diff --git a/addons/nuxeo-drive/elements/nuxeo-drive-desktop-packages.js b/addons/nuxeo-drive/elements/nuxeo-drive-desktop-packages.js
index c957d7f66b..4fcaa52334 100644
--- a/addons/nuxeo-drive/elements/nuxeo-drive-desktop-packages.js
+++ b/addons/nuxeo-drive/elements/nuxeo-drive-desktop-packages.js
@@ -40,6 +40,7 @@ Polymer({
       .table {
         font-family: var(--nuxeo-app-font);
         line-height: 3.5;
+        text-align: left;
       }
 
       .row {
@@ -54,20 +55,26 @@ Polymer({
       .header {
         background-color: var(--nuxeo-table-header-background);
         color: var(--nuxeo-table-header-titles);
-        font-weight: 400;
+        font-weight: bold;
         height: 56px;
         display: flex;
         flex-direction: row;
       }
 
       .cell {
-        padding: 0 24px 0 24px;
+        padding: 0 16px;
         min-height: 46px;
         overflow: hidden;
+        display: flex;
+        align-items: center;
       }
 
       paper-button {
         line-height: normal;
+        margin: 0;
+        padding: 0;
+        min-width: 0;
+        text-transform: none;
       }
 
       .platform {
@@ -77,7 +84,7 @@ Polymer({
         font-size: 0.9em;
         letter-spacing: 0.04em;
         line-height: 130%;
-        margin: 0 0.2em 0.2em 0;
+        margin: 0;
         padding: 0.06em 0.3em;
         vertical-align: baseline;
         white-space: nowrap;
@@ -89,12 +96,12 @@ Polymer({
     <div class="table">
       <div class="header">
         <div class="cell flex">[[i18n('driveDesktopPackages.platform')]]</div>
-        <div class="cell flex-3">[[i18n('driveDesktopPackages.install')]]</div>
+        <div class="cell flex-2">[[i18n('driveDesktopPackages.install')]]</div>
       </div>
       <template is="dom-repeat" items="[[packages]]" as="pkg">
         <div class="row">
           <div class="cell flex"><span class="platform">[[pkg.platform]]</span></div>
-          <div class="cell flex-3">
+          <div class="cell flex-2">
             <a href$="[[pkg.url]]" tabindex="-1" target="_blank">
               <paper-button noink> [[pkg.name]] </paper-button>
             </a>
diff --git a/addons/nuxeo-drive/elements/nuxeo-drive-download-button.js b/addons/nuxeo-drive/elements/nuxeo-drive-download-button.js
index bf91499fc8..f644fcde03 100644
--- a/addons/nuxeo-drive/elements/nuxeo-drive-download-button.js
+++ b/addons/nuxeo-drive/elements/nuxeo-drive-download-button.js
@@ -20,6 +20,7 @@ import { mixinBehaviors } from '@polymer/polymer/lib/legacy/class.js';
 import { I18nBehavior } from '@nuxeo/nuxeo-ui-elements/nuxeo-i18n-behavior.js';
 import { isPageProviderDisplayBehavior } from '../../../elements/select-all-helpers.js';
 import './nuxeo-drive-icons.js';
+import { base64UrlSafeEncode, navigateAndShowFallback } from './nuxeo-drive-utils.js';
 
 window.nuxeo = window.nuxeo || {};
 const baseUrl = window.nuxeo.baseUrl || window.location.origin + window.location.pathname;
@@ -44,6 +45,11 @@ class NuxeoDriveDownloadButton extends mixinBehaviors([I18nBehavior], PolymerEle
         reflectToAttribute: true,
         value: false,
       },
+
+      _installExpanded: {
+        type: Boolean,
+        value: false,
+      },
     };
   }
 
@@ -51,10 +57,9 @@ class NuxeoDriveDownloadButton extends mixinBehaviors([I18nBehavior], PolymerEle
     return html`
       <style include="nuxeo-action-button-styles"></style>
 
-      <nuxeo-resource id="token" path="/token" params='{"application": "Nuxeo Drive"}'></nuxeo-resource>
       <div
         class="action"
-        on-tap="_download"
+        on-click="_download"
         hidden$="[[!_isAvailable(documents.splices, documents.items.splices, documents.items.length, documents.selectedItems.splices, documents.selectedItems.length)]]"
       >
         <paper-icon-button noink icon="nuxeo-drive:download" id="driveBtn" aria-labelledby="label"></paper-icon-button>
@@ -63,12 +68,59 @@ class NuxeoDriveDownloadButton extends mixinBehaviors([I18nBehavior], PolymerEle
       </div>
 
       <nuxeo-dialog id="dialog" with-backdrop>
-        <div class="vertical layout">
-          <h1>[[i18n('driveEditButton.dialog.heading')]]</h1>
-          <nuxeo-drive-desktop-packages></nuxeo-drive-desktop-packages>
+        <style>
+          #dialog {
+            margin-top: 0;
+            top: 50%;
+            transform: translateY(-50%);
+            max-height: 80vh;
+          }
+
+          .dialog-content {
+            padding: 16px 24px;
+          }
+
+          .dialog-content h1 {
+            margin: 0 0 12px;
+            font-size: 1.6em;
+          }
+
+          .dialog-content p {
+            color: var(--primary-text-color, #333);
+            margin: 0 0 16px;
+          }
+
+          .close-btn {
+            border: 1px solid var(--nuxeo-primary-color, #0066ff);
+            color: var(--nuxeo-primary-color, #0066ff);
+            text-transform: uppercase;
+            font-size: 0.9em;
+            padding: 0.5em 1em;
+          }
+
+          .buttons {
+            justify-content: flex-end;
+          }
+
+          .install-link {
+            display: inline-block;
+            margin-top: 4px;
+            font-size: 0.9em;
+          }
+        </style>
+        <div class="dialog-content">
+          <h1>[[i18n('driveButton.dialog.heading')]]</h1>
+          <p>[[i18n('driveButton.dialog.description')]]</p>
+          <template is="dom-if" if="[[_installExpanded]]">
+            <p>[[i18n('driveButton.dialog.install.prompt')]]</p>
+            <nuxeo-drive-desktop-packages></nuxeo-drive-desktop-packages>
+          </template>
+          <template is="dom-if" if="[[!_installExpanded]]">
+            <a class="install-link" href="#" on-click="_toggleInstall">[[i18n('driveButton.install.dialog.hint')]]</a>
+          </template>
         </div>
         <div class="buttons">
-          <paper-button dialog-dismiss class="secondary">[[i18n('command.close')]]</paper-button>
+          <paper-button dialog-dismiss class="close-btn">[[i18n('command.close')]]</paper-button>
         </div>
       </nuxeo-dialog>
 
@@ -79,7 +131,7 @@ class NuxeoDriveDownloadButton extends mixinBehaviors([I18nBehavior], PolymerEle
   _isAvailable() {
     return isPageProviderDisplayBehavior(this.documents)
       ? (this.documents.selectedItems || this.documents.items || []).length > 0
-      : this.documents && this.documents.length > 0;
+      : this.documents?.length > 0;
   }
 
   _download() {
@@ -95,21 +147,17 @@ class NuxeoDriveDownloadButton extends mixinBehaviors([I18nBehavior], PolymerEle
       return;
     }
 
-    this.$.token
-      .get()
-      .then((response) => {
-        const tokens = response.entries.map((token) => token.id);
-
-        if (!tokens || !tokens.length) {
-          this.$.dialog.toggle();
-          return;
-        }
-
-        window.open(this.directDownloadUrl, '_top');
-      })
-      .catch((err) => {
-        this._showError(err && err.userMessage ? err.userMessage : this.i18n('driveDownload.directTransfer.failed'));
-      });
+    try {
+      this._installExpanded = false;
+      navigateAndShowFallback(this, this.directDownloadUrl);
+    } catch (e) {
+      this._showError(e.userMessage || e.message);
+    }
+  }
+
+  _toggleInstall(e) {
+    e.preventDefault();
+    this._installExpanded = true;
   }
 
