libc: [glibc]
 
   '@oxfmt/binding-linux-x64-gnu@0.47.0':
     resolution: {integrity: sha512-KVftVSVEDeIfRW3TIeLe3aNI/iY4m1fu5mDwHcisKMZSCMKLkrhFsjowC7o9RoqNPxbbglm2+/6KAKBIts2t0Q==}
     engines: {node: ^20.19.0 || >=22.12.0}
     cpu: [x64]
     os: [linux]
+    libc: [glibc]
 
   '@oxfmt/binding-linux-x64-musl@0.47.0':
     resolution: {integrity: sha512-DTsmGEaA2860Aq5VUyDO8/MT9NFxwVL93RnRYmpMwK6DsSkThmvEpqoUDDljziEpAedMRG19SCogrNbINSbLUQ==}
     engines: {node: ^20.19.0 || >=22.12.0}
     cpu: [x64]
     os: [linux]
+    libc: [musl]
 
   '@oxfmt/binding-openharmony-arm64@0.47.0':
     resolution: {integrity: sha512-8r5BDro7fLOBoq1JXHLVSs55OlrxQhEso4HVo0TcY7OXJUPYfjPoOaYL5us+yIwqyP9rQwN+rxuiNFSmaxSuOQ==}
@@ -782,66 +790,79 @@ packages:
     resolution: {integrity: sha512-2QxQrM+KQ7DAW4o22j+XZ6RKdxjLD7BOWTP0Bv0tmjdyhXSsr2Ul1oJDQqh9Zf5qOwTuTc7Ek83mOFaKnodPjg==}
     cpu: [arm]
     os: [linux]
+    libc: [glibc]
 
   '@rollup/rollup-linux-arm-musleabihf@4.60.2':
     resolution: {integrity: sha512-TbziEu2DVsTEOPif2mKWkMeDMLoYjx95oESa9fkQQK7r/Orta0gnkcDpzwufEcAO2BLBsD7mZkXGFqEdMRRwfw==}
     cpu: [arm]
     os: [linux]
+    libc: [musl]
 
   '@rollup/rollup-linux-arm64-gnu@4.60.2':
     resolution: {integrity: sha512-bO/rVDiDUuM2YfuCUwZ1t1cP+/yqjqz+Xf2VtkdppefuOFS2OSeAfgafaHNkFn0t02hEyXngZkxtGqXcXwO8Rg==}
     cpu: [arm64]
     os: [linux]
+    libc: [glibc]
 
   '@rollup/rollup-linux-arm64-musl@4.60.2':
     resolution: {integrity: sha512-hr26p7e93Rl0Za+JwW7EAnwAvKkehh12BU1Llm9Ykiibg4uIr2rbpxG9WCf56GuvidlTG9KiiQT/TXT1yAWxTA==}
     cpu: [arm64]
     os: [linux]
+    libc: [musl]
 
   '@rollup/rollup-linux-loong64-gnu@4.60.2':
     resolution: {integrity: sha512-pOjB/uSIyDt+ow3k/RcLvUAOGpysT2phDn7TTUB3n75SlIgZzM6NKAqlErPhoFU+npgY3/n+2HYIQVbF70P9/A==}
     cpu: [loong64]
     os: [linux]
+    libc: [glibc]
 
   '@rollup/rollup-linux-loong64-musl@4.60.2':
     resolution: {integrity: sha512-2/w+q8jszv9Ww1c+6uJT3OwqhdmGP2/4T17cu8WuwyUuuaCDDJ2ojdyYwZzCxx0GcsZBhzi3HmH+J5pZNXnd+Q==}
     cpu: [loong64]
     os: [linux]
+    libc: [musl]
 
   '@rollup/rollup-linux-ppc64-gnu@4.60.2':
     resolution: {integrity: sha512-11+aL5vKheYgczxtPVVRhdptAM2H7fcDR5Gw4/bTcteuZBlH4oP9f5s9zYO9aGZvoGeBpqXI/9TZZihZ609wKw==}
     cpu: [ppc64]
     os: [linux]
+    libc: [glibc]
 
   '@rollup/rollup-linux-ppc64-musl@4.60.2':
     resolution: {integrity: sha512-i16fokAGK46IVZuV8LIIwMdtqhin9hfYkCh8pf8iC3QU3LpwL+1FSFGej+O7l3E/AoknL6Dclh2oTdnRMpTzFQ==}
     cpu: [ppc64]
     os: [linux]
+    libc: [musl]
 
