diff --git a/server/install-plugin.js b/server/install-plugin.js
index c8cbb81..d6ba3c1 100644
--- a/server/install-plugin.js
+++ b/server/install-plugin.js
@@ -1,6 +1,46 @@
 const fs = require("fs");
 const path = require("path");
 
+// .ignis metadata helpers
+async function getIgnisMeta(vaultPath) {
+  const ignisDir = path.join(vaultPath, ".ignis");
+  const metaFile = path.join(ignisDir, "meta.json");
+
+  try {
+    const content = await fs.promises.readFile(metaFile, "utf-8");
+    return JSON.parse(content);
+  } catch (e) {
+    return {};
+  }
+}
+
+async function setIgnisMeta(vaultPath, data) {
+  const ignisDir = path.join(vaultPath, ".ignis");
+  const metaFile = path.join(ignisDir, "meta.json");
+
+  await fs.promises.mkdir(ignisDir, { recursive: true });
+  await fs.promises.writeFile(metaFile, JSON.stringify(data, null, 2));
+}
+
+async function checkPluginInstalled(vaultPath) {
+  const pluginDir = path.join(
+    vaultPath,
+    ".obsidian",
+    "plugins",
+    "ignis-bridge",
+  );
+  const manifestPath = path.join(pluginDir, "manifest.json");
+  const mainPath = path.join(pluginDir, "main.js");
+
+  try {
+    await fs.promises.access(manifestPath);
+    await fs.promises.access(mainPath);
+    return true;
+  } catch (e) {
+    return false;
+  }
+}
+
 async function installPluginInVault(vaultPath) {
   const obsidianDir = path.join(vaultPath, ".obsidian");
   const pluginDir = path.join(obsidianDir, "plugins", "ignis-bridge");
@@ -62,4 +102,10 @@ async function installPluginInAllVaults(vaultRoot) {
   }
 }
 
-module.exports = { installPluginInVault, installPluginInAllVaults };
+module.exports = {
+  installPluginInVault,
+  installPluginInAllVaults,
+  getIgnisMeta,
+  setIgnisMeta,
+  checkPluginInstalled,
+};
diff --git a/server/routes/vault.js b/server/routes/vault.js
index 1d8503d..daf30eb 100644
--- a/server/routes/vault.js
+++ b/server/routes/vault.js
@@ -2,6 +2,12 @@ const express = require("express");
 const fs = require("fs");
 const config = require("../config");
 const path = require("path");
+const {
+  checkPluginInstalled,
+  getIgnisMeta,
+  setIgnisMeta,
+  installPluginInVault,
+} = require("../install-plugin");
 
 const router = express.Router();
 
@@ -19,7 +25,7 @@ router.get("/list", (req, res) => {
 });
 
 // GET /api/vault/info?vault=<id> - returns info for a specific vault
-router.get("/info", (req, res) => {
+router.get("/info", async (req, res) => {
   const vaultId = req.query.vault || config.defaultVaultId;
   const vaultPath = config.getVaultPath(vaultId);
 
@@ -27,12 +33,19 @@ router.get("/info", (req, res) => {
     return res.status(404).json({ error: "Vault not found", id: vaultId });
   }
 
+  const pluginInstalled = await checkPluginInstalled(vaultPath);
+  const ignisMeta = await getIgnisMeta(vaultPath);
+
   res.json({
     id: vaultId,
     name: vaultId,
     path: vaultPath,
     platform: process.platform,
     version: config.obsidianVersion,
+    ignisPlugin: {
+      installed: pluginInstalled,
+      prompted: ignisMeta.pluginPrompted || false,
+    },
   });
 });
 
@@ -143,4 +156,42 @@ router.delete("/remove", async (req, res) => {
   }
 });
 