   _showError(message) {
@@ -122,11 +170,11 @@ class NuxeoDriveDownloadButton extends mixinBehaviors([I18nBehavior], PolymerEle
       return (this.documents.selectedItems || this.documents.items || []).map((doc) => doc.uid);
     }
 
-    if (this.documents && this.documents.length > 0) {
+    if (this.documents?.length > 0) {
       return this.documents.map((doc) => doc.uid);
     }
 
-    if (this.document && this.document.uid) {
+    if (this.document?.uid) {
       return [this.document.uid];
     }
 
@@ -173,25 +221,15 @@ class NuxeoDriveDownloadButton extends mixinBehaviors([I18nBehavior], PolymerEle
     const serverBytes = new TextEncoder().encode(server);
     if (serverBytes.length > 255) {
       const userMessage = this.i18n('driveDownload.serverUrlTooLong');
-      const err = new Error(this.i18n('driveDownload.serverUrlTooLong'));
+      const err = new Error(userMessage);
       err.userMessage = userMessage;
       throw err;
     }
     const payload = new Uint8Array([scheme, serverBytes.length, ...serverBytes, allUuidHex.length, ...uuidBinary]);
 
-    const b64 = this._base64UrlSafeEncode(payload);
+    const b64 = base64UrlSafeEncode(payload);
     return `nxdrive://direct-download/${b64}`;
   }
-
-  _base64UrlSafeEncode(bytes) {
-    let binary = '';
-    bytes.forEach((byte) => {
-      binary += String.fromCharCode(byte);
-    });
-
-    let b64 = btoa(binary);
-    return b64.replace(/\+/g, '-').replace(/\//g, '_').replace(/=+$/, '');
-  }
 }
 
 customElements.define(NuxeoDriveDownloadButton.is, NuxeoDriveDownloadButton);
diff --git a/addons/nuxeo-drive/elements/nuxeo-drive-edit-button.js b/addons/nuxeo-drive/elements/nuxeo-drive-edit-button.js
index 16ccb1babf..953f12d149 100644
--- a/addons/nuxeo-drive/elements/nuxeo-drive-edit-button.js
+++ b/addons/nuxeo-drive/elements/nuxeo-drive-edit-button.js
@@ -21,6 +21,7 @@ import { Polymer } from '@polymer/polymer/lib/legacy/polymer-fn.js';
 import { html } from '@polymer/polymer/lib/utils/html-tag.js';
 import { I18nBehavior } from '@nuxeo/nuxeo-ui-elements/nuxeo-i18n-behavior.js';
 import { FiltersBehavior } from '@nuxeo/nuxeo-ui-elements/nuxeo-filters-behavior.js';
+import { navigateAndShowFallback } from './nuxeo-drive-utils.js';
 
 /**
 `nuxeo-drive-edit-button`
@@ -31,10 +32,8 @@ Polymer({
   _template: html`
     <style include="nuxeo-action-button-styles"></style>
 
-    <nuxeo-resource id="token" path="/token" params='{"application": "Nuxeo Drive"}'></nuxeo-resource>
-
     <template is="dom-if" if="[[_isAvailable(document,blob)]]">
-      <div class="action" on-tap="_go">
+      <div class="action" on-click="_go">
         <paper-icon-button noink icon="icons:open-in-new" id="driveBtn" aria-labelledby="label"></paper-icon-button>
         <span class="label" hidden$="[[!showLabel]]" id="label">[[i18n('driveEditButton.tooltip')]]</span>
         <nuxeo-tooltip>[[i18n('driveEditButton.tooltip')]]</nuxeo-tooltip>
@@ -42,14 +41,63 @@ Polymer({
     </template>
 
     <nuxeo-dialog id="dialog" with-backdrop>
-      <div class="vertical layout">
-        <h1>[[i18n('driveEditButton.dialog.heading')]]</h1>
-        <nuxeo-drive-desktop-packages></nuxeo-drive-desktop-packages>
+      <style>
+        #dialog {
+          margin-top: 0;
+          top: 50%;
+          transform: translateY(-50%);
+          max-height: 80vh;
+        }
+
+        .dialog-content {
+          padding: 16px 24px;
+        }
+
+        .dialog-content h1 {
+          margin: 0 0 12px;
+          font-size: 1.6em;
+        }
+
+        .dialog-content p {
+          color: var(--primary-text-color, #333);
+          margin: 0 0 16px;
+        }
+
+        .close-btn {
+          border: 1px solid var(--nuxeo-primary-color, #0066ff);
+          color: var(--nuxeo-primary-color, #0066ff);
+          text-transform: uppercase;
+          font-size: 0.9em;
+          padding: 0.5em 1em;
+        }
+
+        .buttons {
+          justify-content: flex-end;
+        }
+
+        .install-link {
+          display: inline-block;
+          margin-top: 4px;
+          font-size: 0.9em;
+        }
+      </style>
+      <div class="dialog-content">
+        <h1>[[i18n('driveButton.dialog.heading')]]</h1>
+        <p>[[i18n('driveButton.dialog.description')]]</p>
+        <template is="dom-if" if="[[_installExpanded]]">
+          <p>[[i18n('driveButton.dialog.install.prompt')]]</p>
+          <nuxeo-drive-desktop-packages></nuxeo-drive-desktop-packages>
+        </template>
+        <template is="dom-if" if="[[!_installExpanded]]">
+          <a class="install-link" href="#" on-click="_toggleInstall">[[i18n('driveButton.install.dialog.hint')]]</a>
+        </template>
       </div>
       <div class="buttons">
-        <paper-button dialog-dismiss class="secondary">[[i18n('command.close')]]</paper-button>
+        <paper-button dialog-dismiss class="close-btn">[[i18n('command.close')]]</paper-button>
       </div>
     </nuxeo-dialog>
+
+    <paper-toast id="toast"></paper-toast>
   `,
 
   is: 'nuxeo-drive-edit-button',
@@ -67,23 +115,32 @@ Polymer({
       reflectToAttribute: true,
       value: false,
     },
+
+    _installExpanded: {
+      type: Boolean,
+      value: false,
+    },
   },
 
   _isAvailable(doc, blob) {
-    return (
-      this.hasPermission(doc, 'Write') && !this.isProxy(doc) && blob && (!blob.appLinks || blob.appLinks.length === 0)
-    );
+    return this.hasPermission(doc, 'Write') && !this.isProxy(doc) && blob && !blob.appLinks?.length;
   },
 