   '@rollup/rollup-linux-riscv64-gnu@4.60.2':
     resolution: {integrity: sha512-49FkKS6RGQoriDSK/6E2GkAsAuU5kETFCh7pG4yD/ylj9rKhTmO3elsnmBvRD4PgJPds5W2PkhC82aVwmUcJ7A==}
     cpu: [riscv64]
     os: [linux]
+    libc: [glibc]
 
   '@rollup/rollup-linux-riscv64-musl@4.60.2':
     resolution: {integrity: sha512-mjYNkHPfGpUR00DuM1ZZIgs64Hpf4bWcz9Z41+4Q+pgDx73UwWdAYyf6EG/lRFldmdHHzgrYyge5akFUW0D3mQ==}
     cpu: [riscv64]
     os: [linux]
+    libc: [musl]
 
   '@rollup/rollup-linux-s390x-gnu@4.60.2':
     resolution: {integrity: sha512-ALyvJz965BQk8E9Al/JDKKDLH2kfKFLTGMlgkAbbYtZuJt9LU8DW3ZoDMCtQpXAltZxwBHevXz5u+gf0yA0YoA==}
     cpu: [s390x]
     os: [linux]
+    libc: [glibc]
 
   '@rollup/rollup-linux-x64-gnu@4.60.2':
     resolution: {integrity: sha512-UQjrkIdWrKI626Du8lCQ6MJp/6V1LAo2bOK9OTu4mSn8GGXIkPXk/Vsp4bLHCd9Z9Iz2OTEaokUE90VweJgIYQ==}
     cpu: [x64]
     os: [linux]
+    libc: [glibc]
 
   '@rollup/rollup-linux-x64-musl@4.60.2':
     resolution: {integrity: sha512-bTsRGj6VlSdn/XD4CGyzMnzaBs9bsRxy79eTqTCBsA8TMIEky7qg48aPkvJvFe1HyzQ5oMZdg7AnVlWQSKLTnw==}
     cpu: [x64]
     os: [linux]
+    libc: [musl]
 
   '@rollup/rollup-openbsd-x64@4.60.2':
     resolution: {integrity: sha512-6d4Z3534xitaA1FcMWP7mQPq5zGwBmGbhphh2DwaA1aNIXUu3KTOfwrWpbwI4/Gr0uANo7NTtaykFyO2hPuFLg==}
@@ -914,24 +935,28 @@ packages:
     engines: {node: '>= 20'}
     cpu: [arm64]
     os: [linux]
+    libc: [glibc]
 
   '@tailwindcss/oxide-linux-arm64-musl@4.2.4':
     resolution: {integrity: sha512-bBADEGAbo4ASnppIziaQJelekCxdMaxisrk+fB7Thit72IBnALp9K6ffA2G4ruj90G9XRS2VQ6q2bCKbfFV82g==}
     engines: {node: '>= 20'}
     cpu: [arm64]
     os: [linux]
+    libc: [musl]
 
   '@tailwindcss/oxide-linux-x64-gnu@4.2.4':
     resolution: {integrity: sha512-7Mx25E4WTfnht0TVRTyC00j3i0M+EeFe7wguMDTlX4mRxafznw0CA8WJkFjWYH5BlgELd1kSjuU2JiPnNZbJDA==}
     engines: {node: '>= 20'}
     cpu: [x64]
     os: [linux]
+    libc: [glibc]
 
   '@tailwindcss/oxide-linux-x64-musl@4.2.4':
     resolution: {integrity: sha512-2wwJRF7nyhOR0hhHoChc04xngV3iS+akccHTGtz965FwF0up4b2lOdo6kI1EbDaEXKgvcrFBYcYQQ/rrnWFVfA==}
     engines: {node: '>= 20'}
     cpu: [x64]
     os: [linux]
+    libc: [musl]
 
   '@tailwindcss/oxide-wasm32-wasi@4.2.4':
     resolution: {integrity: sha512-FQsqApeor8Fo6gUEklzmaa9994orJZZDBAlQpK2Mq+DslRKFJeD6AjHpBQ0kZFQohVr8o85PPh8eOy86VlSCmw==}
@@ -1000,30 +1025,35 @@ packages:
     engines: {node: '>= 10'}
     cpu: [arm64]
     os: [linux]
+    libc: [glibc]
 