+// POST /api/vault/install-plugin { vault, dismiss } - install plugin or mark as prompted
+router.post("/install-plugin", async (req, res) => {
+  const vaultId = req.body?.vault;
+  const dismiss = req.body?.dismiss || false;
+
+  if (!vaultId) {
+    return res.status(400).json({ error: "Missing vault ID" });
+  }
+
+  const vaultPath = config.getVaultPath(vaultId);
+
+  if (!vaultPath) {
+    return res.status(404).json({ error: "Vault not found" });
+  }
+
+  try {
+    const meta = await getIgnisMeta(vaultPath);
+
+    if (dismiss) {
+      // User clicked "Don't Ask Again" or "Not Now"
+      meta.pluginPrompted = true;
+      await setIgnisMeta(vaultPath, meta);
+
+      return res.json({ ok: true, prompted: true });
+    } else {
+      // User wants to install the plugin
+      const installed = await installPluginInVault(vaultPath);
+
+      meta.pluginPrompted = true;
+      await setIgnisMeta(vaultPath, meta);
+
+      return res.json({ ok: true, installed, prompted: true });
+    }
+  } catch (e) {
+    res.status(500).json({ error: e.message, code: e.code });
+  }
+});
+
 module.exports = router;
diff --git a/src/services/vault-service.js b/src/services/vault-service.js
index 64a0d85..0480d6b 100644
--- a/src/services/vault-service.js
+++ b/src/services/vault-service.js
@@ -48,6 +48,8 @@ export const vaultService = {
       body: JSON.stringify({ name }),
     });
 
+    this._setVaultTrust(name);
+
     return this.listVaults();
   },
 
@@ -121,6 +123,10 @@ export const vaultService = {
     target.location.href = "/?vault=" + encodeURIComponent(id);
   },
 
+  _setVaultTrust(vaultId, trusted = true) {
+    localStorage.setItem("enable-plugin-" + vaultId, String(trusted));
+  },
+
   _migrateLocalStorage(oldId, newId) {
     const pluginKey = "enable-plugin-";
 
diff --git a/src/shims/loader.js b/src/shims/loader.js
index d517d61..d80be06 100644
--- a/src/shims/loader.js
+++ b/src/shims/loader.js
@@ -16,6 +16,7 @@ import * as osShim from "./node/os.js";
 import * as netShim from "./node/net.js";
 import * as httpShim from "./node/http.js";
 import { vaultService } from "../services/vault-service.js";
+import { showPluginInstallDialog } from "../ui/bootstrap.js";
 
 const DEBUG = true;
 const _accessLog = new Map(); // "module.property" -> count
@@ -208,6 +209,8 @@ window.__currentVaultId =
         path: "/",
       };
 
+      window.__ignisPlugin = info.ignisPlugin || null;
+
       console.log("[ignis] Vault:", window.__vaultConfig);
       console.log("[ignis] Obsidian version:", window.__obsidianVersion);
     } else {
@@ -259,4 +262,25 @@ window.__currentVaultId =
 
 installRequestUrlShim();
 
+// Check if plugin install prompt is needed (once per session, after workspace loads)
+if (
+  window.__ignisPlugin &&
+  !window.__ignisPlugin.installed &&
+  !window.__ignisPlugin.prompted
+) {
+  const vaultId = window.__currentVaultId;
+
+  const observer = new MutationObserver(() => {
+    if (document.querySelector(".workspace")) {
+      observer.disconnect();
+      showPluginInstallDialog(vaultId);
+    }
+  });
+
+  observer.observe(document.documentElement, {
+    childList: true,
+    subtree: true,
+  });
+}
+
 console.log("[ignis] Shim loader initialized");
diff --git a/src/ui/bootstrap.js b/src/ui/bootstrap.js
index 0028722..9e4345d 100644
--- a/src/ui/bootstrap.js
+++ b/src/ui/bootstrap.js
@@ -48,6 +48,42 @@ export function showConfirmDialog(
   });
 }
 