   _go() {
-    this.$.token.get().then((response) => {
-      const tokens = response.entries.map((token) => token.id);
-      if (!tokens || !tokens.length) {
-        this.$.dialog.toggle();
-        return;
-      }
-      window.open(this.driveEditURL, '_top');
-    });
+    const url = this.driveEditURL;
+    if (!url) return;
+    this._installExpanded = false;
+    navigateAndShowFallback(this, url);
+  },
+
+  _toggleInstall(e) {
+    e.preventDefault();
+    this._installExpanded = true;
+  },
+
+  _showError(message) {
+    this.$.toast.text = message;
+    this.$.toast.open();
   },
 
   get driveEditURL() {
diff --git a/addons/nuxeo-drive/elements/nuxeo-drive-upload-button.js b/addons/nuxeo-drive/elements/nuxeo-drive-upload-button.js
index e39e4ec9dd..9f2b479823 100644
--- a/addons/nuxeo-drive/elements/nuxeo-drive-upload-button.js
+++ b/addons/nuxeo-drive/elements/nuxeo-drive-upload-button.js
@@ -20,6 +20,7 @@ import { mixinBehaviors } from '@polymer/polymer/lib/legacy/class.js';
 import { I18nBehavior } from '@nuxeo/nuxeo-ui-elements/nuxeo-i18n-behavior.js';
 import { FiltersBehavior } from '@nuxeo/nuxeo-ui-elements/nuxeo-filters-behavior.js';
 import './nuxeo-drive-icons.js';
+import { base64UrlSafeEncode, navigateAndShowFallback } from './nuxeo-drive-utils.js';
 
 window.nuxeo = window.nuxeo || {};
 const baseUrl = window.nuxeo.baseUrl || window.location.origin + window.location.pathname;
@@ -40,6 +41,11 @@ class NuxeoDriveUploadButton extends mixinBehaviors([I18nBehavior, FiltersBehavi
         reflectToAttribute: true,
         value: false,
       },
+
+      _installExpanded: {
+        type: Boolean,
+        value: false,
+      },
     };
   }
 
@@ -47,10 +53,8 @@ class NuxeoDriveUploadButton extends mixinBehaviors([I18nBehavior, FiltersBehavi
     return html`
       <style include="nuxeo-action-button-styles"></style>
 
-      <nuxeo-resource id="token" path="/token" params='{"application": "Nuxeo Drive"}'></nuxeo-resource>
-
       <template is="dom-if" if="[[_isAvailable(document)]]">
-        <div class="action" on-tap="_go">
+        <div class="action" on-click="_go">
           <paper-icon-button
             noink
             icon="nuxeo-drive:transfer"
@@ -63,16 +67,63 @@ class NuxeoDriveUploadButton extends mixinBehaviors([I18nBehavior, FiltersBehavi
       </template>
 
       <nuxeo-dialog id="dialog" with-backdrop>
-        <div class="vertical layout">
-          <h1>[[i18n('driveEditButton.dialog.heading')]]</h1>
-          <nuxeo-drive-desktop-packages></nuxeo-drive-desktop-packages>
+        <style>
+          #dialog {
+            margin-top: 0;
+            top: 50%;
+            transform: translateY(-50%);
+            max-height: 80vh;
+          }
+
+          .dialog-content {
+            padding: 16px 24px;
+          }
+
+          .dialog-content h1 {
+            margin: 0 0 12px;
+            font-size: 1.6em;
+          }
+
+          .dialog-content p {
+            color: var(--primary-text-color, #333);
+            margin: 0 0 16px;
+          }
+
+          .close-btn {
+            border: 1px solid var(--nuxeo-primary-color, #0066ff);
+            color: var(--nuxeo-primary-color, #0066ff);
+            text-transform: uppercase;
+            font-size: 0.9em;
+            padding: 0.5em 1em;
+          }
+
+          .buttons {
+            justify-content: flex-end;
+          }
+
+          .install-link {
+            display: inline-block;
+            margin-top: 4px;
+            font-size: 0.9em;
+          }
+        </style>
+        <div class="dialog-content">
+          <h1>[[i18n('driveButton.dialog.heading')]]</h1>
+          <p>[[i18n('driveButton.dialog.description')]]</p>
+          <template is="dom-if" if="[[_installExpanded]]">
+            <p>[[i18n('driveButton.dialog.install.prompt')]]</p>
+            <nuxeo-drive-desktop-packages></nuxeo-drive-desktop-packages>
+          </template>
+          <template is="dom-if" if="[[!_installExpanded]]">
+            <a class="install-link" href="#" on-click="_toggleInstall">[[i18n('driveButton.install.dialog.hint')]]</a>
+          </template>
         </div>
         <div class="buttons">
-          <paper-button dialog-dismiss class="secondary">[[i18n('command.close')]]</paper-button>
+          <paper-button dialog-dismiss class="close-btn">[[i18n('command.close')]]</paper-button>
         </div>
       </nuxeo-dialog>
 
-      <paper-toast id="toast">[[i18n('driveUpload.directTransfer.failed')]]</paper-toast>
+      <paper-toast id="toast"></paper-toast>
     `;
   }
 
@@ -80,39 +131,54 @@ class NuxeoDriveUploadButton extends mixinBehaviors([I18nBehavior, FiltersBehavi
     if (!doc) return false;
 
     return (
-      this.hasPermission &&
-      this.hasFacet &&
-      this.isProxy &&
-      this.hasPermission(doc, 'Write') &&
-      this.hasFacet(doc, 'Folderish') &&
+      this.hasPermission?.(doc, 'Write') &&
+      this.hasFacet?.(doc, 'Folderish') &&
+      this.isProxy != null &&
       !this.isProxy(doc)
     );
   }
 
   _go() {
-    this.$.token
-      .get()
-      .then((response) => {
-        const tokens = response.entries.map((token) => token.id);
-        if (!tokens || !tokens.length) {
-          this.$.dialog.toggle();
-          return;
-        }
-        window.open(this.directTransferUrl, '_top');
-      })
-      .catch((error) => {
-        console.error('Token fetch failed:', error);
-        this.$.toast.toggle();
-      });
+    try {
+      this._installExpanded = false;
+      navigateAndShowFallback(this, this.directTransferUrl);
+    } catch (e) {
+      this._showError(e.message);
+    }
+  }
+
+  _toggleInstall(e) {
+    e.preventDefault();
+    this._installExpanded = true;
+  }
+
+  _showError(message) {
+    this.$.toast.text = message;
+    this.$.toast.open();
   }
 
   get directTransferUrl() {
-    const finalUrl = [
-      'nxdrive://direct-transfer',
-      baseUrl.split('/ui/')[0].replace('://', '/'),
-      this.document.path.slice(1),
-    ].join('/');
-    return finalUrl;
+    return this._compressUploadUrl();
+  }
+
+  _compressUploadUrl() {
+    const cleanBaseUrl = baseUrl.split('/ui/')[0].replace(/\/$/, '');
+    const isHttps = cleanBaseUrl.startsWith('https') ? 1 : 0;
+    const serverHost = cleanBaseUrl.replace('://', '/').split('/').slice(1).join('/');
+
+    const serverBytes = new TextEncoder().encode(serverHost);
+    if (serverBytes.length > 255) {
+      const msg = this.i18n('driveUpload.serverUrlTooLong');
+      this._showError(msg);
+      throw new Error(msg);
+    }
+
+    const docPath = this.document.path.startsWith('/') ? this.document.path.slice(1) : this.document.path;
+    const pathBytes = new TextEncoder().encode(docPath);
+
+    const payload = new Uint8Array([isHttps, serverBytes.length, ...serverBytes, ...pathBytes]);
+    const b64 = base64UrlSafeEncode(payload);
+    return `nxdrive://direct-transfer/${b64}`;
   }
 }
 