   '@tauri-apps/cli-linux-arm64-musl@2.11.0':
     resolution: {integrity: sha512-DtSE8ZBlB9H+L+eHkfZ3myt00EVEyAB3e41juEHoE2qT88fgVlJvyrwa9SZYc/xTwCS9TnmK+R84tpg+ZsAg7Q==}
     engines: {node: '>= 10'}
     cpu: [arm64]
     os: [linux]
+    libc: [musl]
 
   '@tauri-apps/cli-linux-riscv64-gnu@2.11.0':
     resolution: {integrity: sha512-5QdgS4LD+kntClI1aj2JmwjW38LosNXxwCe8viIHEwqYIWuMPdNEIau6/cLogI38Yzx9DnfCPRfEWLyI+5li8Q==}
     engines: {node: '>= 10'}
     cpu: [riscv64]
     os: [linux]
+    libc: [glibc]
 
   '@tauri-apps/cli-linux-x64-gnu@2.11.0':
     resolution: {integrity: sha512-5UynPXo3Zq9khjVdAbD+YogeLltdVUeOah2ioSIM3tu6H7wY9vMy6rgGJhv9r5R8ZXmk9GttMippdqYJWrnLnA==}
     engines: {node: '>= 10'}
     cpu: [x64]
     os: [linux]
+    libc: [glibc]
 
   '@tauri-apps/cli-linux-x64-musl@2.11.0':
     resolution: {integrity: sha512-CNz7fHbApz1Zyhhq73jtGn9JqgNEV/lIWnTnUo6h6ujw+mHsTmkLszvJSM8W6JBaDjNpTTFr/RSNoVL5FMwcTg==}
     engines: {node: '>= 10'}
     cpu: [x64]
     os: [linux]
+    libc: [musl]
 
   '@tauri-apps/cli-win32-arm64-msvc@2.11.0':
     resolution: {integrity: sha512-K+br+VXZ+Xx0n/9FdWohpW5Ugq+2FQUpJScqcPl1hTxXfh3fgjYgt4qA2NgrjlJo+zZPNrmUMl+NLvm0ufEqBQ==}
@@ -2068,24 +2098,28 @@ packages:
     engines: {node: '>= 12.0.0'}
     cpu: [arm64]
     os: [linux]
+    libc: [glibc]
 
   lightningcss-linux-arm64-musl@1.32.0:
     resolution: {integrity: sha512-UpQkoenr4UJEzgVIYpI80lDFvRmPVg6oqboNHfoH4CQIfNA+HOrZ7Mo7KZP02dC6LjghPQJeBsvXhJod/wnIBg==}
     engines: {node: '>= 12.0.0'}
     cpu: [arm64]
     os: [linux]
+    libc: [musl]
 
   lightningcss-linux-x64-gnu@1.32.0:
     resolution: {integrity: sha512-V7Qr52IhZmdKPVr+Vtw8o+WLsQJYCTd8loIfpDaMRWGUZfBOYEJeyJIkqGIDMZPwPx24pUMfwSxxI8phr/MbOA==}
     engines: {node: '>= 12.0.0'}
     cpu: [x64]
     os: [linux]
+    libc: [glibc]
 
   lightningcss-linux-x64-musl@1.32.0:
     resolution: {integrity: sha512-bYcLp+Vb0awsiXg/80uCRezCYHNg1/l3mt0gzHnWV9XP1W5sKa5/TCdGWaR/zBM2PeF/HbsQv/j2URNOiVuxWg==}
     engines: {node: '>= 12.0.0'}
     cpu: [x64]
     os: [linux]
+    libc: [musl]
 