+export function showPluginInstallDialog(vaultId) {
+  return new Promise((resolve) => {
+    const dialog = new window.IgnisUI.PluginInstallDialog({
+      target: document.body,
+    });
+
+    dialog.$on("install", async () => {
+      try {
+        await fetch("/api/vault/install-plugin", {
+          method: "POST",
+          headers: { "Content-Type": "application/json" },
+          body: JSON.stringify({ vault: vaultId }),
+        });
+      } catch (e) {
+        console.error("[ignis] Failed to install plugin:", e);
+      }
+      dialog.$destroy();
+      resolve("install");
+    });
+
+    dialog.$on("dismiss", async () => {
+      try {
+        await fetch("/api/vault/install-plugin", {
+          method: "POST",
+          headers: { "Content-Type": "application/json" },
+          body: JSON.stringify({ vault: vaultId, dismiss: true }),
+        });
+      } catch (e) {
+        console.error("[ignis] Failed to dismiss plugin prompt:", e);
+      }
+      dialog.$destroy();
+      resolve("dismiss");
+    });
+  });
+}
+
 export function showPromptDialog(
   title,
   label,
diff --git a/src/ui/components/layout/PluginInstallDialog.svelte b/src/ui/components/layout/PluginInstallDialog.svelte
new file mode 100644
index 0000000..34db792
--- /dev/null
+++ b/src/ui/components/layout/PluginInstallDialog.svelte
@@ -0,0 +1,89 @@
+<script>
+  import { createEventDispatcher } from "svelte";
+  import Modal from "./Modal.svelte";
+  import Button from "../input/Button.svelte";
+  import { Puzzle, Download, X } from "lucide-svelte";
+
+  export let width = "500px";
+
+  const dispatch = createEventDispatcher();
+
+  let modalRef;
+  let installing = false;
+
+  function onInstall() {
+    installing = true;
+    dispatch("install");
+  }
+
+  function onDismiss() {
+    modalRef.dismiss();
+    dispatch("dismiss");
+  }
+
+  function onEscape() {
+    onDismiss();
+  }
+
+  export function dismiss() {
+    modalRef.dismiss();
+  }
+</script>
+
+<Modal title="Ignis Bridge Plugin" {width} bind:this={modalRef} on:escape={onEscape} closeOnOverlayClick={false}>
+  <svelte:fragment slot="icon">
+    <Puzzle size="1.25rem" />
+  </svelte:fragment>
+
+  <div class="dialog-body">
+    <p class="dialog-message">This vault doesn't have the Ignis Bridge plugin installed.</p>
+    <p class="dialog-description">
+      The plugin adds additional functionality such as file uploads.
+      Obsidian will work without it, but some features will be unavailable.
+    </p>
+  </div>
+
+  <svelte:fragment slot="footer">
+    <div class="dialog-footer">
+      <Button variant="secondary" on:click={onDismiss}>
+        <svelte:fragment slot="icon">
+          <X size="0.875rem" />
+        </svelte:fragment>
+        Not Now
+      </Button>
+      <Button variant="primary" on:click={onInstall} disabled={installing}>
+        <svelte:fragment slot="icon">
+          <Download size="0.875rem" />
+        </svelte:fragment>
+        {installing ? "Installing..." : "Install Plugin"}
+      </Button>
+    </div>
+  </svelte:fragment>
+</Modal>
+
+<style>
+  .dialog-body {
+    padding: 1.25rem 1.5rem;
+    border-bottom: 1px solid var(--background-modifier-border);
+  }
+
+  .dialog-message {
+    margin: 0 0 0.5rem;
+    font-size: 1.125rem;
+    font-weight: 600;
+    color: var(--text-normal);
+  }
+
+  .dialog-description {
+    margin: 0;
+    font-size: 0.875rem;
+    color: var(--text-muted);
+    line-height: 1.5;
+  }
+
+  .dialog-footer {
+    display: flex;
+    justify-content: flex-end;
+    gap: 0.5rem;
+  }
+</style>
diff --git a/src/ui/index.js b/src/ui/index.js
index 11fd0d4..6fdb228 100644
--- a/src/ui/index.js
+++ b/src/ui/index.js
@@ -2,3 +2,4 @@ export { default as VaultManager } from "./views/VaultManager.svelte";
 export { default as MessageDialog } from "./components/layout/MessageDialog.svelte";
 export { default as ConfirmDialog } from "./components/layout/ConfirmDialog.svelte";
 export { default as PromptDialog } from "./components/layout/PromptDialog.svelte";
+export { default as PluginInstallDialog } from "./components/layout/PluginInstallDialog.svelte";