diff --git a/addons/nuxeo-drive/elements/nuxeo-drive-utils.js b/addons/nuxeo-drive/elements/nuxeo-drive-utils.js
new file mode 100644
index 0000000000..55f5c91f16
--- /dev/null
+++ b/addons/nuxeo-drive/elements/nuxeo-drive-utils.js
@@ -0,0 +1,71 @@
+/**
+©2023 Hyland Software, Inc. and its affiliates. All rights reserved.
+All Hyland product names are registered or unregistered trademarks of Hyland Software, Inc. or its affiliates.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+/**
+ * Shared utilities for nuxeo-drive action buttons.
+ *
+ * Centralises the token-fetch / dialog-toggle sequence and the URL-safe Base64
+ * encoder that are otherwise duplicated across nuxeo-drive-edit-button,
+ * nuxeo-drive-download-button, and nuxeo-drive-upload-button.
+ */
+
+/**
+ * Navigates to the given nxdrive:// URL and opens the install-help dialog.
+ *
+ * This follows the "navigate-first" pattern (like Zoom/Slack/Spotify):
+ * - The browser fires the custom protocol immediately; if Drive is installed
+ *   the OS shows a native "Open app?" prompt on top of the dialog.
+ * - The dialog stays visible behind the prompt with a subtle install hint,
+ *   so if Drive is *not* installed the user can expand the install links.
+ * - If Drive opened successfully the user simply closes the dialog.
+ *
+ * No detection hacks, timeouts, or environment-specific code.
+ *
+ * @param {Object} element  - The Polymer element instance (must expose $.dialog).
+ * @param {string} driveUrl - The nxdrive:// URL to navigate to.
+ */
+export function navigateAndShowFallback(element, driveUrl) {
+  // Navigate immediately — the browser / OS handles the custom protocol prompt.
+  // We use an anchor click instead of location.href to avoid a full page reload
+  // when the custom protocol is not registered (e.g. nxdrive:// on a machine
+  // without Nuxeo Drive).  Anchor clicks with unknown schemes are silently
+  // ignored by the browser rather than triggering a navigation error.
+  const a = document.createElement('a');
+  a.href = driveUrl;
+  a.click();
+
+  // Open the install-help dialog behind the browser's native prompt.
+  if (!element.$.dialog.opened) {
+    element.$.dialog.toggle();
+  }
+}
+
+/**
+ * Encodes a Uint8Array as a URL-safe Base64 string (no padding).
+ *
+ * @param {Uint8Array} bytes
+ * @returns {string}
+ */
+export function base64UrlSafeEncode(bytes) {
+  let binary = '';
+  bytes.forEach((byte) => {
+    binary += String.fromCodePoint(byte);
+  });
+  const b64 = btoa(binary).replaceAll('+', '-').replaceAll('/', '_');
+  const padStart = b64.indexOf('=');
+  return padStart === -1 ? b64 : b64.slice(0, padStart);
+}
diff --git a/addons/nuxeo-drive/test/nuxeo-drive-download-button.test.js b/addons/nuxeo-drive/test/nuxeo-drive-download-button.test.js
index f1d7aacf38..52f63bd637 100644
--- a/addons/nuxeo-drive/test/nuxeo-drive-download-button.test.js
+++ b/addons/nuxeo-drive/test/nuxeo-drive-download-button.test.js
@@ -18,20 +18,19 @@ limitations under the License.
 import { fixture, flush, html } from '@nuxeo/testing-helpers';
 import { PageProviderDisplayBehavior } from '@nuxeo/nuxeo-ui-elements/nuxeo-page-provider-display-behavior.js';
 import '../elements/nuxeo-drive-download-button.js';
+import { setupI18n, stubToast, addShowErrorSuite, addToggleInstallSuite } from './nuxeo-drive-test-helpers.test.js';
 
 // Setup i18n keys used by the component
-window.nuxeo = window.nuxeo || {};
-window.nuxeo.I18n = window.nuxeo.I18n || {};
-window.nuxeo.I18n.language = 'en';
-window.nuxeo.I18n.en = window.nuxeo.I18n.en || {};
-window.nuxeo.I18n.en['driveDownloadButton.tooltip'] = 'Download with Nuxeo Drive';
-window.nuxeo.I18n.en['driveDownload.noDocumentsSelected'] = 'No documents selected for download.';
-window.nuxeo.I18n.en['driveDownload.tooManyDocuments'] =
-  'You have selected more documents than supported. Please select up to {0} documents to download via Nuxeo Drive.';
-window.nuxeo.I18n.en['driveDownload.directTransfer.failed'] =
-  'An error occurred while trying to download the document with Nuxeo Drive.';
-window.nuxeo.I18n.en['driveEditButton.dialog.heading'] = 'Download Nuxeo Drive Client';
-window.nuxeo.I18n.en['command.close'] = 'Close';
+setupI18n({
+  'driveDownloadButton.tooltip': 'Download with Nuxeo Drive',
+  'driveDownload.noDocumentsSelected': 'No documents selected for download.',
+  'driveDownload.tooManyDocuments':
+    'You have selected more documents than supported. Please select up to {0} documents to download via Nuxeo Drive.',
+  'driveDownload.directTransfer.failed': 'An error occurred while trying to download the document with Nuxeo Drive.',
+  'driveButton.dialog.heading': 'Nuxeo Drive',
+  'driveButton.dialog.description': 'Use Nuxeo Drive to work with your documents directly from your desktop.',
+  'command.close': 'Close',
+});
 
 suite('nuxeo-drive-download-button', () => {
   let element;
@@ -40,6 +39,10 @@ suite('nuxeo-drive-download-button', () => {
     element = await fixture(html`<nuxeo-drive-download-button></nuxeo-drive-download-button>`);
   });
 
+  // Shared suites
+  addShowErrorSuite(() => element);
+  addToggleInstallSuite(() => element);
+
   // ---------------------------------------------------------------------------
   // _isAvailable
   // ---------------------------------------------------------------------------
@@ -88,14 +91,11 @@ suite('nuxeo-drive-download-button', () => {
       await flush();
       const actionDiv = element.shadowRoot.querySelector('.action');
       expect(actionDiv).to.exist;
-      // hidden$ binding: hidden attribute should NOT be set
       expect(actionDiv.hasAttribute('hidden')).to.be.false;
     });
 
     test('action div is hidden when _isAvailable returns false', async () => {
-      // Stub _isAvailable to return false (simulates select-all active)
       sinon.stub(element, '_isAvailable').returns(false);
-      // Re-trigger the binding by setting documents
       element.documents = [];
       await flush();
       const actionDiv = element.shadowRoot.querySelector('.action');
@@ -155,9 +155,7 @@ suite('nuxeo-drive-download-button', () => {
       expect(element._getSelectedDocumentUids()).to.deep.equal([]);
     });
 
-    test('returns UIDs from selectedItems (not items) when select-all is active and some items are deselected', () => {
-      // Simulates: select-all on 36 docs, then deselect 14 → 22 remain selected.
-      // selectAllActive stays true; selectedItems reflects the actual selection.
+    test('returns UIDs from selectedItems when select-all is active and some items are deselected', () => {
       const viewStub = {
         selectAllActive: true,
         behaviors: [...PageProviderDisplayBehavior],
@@ -180,7 +178,6 @@ suite('nuxeo-drive-download-button', () => {
         selectAllActive: true,
         behaviors: [...PageProviderDisplayBehavior],
         items: [{ uid: 'item-uid-1' }, { uid: 'item-uid-2' }],
-        // no selectedItems property
       };
       element.documents = viewStub;
       expect(element._getSelectedDocumentUids()).to.deep.equal(['item-uid-1', 'item-uid-2']);
@@ -208,6 +205,14 @@ suite('nuxeo-drive-download-button', () => {
       expect(url).to.include('00000000-0000-0000-0000-000000000001');
       expect(url).to.include('00000000-0000-0000-0000-000000000002');
     });
+
+    test('URL contains a server/host segment after the direct-download scheme', () => {
+      element.documents = [{ uid: '00000000-0000-0000-0000-000000000001' }];
+      const url = element._buildOriginalUrl();
+      const path = url.replace('nxdrive://direct-download/', '');
+      const segments = path.split('/');
+      expect(segments.length).to.be.at.least(2);
+    });
   });
 