   lightningcss-win32-arm64-msvc@1.32.0:
     resolution: {integrity: sha512-8SbC8BR40pS6baCM8sbtYDSwEVQd4JlFTOlaD3gWGHfThTcABnNDBda6eTZeqbofalIJhFx0qKzgHJmcPTnGdw==}
diff --git a/src/App.vue b/src/App.vue
index 813c9f365..a0c3e649c 100644
--- a/src/App.vue
+++ b/src/App.vue
@@ -215,9 +215,15 @@ function newQuery() {
 async function openConnectionQuery(connectionId: string) {
   const connection = connectionStore.getConfig(connectionId);
   if (!connection) return;
-  const options = await getDatabaseOptions(connectionId);
   connectionStore.activeConnectionId = connectionId;
-  queryStore.createTab(connectionId, connection.database || options[0] || "");
+  const tabId = queryStore.createTab(connectionId, connection.database || "");
+  try {
+    await connectionStore.ensureConnected(connectionId);
+    const options = await getDatabaseOptions(connectionId);
+    if (!connection.database && options[0]) queryStore.updateDatabase(tabId, options[0]);
+  } catch (e: any) {
+    toast(t("connection.connectFailed", { message: e?.message || String(e) }), 5000);
+  }
 }
 
 async function changeActiveConnection(connectionId: string) {
@@ -225,9 +231,15 @@ async function changeActiveConnection(connectionId: string) {
   if (!tab) return;
   const connection = connectionStore.getConfig(connectionId);
   if (!connection) return;
-  const options = await getDatabaseOptions(connectionId);
-  queryStore.updateConnection(tab.id, connectionId, connection.database || options[0] || "");
+  queryStore.updateConnection(tab.id, connectionId, connection.database || "");
   connectionStore.activeConnectionId = connectionId;
+  try {
+    await connectionStore.ensureConnected(connectionId);
+    const options = await getDatabaseOptions(connectionId);
+    if (!connection.database && options[0]) queryStore.updateDatabase(tab.id, options[0]);
+  } catch (e: any) {
+    toast(t("connection.connectFailed", { message: e?.message || String(e) }), 5000);
+  }
 }
 
 function changeActiveDatabase(database: string) {
diff --git a/src/components/connection/ConnectionErrorIndicator.vue b/src/components/connection/ConnectionErrorIndicator.vue
new file mode 100644
index 000000000..a4ae87289
--- /dev/null
+++ b/src/components/connection/ConnectionErrorIndicator.vue
@@ -0,0 +1,74 @@
+<script setup lang="ts">
+import { computed } from "vue";
+import { useI18n } from "vue-i18n";
+import { AlertTriangle, X } from "lucide-vue-next";
+import {
+    Popover,
+    PopoverContent,
+    PopoverTrigger,
+} from "@/components/ui/popover";
+import { useConnectionStore } from "@/stores/connectionStore";
+
+const props = withDefaults(
+    defineProps<{
+        connectionId?: string | null;
+        triggerClass?: string;
+    }>(),
+    {
+        connectionId: null,
+        triggerClass: "",
+    },
+);
+
+const { t } = useI18n();
+const connectionStore = useConnectionStore();
+
+const errorMessage = computed(() =>
+    props.connectionId
+        ? connectionStore.connectionErrors[props.connectionId]
+        : "",
+);
+
+function clearError() {
+    if (props.connectionId)
+        connectionStore.clearConnectionError(props.connectionId);
+}
+</script>
+
+<template>
+    <Popover v-if="errorMessage">
+        <PopoverTrigger as-child>
+            <button
+                type="button"
+                class="inline-flex h-4 w-4 shrink-0 items-center justify-center rounded text-amber-500 hover:bg-amber-500/10 hover:text-amber-600 focus:outline-none focus:ring-1 focus:ring-amber-500/40"
+                :class="triggerClass"
+                :title="t('connection.lastError')"
+                @click.stop
+            >
+                <AlertTriangle class="h-3.5 w-3.5" />
+            </button>
+        </PopoverTrigger>
+        <PopoverContent side="top" class="w-72 gap-2 p-2 text-xs" @click.stop>
+            <div class="flex items-start gap-2">
+                <div class="min-w-0 flex-1">
+                    <div class="font-medium text-foreground">
+                        {{ t("connection.lastError") }}
+                    </div>
+                    <div
+                        class="mt-1 max-h-36 overflow-auto whitespace-pre-wrap break-words text-muted-foreground"
+                    >
+                        {{ errorMessage }}
+                    </div>
+                </div>
+                <button
+                    type="button"
+                    class="shrink-0 rounded p-0.5 text-muted-foreground hover:bg-muted hover:text-foreground"
+                    :title="t('connection.clearError')"
+                    @click="clearError"
+                >
+                    <X class="h-3.5 w-3.5" />
+                </button>
+            </div>
+        </PopoverContent>
+    </Popover>
+</template>
diff --git a/src/components/editor/AiAssistant.vue b/src/components/editor/AiAssistant.vue
index b827b4a74..f208784fc 100644
--- a/src/components/editor/AiAssistant.vue
+++ b/src/components/editor/AiAssistant.vue
@@ -42,6 +42,7 @@ import { useConnectionStore } from "@/stores/connectionStore";
 import { connectionIconType } from "@/lib/connectionPresentation";
 import DatabaseIcon from "@/components/icons/DatabaseIcon.vue";
 import { useQueryStore } from "@/stores/queryStore";
+import { useToast } from "@/composables/useToast";
 import { buildAiContext, runAiStream, type AiAction } from "@/lib/ai";
 import {
   aiTestConnection,
@@ -59,6 +60,7 @@ const { t } = useI18n();
 const settings = useSettingsStore();
 const connectionStore = useConnectionStore();
 const queryStore = useQueryStore();
+const { toast } = useToast();
 
 interface ChatMessage {
   role: "user" | "assistant";
@@ -133,7 +135,7 @@ async function loadDatabases() {
   await loadDatabaseOptions(props.connection.id);
 }
 
-function changeConnection(connectionId: string) {
+async function changeConnection(connectionId: string) {
   const conn = connectionStore.getConfig(connectionId);
   if (!conn) return;
   connectionStore.activeConnectionId = connectionId;
@@ -143,6 +145,11 @@ function changeConnection(connectionId: string) {
   } else {
     queryStore.createTab(connectionId, conn.database || "");
   }
+  try {
+    await loadDatabaseOptions(connectionId);
+  } catch (e: any) {
+    toast(t("connection.connectFailed", { message: e?.message || String(e) }), 5000);
+  }
 }
 
 function changeDatabase(database: string) {
diff --git a/src/components/sidebar/TreeItem.vue b/src/components/sidebar/TreeItem.vue
index d6fc12ff4..181ba86c0 100644
--- a/src/components/sidebar/TreeItem.vue
+++ b/src/components/sidebar/TreeItem.vue
@@ -60,6 +60,7 @@ import { qualifiedTableName as buildQualifiedTableName, quoteTableIdentifier } f
 import { treeNodeRowAction } from "@/lib/treeNodeClick";
 import { isTauriRuntime } from "@/lib/tauriRuntime";
 import DatabaseIcon from "@/components/icons/DatabaseIcon.vue";
+import ConnectionErrorIndicator from "@/components/connection/ConnectionErrorIndicator.vue";
 import { Dialog, DialogContent, DialogHeader, DialogTitle, DialogFooter } from "@/components/ui/dialog";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
@@ -304,9 +305,13 @@ async function openData() {
 async function newQuery() {
   const node = props.node;
   if (!node.connectionId) return;
-  await connectionStore.ensureConnected(node.connectionId);
-  connectionStore.activeConnectionId = node.connectionId;
-  queryStore.createTab(node.connectionId, node.database || "", undefined, "query");
+  try {
+    await connectionStore.ensureConnected(node.connectionId);
+    connectionStore.activeConnectionId = node.connectionId;
+    queryStore.createTab(node.connectionId, node.database || "", undefined, "query");
+  } catch (e: any) {
+    toast(t("connection.connectFailed", { message: e?.message || String(e) }), 5000);
+  }
 }
 