   // ---------------------------------------------------------------------------
@@ -242,29 +247,11 @@ suite('nuxeo-drive-download-button', () => {
       element.documents = [{ uid: '00000000-1111-2222-3333-444444444444' }];
       expect(element.directDownloadUrl).to.match(/^nxdrive:\/\/direct-download\/[A-Za-z0-9_-]+$/);
     });
-  });
 
-  // ---------------------------------------------------------------------------
-  // _base64UrlSafeEncode
-  // ---------------------------------------------------------------------------
-  suite('_base64UrlSafeEncode', () => {
-    test('output contains no standard base64 padding (=)', () => {
-      const bytes = new Uint8Array([1, 2, 3, 4, 5]);
-      const result = element._base64UrlSafeEncode(bytes);
-      expect(result).to.not.include('=');
-    });
-
-    test('output contains no + characters (URL-safe)', () => {
-      // Use bytes that would produce '+' in standard base64
-      const bytes = new Uint8Array(Array.from({ length: 32 }, (_, i) => i + 200));
-      const result = element._base64UrlSafeEncode(bytes);
-      expect(result).to.not.include('+');
-    });
-
-    test('output contains no / characters (URL-safe)', () => {
-      const bytes = new Uint8Array(Array.from({ length: 32 }, (_, i) => i + 200));
-      const result = element._base64UrlSafeEncode(bytes);
-      expect(result).to.not.include('/');
+    test('throws when server host segment exceeds 255 bytes', () => {
+      const longServer = 'http/' + 'a'.repeat(260) + '/00000000-1111-2222-3333-444444444444';
+      const longUrl = `nxdrive://direct-download/${longServer}`;
+      expect(() => element._compressFromOriginalUrl(longUrl)).to.throw();
     });
   });
 
@@ -275,15 +262,14 @@ suite('nuxeo-drive-download-button', () => {
     let toastStub;
 
     setup(() => {
-      toastStub = { text: '', open: sinon.spy() };
-      sinon.stub(element.$, 'toast').value(toastStub);
+      toastStub = stubToast(element);
     });
 
     teardown(() => {
       sinon.restore();
     });
 
-    test('shows noDocumentsSelected error when documents is empty and document is unset', async () => {
+    test('shows noDocumentsSelected error when documents is empty and document is unset', () => {
       element.documents = [];
       element.document = null;
       element._download();
@@ -291,24 +277,6 @@ suite('nuxeo-drive-download-button', () => {
       expect(toastStub.text).to.include('No documents selected');
     });
 
-    test('triggers download for all items in view when select-all is active', async () => {
-      const viewStub = {
-        selectAllActive: true,
-        behaviors: [...PageProviderDisplayBehavior],
-        items: [{ uid: 'sa-uid-1' }, { uid: 'sa-uid-2' }, { uid: 'sa-uid-3' }],
-      };
-      element.documents = viewStub;
-      sinon.stub(element.$.token, 'get').resolves({ entries: [{ id: 'token-abc' }] });
-      const openStub = sinon.stub(window, 'open');
-
-      element._download();
-      await new Promise((resolve) => setTimeout(resolve, 0));
-
-      expect(toastStub.open).to.not.have.been.called;
-      expect(openStub).to.have.been.calledOnce;
-      expect(openStub.firstCall.args[1]).to.equal('_top');
-    });
-
     test('shows noDocumentsSelected error when select-all is active but view has no items', () => {
       const viewStub = {
         selectAllActive: true,
@@ -335,32 +303,7 @@ suite('nuxeo-drive-download-button', () => {
       expect(toastStub.text).to.include('25');
     });
 
-    test('succeeds after deselecting items so count drops to ≤ 25, even though selectAllActive stays true', async () => {
-      // Simulates the bug fix: select-all on 36 docs → deselect 13 → 23 selectedItems.
-      // selectAllActive remains true but selectedItems has only 23 entries.
-      const viewStub = {
-        selectAllActive: true,
-        behaviors: [...PageProviderDisplayBehavior],
-        items: Array.from({ length: 36 }, (_, i) => {
-          return { uid: `uid-${i}` };
-        }),
-        selectedItems: Array.from({ length: 23 }, (_, i) => {
-          return { uid: `uid-${i}` };
-        }),
-      };
-      element.documents = viewStub;
-      sinon.stub(element.$.token, 'get').resolves({ entries: [{ id: 'token-abc' }] });
-      const openStub = sinon.stub(window, 'open');
-
-      element._download();
-      await new Promise((resolve) => setTimeout(resolve, 0));
-
-      expect(toastStub.open).to.not.have.been.called;
-      expect(openStub).to.have.been.calledOnce;
-      expect(openStub.firstCall.args[1]).to.equal('_top');
-    });
-
-    test('shows tooManyDocuments error when more than 25 documents are selected', async () => {
+    test('shows tooManyDocuments error when more than 25 documents are selected', () => {
       element.documents = Array.from({ length: 26 }, (_, i) => {
         return { uid: `uid-${i}` };
       });
@@ -373,53 +316,34 @@ suite('nuxeo-drive-download-button', () => {
       element.documents = Array.from({ length: 25 }, (_, i) => {
         return { uid: `uid-${i}` };
       });
-      // Stub token.get to prevent real network call; stub window.open before _download is called
-      sinon.stub(element.$.token, 'get').returns(new Promise(() => {})); // never resolves — prevents window.open
       element._download();
-      // The toast should not have been opened at this point (no guard condition triggered)
       expect(toastStub.open).to.not.have.been.called;
     });
 
-    test('calls window.open with directDownloadUrl when a valid Drive token exists', async () => {
-      element.documents = [{ uid: 'doc-uid-1' }, { uid: 'doc-uid-2' }];
-      sinon.stub(element.$.token, 'get').resolves({ entries: [{ id: 'token-abc' }] });
-      const openStub = sinon.stub(window, 'open');
-
-      element._download();
-      // Let the promise chain resolve
-      await new Promise((resolve) => setTimeout(resolve, 0));
-
-      expect(openStub).to.have.been.calledOnce;
-      const calledUrl = openStub.firstCall.args[0];
-      expect(calledUrl).to.match(/^nxdrive:\/\/direct-download\/[A-Za-z0-9_-]+$/);
-      expect(openStub.firstCall.args[1]).to.equal('_top');
-    });
-
-    test('opens Drive install dialog when no Drive token is found', async () => {
-      element.documents = [{ uid: 'doc-uid-1' }];
-      sinon.stub(element.$.token, 'get').resolves({ entries: [] });
-      const dialogToggleStub = sinon.stub(element.$.dialog, 'toggle');
-
+    test('succeeds after deselecting items so count drops to ≤ 25', () => {
+      const viewStub = {
+        selectAllActive: true,
+        behaviors: [...PageProviderDisplayBehavior],
+        items: Array.from({ length: 36 }, (_, i) => {
+          return { uid: `uid-${i}` };
+        }),
+        selectedItems: Array.from({ length: 23 }, (_, i) => {
+          return { uid: `uid-${i}` };
+        }),
+      };
+      element.documents = viewStub;
       element._download();
-      await new Promise((resolve) => setTimeout(resolve, 0));
-
-      expect(dialogToggleStub).to.have.been.calledOnce;
       expect(toastStub.open).to.not.have.been.called;
     });
 
-    test('shows directTransfer.failed error when token.get rejects', async () => {
-      element.documents = [{ uid: 'doc-uid-1' }];
-      sinon.stub(element.$.token, 'get').rejects(new Error('network error'));
-
+    test('does not show error for a single document via document property', () => {
+      element.documents = [];
+      element.document = { uid: 'single-doc-uid' };
       element._download();
-      await new Promise((resolve) => setTimeout(resolve, 0));
-
-      expect(toastStub.open).to.have.been.calledOnce;
-      expect(toastStub.text).to.include('error occurred');
+      expect(toastStub.open).to.not.have.been.called;
     });
 