 async function refresh() {
@@ -919,6 +924,11 @@ const isDragging = computed(() => dragState.active && dragState.draggedId === pr
             "
             class="w-1.5 h-1.5 rounded-full bg-green-500 shrink-0"
           />
+          <ConnectionErrorIndicator
+            v-if="node.type === 'connection'"
+            :connection-id="node.connectionId"
+            trigger-class="h-4 w-4"
+          />
           <button
             v-if="canPin"
             class="rounded p-0.5 text-muted-foreground hover:bg-muted-foreground/15 hover:text-foreground focus:opacity-100"
diff --git a/src/components/ui/popover/Popover.vue b/src/components/ui/popover/Popover.vue
new file mode 100644
index 000000000..a3fe9ac64
--- /dev/null
+++ b/src/components/ui/popover/Popover.vue
@@ -0,0 +1,19 @@
+<script setup lang="ts">
+import type { PopoverRootEmits, PopoverRootProps } from 'reka-ui'
+import { PopoverRoot, useForwardPropsEmits } from 'reka-ui'
+
+const props = defineProps<PopoverRootProps>()
+const emits = defineEmits<PopoverRootEmits>()
+
+const forwarded = useForwardPropsEmits(props, emits)
+</script>
+
+<template>
+  <PopoverRoot
+    v-slot="slotProps"
+    data-slot="popover"
+    v-bind="forwarded"
+  >
+    <slot v-bind="slotProps" />
+  </PopoverRoot>
+</template>
diff --git a/src/components/ui/popover/PopoverAnchor.vue b/src/components/ui/popover/PopoverAnchor.vue
new file mode 100644
index 000000000..e96a12114
--- /dev/null
+++ b/src/components/ui/popover/PopoverAnchor.vue
@@ -0,0 +1,15 @@
+<script setup lang="ts">
+import type { PopoverAnchorProps } from 'reka-ui'
+import { PopoverAnchor } from 'reka-ui'
+
+const props = defineProps<PopoverAnchorProps>()
+</script>
+
+<template>
+  <PopoverAnchor
+    data-slot="popover-anchor"
+    v-bind="props"
+  >
+    <slot />
+  </PopoverAnchor>
+</template>
diff --git a/src/components/ui/popover/PopoverContent.vue b/src/components/ui/popover/PopoverContent.vue
new file mode 100644
index 000000000..b5fccb450
--- /dev/null
+++ b/src/components/ui/popover/PopoverContent.vue
@@ -0,0 +1,45 @@
+<script setup lang="ts">
+import type { PopoverContentEmits, PopoverContentProps } from 'reka-ui'
+import type { HTMLAttributes } from 'vue'
+import { reactiveOmit } from '@vueuse/core'
+import {
+  PopoverContent,
+  PopoverPortal,
+  useForwardPropsEmits,
+} from 'reka-ui'
+import { cn } from '@/lib/utils'
+
+defineOptions({
+  inheritAttrs: false,
+})
+
+const props = withDefaults(
+  defineProps<PopoverContentProps & { class?: HTMLAttributes['class'] }>(),
+  {
+    align: 'center',
+    sideOffset: 4,
+  },
+)
+const emits = defineEmits<PopoverContentEmits>()
+
+const delegatedProps = reactiveOmit(props, 'class')
+
+const forwarded = useForwardPropsEmits(delegatedProps, emits)
+</script>
+
+<template>
+  <PopoverPortal>
+    <PopoverContent
+      data-slot="popover-content"
+      v-bind="{ ...$attrs, ...forwarded }"
+      :class="
+        cn(
+          'bg-popover text-popover-foreground data-open:animate-in data-closed:animate-out data-closed:fade-out-0 data-open:fade-in-0 data-closed:zoom-out-95 data-open:zoom-in-95 data-[side=bottom]:slide-in-from-top-2 data-[side=left]:slide-in-from-right-2 data-[side=right]:slide-in-from-left-2 data-[side=top]:slide-in-from-bottom-2 ring-foreground/10 flex flex-col gap-2.5 rounded-lg p-2.5 text-sm shadow-md ring-1 duration-100 z-50 w-72 origin-(--reka-popover-content-transform-origin) outline-hidden',
+          props.class,
+        )
+      "
+    >
+      <slot />
+    </PopoverContent>
+  </PopoverPortal>
+</template>
diff --git a/src/components/ui/popover/PopoverDescription.vue b/src/components/ui/popover/PopoverDescription.vue
new file mode 100644
index 000000000..4c7968a48
--- /dev/null
+++ b/src/components/ui/popover/PopoverDescription.vue
@@ -0,0 +1,17 @@
+<script setup lang="ts">
+import type { HTMLAttributes } from 'vue'
+import { cn } from '@/lib/utils'
+
+const props = defineProps<{
+  class?: HTMLAttributes['class']
+}>()
+</script>
+
+<template>
+  <p
+    data-slot="popover-description"
+    :class="cn('text-muted-foreground', props.class)"
+  >
+    <slot />
+  </p>
+</template>
diff --git a/src/components/ui/popover/PopoverHeader.vue b/src/components/ui/popover/PopoverHeader.vue
new file mode 100644
index 000000000..61f3e0af5
--- /dev/null
+++ b/src/components/ui/popover/PopoverHeader.vue
@@ -0,0 +1,17 @@
+<script setup lang="ts">
+import type { HTMLAttributes } from 'vue'
+import { cn } from '@/lib/utils'
+
+const props = defineProps<{
+  class?: HTMLAttributes['class']
+}>()
+</script>
+
+<template>
+  <div
+    data-slot="popover-header"
+    :class="cn('flex flex-col gap-0.5 text-sm', props.class)"
+  >
+    <slot />
+  </div>
+</template>
diff --git a/src/components/ui/popover/PopoverTitle.vue b/src/components/ui/popover/PopoverTitle.vue
new file mode 100644
index 000000000..2da9e8760
--- /dev/null
+++ b/src/components/ui/popover/PopoverTitle.vue
@@ -0,0 +1,17 @@
+<script setup lang="ts">
+import type { HTMLAttributes } from 'vue'
+import { cn } from '@/lib/utils'
+
+const props = defineProps<{
+  class?: HTMLAttributes['class']
+}>()
+</script>
+
+<template>
+  <div
+    data-slot="popover-title"
+    :class="cn('font-medium cn-font-heading', props.class)"
+  >
+    <slot />
+  </div>
+</template>
diff --git a/src/components/ui/popover/PopoverTrigger.vue b/src/components/ui/popover/PopoverTrigger.vue
new file mode 100644
index 000000000..0d410658d
--- /dev/null
+++ b/src/components/ui/popover/PopoverTrigger.vue
@@ -0,0 +1,15 @@
+<script setup lang="ts">
+import type { PopoverTriggerProps } from 'reka-ui'
+import { PopoverTrigger } from 'reka-ui'
+
+const props = defineProps<PopoverTriggerProps>()
+</script>
+
+<template>
+  <PopoverTrigger
+    data-slot="popover-trigger"
+    v-bind="props"
+  >
+    <slot />
+  </PopoverTrigger>
+</template>
diff --git a/src/components/ui/popover/index.ts b/src/components/ui/popover/index.ts
new file mode 100644
index 000000000..16337762e
--- /dev/null
+++ b/src/components/ui/popover/index.ts
@@ -0,0 +1,7 @@
+export { default as Popover } from './Popover.vue'
+export { default as PopoverAnchor } from './PopoverAnchor.vue'
+export { default as PopoverContent } from './PopoverContent.vue'
+export { default as PopoverDescription } from './PopoverDescription.vue'
+export { default as PopoverHeader } from './PopoverHeader.vue'
+export { default as PopoverTitle } from './PopoverTitle.vue'
+export { default as PopoverTrigger } from './PopoverTrigger.vue'
diff --git a/src/i18n/locales/en.ts b/src/i18n/locales/en.ts
index 7419e412d..f5660e2f3 100644
--- a/src/i18n/locales/en.ts
+++ b/src/i18n/locales/en.ts
@@ -76,6 +76,8 @@ export default {
     connecting: "Connecting to {name}...",
     connectSuccess: "Connected to {name}",
     connectFailed: "Connection failed: {message}",
+    lastError: "Connection error",
+    clearError: "Clear connection error",
     saveFailed: "Failed to save connection: {message}",
     loadFailed: "Failed to load saved connections: {message}",
     sshTunnel: "SSH Tunnel",
diff --git a/src/i18n/locales/zh-CN.ts b/src/i18n/locales/zh-CN.ts
index 5beee2adb..cc6d49159 100644
--- a/src/i18n/locales/zh-CN.ts
+++ b/src/i18n/locales/zh-CN.ts
@@ -75,6 +75,8 @@ export default {
     connecting: "正在连接 {name}...",
     connectSuccess: "已连接 {name}",
     connectFailed: "连接失败：{message}",
+    lastError: "连接错误",
+    clearError: "清除连接错误",
     saveFailed: "保存连接失败：{message}",
     loadFailed: "加载已保存连接失败：{message}",
     sshTunnel: "SSH 隧道",
diff --git a/src/stores/connectionStore.ts b/src/stores/connectionStore.ts
index 0e453aa61..127bb725f 100644
--- a/src/stores/connectionStore.ts
+++ b/src/stores/connectionStore.ts
@@ -35,6 +35,7 @@ export const useConnectionStore = defineStore("connection", () => {
   const treeNodes = ref<TreeNode[]>([]);
   const pinnedTreeNodeIds = ref<Set<string>>(loadPinnedTreeNodeIds());
   const connectedIds = ref<Set<string>>(new Set());
+  const connectionErrors = ref<Record<string, string>>({});
   const editingConnectionId = ref<string | null>(null);
   const completionTablesCache = ref<Record<string, SqlCompletionTable[]>>({});
   const completionColumnsCache = ref<Record<string, ColumnInfo[]>>({});
@@ -86,6 +87,31 @@ export const useConnectionStore = defineStore("connection", () => {
     return connections.value.find((c) => c.id === connectionId);
   }
 