-    test('folder UID is collected as a single item (folder = one ID)', () => {
-      // Folders are treated as a single document ID — no enumeration of contents
+    test('folder UID is collected as a single item', () => {
       element.documents = [{ uid: 'folder-uid-1' }, { uid: 'folder-uid-2' }];
       const uids = element._getSelectedDocumentUids();
       expect(uids).to.deep.equal(['folder-uid-1', 'folder-uid-2']);
@@ -440,34 +364,33 @@ suite('nuxeo-drive-download-button', () => {
       expect(url).to.include('folder-uid-2');
     });
 
-    test('single document action (via document property) triggers download with correct UID', async () => {
-      element.documents = [];
-      element.document = { uid: 'single-doc-uid' };
-      sinon.stub(element.$.token, 'get').resolves({ entries: [{ id: 'token-abc' }] });
-      const openStub = sinon.stub(window, 'open');
-
+    test('triggers download for select-all items within limit', () => {
+      const viewStub = {
+        selectAllActive: true,
+        behaviors: [...PageProviderDisplayBehavior],
+        items: [{ uid: 'sa-uid-1' }, { uid: 'sa-uid-2' }, { uid: 'sa-uid-3' }],
+      };
+      element.documents = viewStub;
       element._download();
-      await new Promise((resolve) => setTimeout(resolve, 0));
+      expect(toastStub.open).to.not.have.been.called;
+    });
 
-      expect(openStub).to.have.been.calledOnce;
-      // Verify the UID is encoded in the compressed URL by checking the uncompressed URL
-      const originalUrl = element._buildOriginalUrl();
-      expect(originalUrl).to.include('single-doc-uid');
+    test('shows error with userMessage when _compressFromOriginalUrl throws with userMessage', () => {
+      element.documents = [{ uid: 'doc-uid-1' }];
+      const err = new Error('internal error');
+      err.userMessage = 'The server URL is too long';
+      sinon.stub(element, '_compressFromOriginalUrl').throws(err);
+      element._download();
+      expect(toastStub.open).to.have.been.calledOnce;
+      expect(toastStub.text).to.equal('The server URL is too long');
     });
-  });
 
-  // ---------------------------------------------------------------------------
-  // _buildOriginalUrl — server info
-  // ---------------------------------------------------------------------------
-  suite('_buildOriginalUrl — server info', () => {
-    test('URL contains a server/host segment after the direct-download scheme', () => {
-      element.documents = [{ uid: '00000000-0000-0000-0000-000000000001' }];
-      const url = element._buildOriginalUrl();
-      // Format: nxdrive://direct-download/<scheme>/<host>/.../<uid>
-      // After stripping the nxdrive://direct-download/ prefix there should be at least 2 more segments
-      const path = url.replace('nxdrive://direct-download/', '');
-      const segments = path.split('/');
-      expect(segments.length).to.be.at.least(2);
+    test('shows error with message when _compressFromOriginalUrl throws without userMessage', () => {
+      element.documents = [{ uid: 'doc-uid-1' }];
+      sinon.stub(element, '_compressFromOriginalUrl').throws(new Error('generic error'));
+      element._download();
+      expect(toastStub.open).to.have.been.calledOnce;
+      expect(toastStub.text).to.equal('generic error');
     });
   });
 });
diff --git a/addons/nuxeo-drive/test/nuxeo-drive-edit-button.test.js b/addons/nuxeo-drive/test/nuxeo-drive-edit-button.test.js
new file mode 100644
index 0000000000..739c53c782
--- /dev/null
+++ b/addons/nuxeo-drive/test/nuxeo-drive-edit-button.test.js
@@ -0,0 +1,131 @@
+/**
+@license
+©2023 Hyland Software, Inc. and its affiliates. All rights reserved.
+All Hyland product names are registered or unregistered trademarks of Hyland Software, Inc. or its affiliates.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+import { fixture, html } from '@nuxeo/testing-helpers';
+import '../elements/nuxeo-drive-edit-button.js';
+import { setupI18n, addShowErrorSuite, addToggleInstallSuite, addGoSuite } from './nuxeo-drive-test-helpers.test.js';
+
+// Setup i18n keys used by the component
+setupI18n({
+  'driveEditButton.tooltip': 'Open with Nuxeo Drive',
+  'driveEditButton.directTransfer.failed': 'An error occurred while trying to open the document with Nuxeo Drive.',
+  'driveEditButton.dialog.heading': 'Download Nuxeo Drive Client',
+  'driveButton.dialog.heading': 'Nuxeo Drive',
+  'driveButton.dialog.description': 'Use Nuxeo Drive to work with your documents directly from your desktop.',
+  'command.close': 'Close',
+});
+
+suite('nuxeo-drive-edit-button', () => {
+  let element;
+
+  setup(async () => {
+    element = await fixture(html`<nuxeo-drive-edit-button></nuxeo-drive-edit-button>`);
+    element.user = { id: 'Administrator' };
+    element.document = { uid: 'doc-uid-1', repository: 'default' };
+    element.blob = { data: 'http://localhost/nxfile/default/doc-uid-1/file:content/test.docx', name: 'test.docx' };
+  });
+
+  // Shared suites
+  addShowErrorSuite(() => element);
+  addToggleInstallSuite(() => element);
+  addGoSuite(() => element);
+
+  // ---------------------------------------------------------------------------
+  // _isAvailable — branch coverage
+  // ---------------------------------------------------------------------------
+  suite('_isAvailable', () => {
+    const baseDoc = () => {
+      return {
+        uid: 'doc-1',
+        facets: [],
+        contextParameters: { permissions: ['Write', 'Read'] },
+      };
+    };
+
+    const blobWithNoAppLinks = { data: 'http://localhost/nxfile/default/doc-1/file:content/test.docx', appLinks: [] };
+
+    test('returns false when blob is null', () => {
+      expect(element._isAvailable(baseDoc(), null)).to.not.be.ok;
+    });
+
+    test('returns false when blob is undefined', () => {
+      expect(element._isAvailable(baseDoc(), undefined)).to.not.be.ok;
+    });
+
+    test('returns false when blob.appLinks is non-empty', () => {
+      const blobWithLinks = { ...blobWithNoAppLinks, appLinks: [{ name: 'SomeApp', url: 'someapp://open' }] };
+      expect(element._isAvailable(baseDoc(), blobWithLinks)).to.be.false;
+    });
+
+    test('returns false when doc lacks Write permission', () => {
+      const doc = { uid: 'doc-1', facets: [], contextParameters: { permissions: ['Read'] } };
+      expect(element._isAvailable(doc, blobWithNoAppLinks)).to.be.false;
+    });
+
+    test('returns false when doc is a proxy', () => {
+      const doc = {
+        uid: 'doc-1',
+        facets: ['Immutable', 'HiddenInNavigation'],
+        isProxy: true,
+        contextParameters: { permissions: ['Write'] },
+      };
+      expect(element._isAvailable(doc, blobWithNoAppLinks)).to.be.false;
+    });
+
+    test('returns true when blob has no appLinks property at all', () => {
+      const blobNoAppLinksKey = { data: 'http://localhost/nxfile/default/doc-1/file:content/test.docx' };
+      expect(element._isAvailable(baseDoc(), blobNoAppLinksKey)).to.be.true;
+    });
+
+    test('returns true when all conditions are met', () => {
+      expect(element._isAvailable(baseDoc(), blobWithNoAppLinks)).to.be.true;
+    });
+  });
+
+  // ---------------------------------------------------------------------------
+  // driveEditURL
+  // ---------------------------------------------------------------------------
+  suite('driveEditURL', () => {
+    test('returns empty string when blob is not set', () => {
+      element.blob = null;
+      expect(element.driveEditURL).to.equal('');
+    });
+
+    test('returns empty string when blob is undefined', () => {
+      element.blob = undefined;
+      expect(element.driveEditURL).to.equal('');
+    });
+
+    test('builds a valid nxdrive://edit URL from blob data', () => {
+      const url = element.driveEditURL;
+      expect(url).to.match(/^nxdrive:\/\/edit\//);
+      expect(url).to.include('Administrator');
+      expect(url).to.include('doc-uid-1');
+      expect(url).to.include('default');
+      expect(url).to.include('test.docx');
+    });
+
+    test('encodes the filename in the URL', () => {
+      element.blob = {
+        data: 'http://localhost/nxfile/default/doc-uid-1/file:content/my%20doc.docx',
+        name: 'my doc.docx',
+      };
+      const url = element.driveEditURL;
+      expect(url).to.include(encodeURIComponent('my doc.docx'));
+    });
+  });
+});
diff --git a/addons/nuxeo-drive/test/nuxeo-drive-test-helpers.test.js b/addons/nuxeo-drive/test/nuxeo-drive-test-helpers.test.js
new file mode 100644
index 0000000000..113ca820f3
--- /dev/null
+++ b/addons/nuxeo-drive/test/nuxeo-drive-test-helpers.test.js
@@ -0,0 +1,168 @@
+/**
+@license
+©2023 Hyland Software, Inc. and its affiliates. All rights reserved.
+All Hyland product names are registered or unregistered trademarks of Hyland Software, Inc. or its affiliates.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+/**
+ * Shared helpers for nuxeo-drive unit tests.
+ *
+ * Centralises repeated patterns (i18n setup, stub factories, async helpers, and
+ * common test-suite factories) so individual test files stay free of duplication.
+ */
+
+// Prevent nxdrive:// anchor clicks from triggering a Karma page reload.
+// navigateAndShowFallback() creates an anchor and clicks it; this no-op
+// stops the browser from actually following the custom-protocol link.
+HTMLAnchorElement.prototype.click = function () {};
+
+// ---------------------------------------------------------------------------
+// i18n bootstrap
+// ---------------------------------------------------------------------------
+
+/**
+ * Initialises the minimum globalThis.nuxeo.I18n structure required by
+ * nuxeo-drive components and merges the supplied key map.
+ *
+ * @param {Object} keys  - Map of i18n key → English value.
+ */
+export function setupI18n(keys) {
+  globalThis.nuxeo = globalThis.nuxeo || {};
+  globalThis.nuxeo.I18n = globalThis.nuxeo.I18n || {};
+  globalThis.nuxeo.I18n.language = 'en';
+  globalThis.nuxeo.I18n.en = globalThis.nuxeo.I18n.en || {};
+  Object.assign(globalThis.nuxeo.I18n.en, keys);
+}
+
+// ---------------------------------------------------------------------------
+// Async helpers
+// ---------------------------------------------------------------------------
+
+/** Flushes the microtask queue (one event-loop turn). */
+export function nextTick() {
+  return new Promise((resolve) => setTimeout(resolve, 0));
+}
+
+// ---------------------------------------------------------------------------
+// Common stub factories
+// ---------------------------------------------------------------------------
+
+/**
+ * Stubs `element.$.toast` with a spy-equipped object and returns it.
+ *
+ * @param {Object} element  - Polymer element under test.
+ * @returns {{ text: string, open: sinon.SinonSpy }}
+ */
+export function stubToast(element) {
+  const toastStub = { text: '', open: sinon.spy() };
+  sinon.stub(element.$, 'toast').value(toastStub);
+  return toastStub;
+}
+
+// ---------------------------------------------------------------------------
+// Shared test-suite factories
+// ---------------------------------------------------------------------------
+
+/**
+ * Registers the canonical `_showError` test suite against an element getter.
+ *
+ * @param {Function} getElement  - Returns the element under test (called inside each test).
+ */
+export function addShowErrorSuite(getElement) {
+  suite('_showError', () => {
+    teardown(() => sinon.restore());
+
+    test('sets toast text and opens it', () => {
+      const element = getElement();
+      const toastStub = stubToast(element);
+      element._showError('Something went wrong');
+      expect(toastStub.text).to.equal('Something went wrong');
+      expect(toastStub.open).to.have.been.calledOnce;
+    });
+  });
+}
+
+/**
+ * Registers canonical `_toggleInstall` test suite against an element getter.
+ *
+ * @param {Function} getElement  - Returns the element under test.
+ */
+export function addToggleInstallSuite(getElement) {
+  suite('_toggleInstall', () => {
+    test('sets _installExpanded to true', () => {
+      const element = getElement();
+      const fakeEvent = { preventDefault: sinon.spy() };