+  function connectionErrorMessage(error: unknown): string {
+    if (error instanceof Error) return error.message;
+    return String(error);
+  }
+
+  function setConnectionError(connectionId: string, message: string) {
+    connectionErrors.value = {
+      ...connectionErrors.value,
+      [connectionId]: message,
+    };
+  }
+
+  function clearConnectionError(connectionId: string) {
+    if (!connectionErrors.value[connectionId]) return;
+    const next = { ...connectionErrors.value };
+    delete next[connectionId];
+    connectionErrors.value = next;
+  }
+
+  function recordConnectionError(connectionId: string, error: unknown): string {
+    const message = connectionErrorMessage(error);
+    setConnectionError(connectionId, message);
+    return message;
+  }
+
   function normalizeConnection(config: ConnectionConfig): ConnectionConfig {
     const labelMap: Record<string, string> = {
       mysql: "MySQL",
@@ -203,6 +229,7 @@ export const useConnectionStore = defineStore("connection", () => {
     const nextConnections = connections.value.filter((c) => c.id !== id);
     await persistConnections(nextConnections);
     connections.value = nextConnections;
+    clearConnectionError(id);
     sidebarLayout.value = removeConnectionFromSidebarLayout(sidebarLayout.value, id);
     rebuildTreeNodes();
     persistSidebarLayoutDebounced();
@@ -233,6 +260,8 @@ export const useConnectionStore = defineStore("connection", () => {
       const id = await api.connectDb(config);
       activeConnectionId.value = id;
       connectedIds.value.add(id);
+      clearConnectionError(config.id);
+      if (id !== config.id) clearConnectionError(id);
 
       const node: TreeNode = {
         id,
@@ -249,6 +278,9 @@ export const useConnectionStore = defineStore("connection", () => {
         treeNodes.value.push(node);
       }
       return id;
+    } catch (e) {
+      recordConnectionError(config.id, e);
+      throw e;
     } finally {
       const node = findNode(treeNodes.value, config.id);
       if (node) node.isLoading = false;
@@ -272,10 +304,20 @@ export const useConnectionStore = defineStore("connection", () => {
   async function ensureConnected(connectionId: string) {
     if (connectedIds.value.has(connectionId)) return;
     const config = getConfig(connectionId);
-    if (!config) throw new Error("Connection config not found");
-    await api.connectDb(config);
-    connectedIds.value.add(connectionId);
-    activeConnectionId.value = connectionId;
+    if (!config) {
+      const error = new Error("Connection config not found");
+      recordConnectionError(connectionId, error);
+      throw error;
+    }
+    try {
+      await api.connectDb(config);
+      connectedIds.value.add(connectionId);
+      activeConnectionId.value = connectionId;
+      clearConnectionError(connectionId);
+    } catch (e) {
+      recordConnectionError(connectionId, e);
+      throw e;
+    }
   }
 
   async function loadDatabases(connectionId: string) {
@@ -858,6 +900,7 @@ export const useConnectionStore = defineStore("connection", () => {
       connections.value.push(normalized);
     }
     connectedIds.value.add(normalized.id);
+    clearConnectionError(normalized.id);
   }
 
   return {
@@ -865,6 +908,10 @@ export const useConnectionStore = defineStore("connection", () => {
     activeConnectionId,
     treeNodes,
     connectedIds,
+    connectionErrors,
+    setConnectionError,
+    clearConnectionError,
+    recordConnectionError,
     sidebarLayout,
     getConfig,
     isTreeNodePinned,