+      element._toggleInstall(fakeEvent);
+      expect(element._installExpanded).to.be.true;
+    });
+
+    test('calls event.preventDefault()', () => {
+      const element = getElement();
+      const fakeEvent = { preventDefault: sinon.spy() };
+      element._toggleInstall(fakeEvent);
+      expect(fakeEvent.preventDefault).to.have.been.calledOnce;
+    });
+  });
+}
+
+/**
+ * Registers a test suite for the navigate-first `_go` method pattern.
+ *
+ * Covers: dialog opening, _installExpanded reset, and re-entry guard.
+ *
+ * Stubs the element's `_navigate` method (if it exists) to prevent actual navigation
+ * and ensure test isolation. If the element doesn't expose `_navigate`, the stub is skipped.
+ *
+ * @param {Function} getElement  - Returns the element under test.
+ * @param {string}   goMethod   - Name of the go method (e.g. '_go' or '_download').
+ */
+export function addGoSuite(getElement, goMethod = '_go') {
+  suite(`${goMethod} — navigate-first pattern`, () => {
+    setup(() => {
+      const element = getElement();
+      element.$.dialog.toggle = element.$.dialog.toggle || function () {};
+      // Stub _navigate if it exists to prevent actual globalThis.location assignment.
+      // This ensures each test is isolated and not dependent on test execution order.
+      if (typeof element._navigate === 'function') {
+        sinon.stub(element, '_navigate');
+      }
+    });
+
+    teardown(() => sinon.restore());
+
+    test('opens the dialog', () => {
+      const element = getElement();
+      const dialogToggleStub = sinon.stub(element.$.dialog, 'toggle');
+      element[goMethod]();
+      expect(dialogToggleStub).to.have.been.calledOnce;
+    });
+
+    test('resets _installExpanded to false', () => {
+      const element = getElement();
+      sinon.stub(element.$.dialog, 'toggle');
+      element._installExpanded = true;
+      element[goMethod]();
+      expect(element._installExpanded).to.be.false;
+    });
+
+    test('does not re-open the dialog when it is already open', () => {
+      const element = getElement();
+      element.$.dialog.opened = true;
+      const dialogToggleStub = sinon.stub(element.$.dialog, 'toggle');
+      element[goMethod]();
+      expect(dialogToggleStub).to.not.have.been.called;
+    });
+  });
+}
diff --git a/addons/nuxeo-drive/test/nuxeo-drive-upload-button.test.js b/addons/nuxeo-drive/test/nuxeo-drive-upload-button.test.js
new file mode 100644
index 0000000000..85be719a26
--- /dev/null
+++ b/addons/nuxeo-drive/test/nuxeo-drive-upload-button.test.js
@@ -0,0 +1,165 @@
+/**
+@license
+©2023 Hyland Software, Inc. and its affiliates. All rights reserved.
+All Hyland product names are registered or unregistered trademarks of Hyland Software, Inc. or its affiliates.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+import { fixture, html } from '@nuxeo/testing-helpers';
+import '../elements/nuxeo-drive-upload-button.js';
+import { base64UrlSafeEncode } from '../elements/nuxeo-drive-utils.js';
+import {
+  setupI18n,
+  stubToast,
+  addShowErrorSuite,
+  addToggleInstallSuite,
+  addGoSuite,
+} from './nuxeo-drive-test-helpers.test.js';
+
+// Setup i18n keys used by the component
+setupI18n({
+  'driveUploadButton.tooltip': 'Upload with Nuxeo Drive',
+  'driveUpload.directTransfer.failed': 'An error occurred while trying to upload the document with Nuxeo Drive.',
+  'driveUpload.serverUrlTooLong': 'Server URL is too long to encode.',
+  'driveButton.dialog.heading': 'Nuxeo Drive',
+  'driveButton.dialog.description': 'Use Nuxeo Drive to work with your documents directly from your desktop.',
+  'command.close': 'Close',
+});
+
+suite('nuxeo-drive-upload-button', () => {
+  let element;
+
+  setup(async () => {
+    element = await fixture(html`<nuxeo-drive-upload-button></nuxeo-drive-upload-button>`);
+    element.document = { path: '/default-domain/workspaces/test-folder' };
+  });
+
+  // Shared suites
+  addShowErrorSuite(() => element);
+  addToggleInstallSuite(() => element);
+  addGoSuite(() => element);
+
+  // ---------------------------------------------------------------------------
+  // _isAvailable
+  // ---------------------------------------------------------------------------
+  suite('_isAvailable', () => {
+    test('returns false when doc is null', () => {
+      expect(element._isAvailable(null)).to.be.false;
+    });
+
+    test('returns false when doc is undefined', () => {
+      expect(element._isAvailable(undefined)).to.be.false;
+    });
+  });
+
+  // ---------------------------------------------------------------------------
+  // _go — error path
+  // ---------------------------------------------------------------------------
+  suite('_go — error handling', () => {
+    teardown(() => sinon.restore());
+
+    test('shows error when _compressUploadUrl throws', () => {
+      const toastStub = stubToast(element);
+      sinon.stub(element, '_compressUploadUrl').throws(new Error('compression failed'));
+      element._go();
+      expect(toastStub.text).to.equal('compression failed');
+      expect(toastStub.open).to.have.been.calledOnce;
+    });
+  });
+
+  // ---------------------------------------------------------------------------
+  // _compressUploadUrl / directTransferUrl
+  // ---------------------------------------------------------------------------
+  suite('_compressUploadUrl', () => {
+    test('returns a nxdrive://direct-transfer/<base64> URL', () => {
+      const compressed = element._compressUploadUrl();
+      expect(compressed).to.match(/^nxdrive:\/\/direct-transfer\/[A-Za-z0-9_-]+$/);
+    });
+
+    test('compressed URL does not contain the raw document path', () => {
+      const compressed = element._compressUploadUrl();
+      expect(compressed).to.not.include('default-domain');
+      expect(compressed).to.not.include('workspaces');
+    });
+
+    test('different document paths produce different compressed URLs', () => {
+      element.document = { path: '/default-domain/workspaces/folder-a' };
+      const url1 = element._compressUploadUrl();
+      element.document = { path: '/default-domain/workspaces/folder-b' };
+      const url2 = element._compressUploadUrl();
+      expect(url1).to.not.equal(url2);
+    });
+
+    test('handles path with leading slash correctly', () => {
+      element.document = { path: '/default-domain/workspaces/my-folder' };
+      const url = element._compressUploadUrl();
+      expect(url).to.match(/^nxdrive:\/\/direct-transfer\/[A-Za-z0-9_-]+$/);
+    });
+
+    test('handles path without leading slash correctly', () => {
+      element.document = { path: 'default-domain/workspaces/my-folder' };
+      const url = element._compressUploadUrl();
+      expect(url).to.match(/^nxdrive:\/\/direct-transfer\/[A-Za-z0-9_-]+$/);
+    });
+
+    test('directTransferUrl getter delegates to _compressUploadUrl', () => {
+      const compressSpy = sinon.spy(element, '_compressUploadUrl');
+      const url = element.directTransferUrl;
+      expect(compressSpy).to.have.been.calledOnce;
+      expect(url).to.match(/^nxdrive:\/\/direct-transfer\/[A-Za-z0-9_-]+$/);
+      sinon.restore();
+    });
+
+    test('shows error and throws when server bytes exceed 255', () => {
+      const toastStub = stubToast(element);
+      const origEncode = TextEncoder.prototype.encode;
+      let callCount = 0;
+      sinon.stub(TextEncoder.prototype, 'encode').callsFake(function (str) {
+        callCount++;
+        if (callCount === 1) {
+          return new Uint8Array(256);
+        }
+        return origEncode.call(this, str);
+      });
+
+      element.document = { path: '/some/path' };
+      expect(() => element._compressUploadUrl()).to.throw();
+      expect(toastStub.open).to.have.been.calledOnce;
+
+      sinon.restore();
+    });
+  });
+
+  // ---------------------------------------------------------------------------
+  // base64UrlSafeEncode
+  // ---------------------------------------------------------------------------
+  suite('base64UrlSafeEncode', () => {
+    test('output contains no standard base64 padding (=)', () => {
+      const bytes = new Uint8Array([1, 2, 3, 4, 5]);
+      const result = base64UrlSafeEncode(bytes);
+      expect(result).to.not.include('=');
+    });
+
+    test('output contains no + characters (URL-safe)', () => {
+      const bytes = new Uint8Array(Array.from({ length: 32 }, (_, i) => i + 200));
+      const result = base64UrlSafeEncode(bytes);
+      expect(result).to.not.include('+');
+    });
+
+    test('output contains no / characters (URL-safe)', () => {
+      const bytes = new Uint8Array(Array.from({ length: 32 }, (_, i) => i + 200));
+      const result = base64UrlSafeEncode(bytes);
+      expect(result).to.not.include('/');
+    });
+  });
+});
diff --git a/i18n/messages.json b/i18n/messages.json
index f53dcf0f83..327ba1db2d 100644
--- a/i18n/messages.json
+++ b/i18n/messages.json
@@ -506,6 +506,11 @@
   "bulkDownload.filename.selection": "selection",
   "bulkDownload.preparing": "Preparing Zip export.",
   "bulkDownload.tooltip": "Download All as Zip",
+  "driveButton.dialog.description": "Use Nuxeo Drive to work with your documents directly from your desktop.",
+  "driveButton.dialog.heading": "Nuxeo Drive",
+  "driveButton.dialog.install.hint": "If Nuxeo Drive didn't open, it may not be installed on this computer.",
+  "driveButton.dialog.install.prompt": "Download and install Nuxeo Drive for your platform:",
+  "driveButton.install.dialog.hint": "Nuxeo Drive didn\u0027t open? Click here to download and install it.",
   "driveDesktopPackages.install": "Package to Install",
   "driveDesktopPackages.platform": "Platform",
   "driveDownload.directTransfer.failed": "An error occurred while trying to download the document with Nuxeo Drive.",
@@ -514,9 +519,8 @@
   "driveDownload.tooManyDocuments": "You have selected more documents than supported. Please select up to {0} documents to download via Nuxeo Drive.",
   "driveDownloadButton.tooltip": "Download with Nuxeo Drive",
   "driveEditButton.dialog.heading": "Download Nuxeo Drive Client",
+  "driveEditButton.directTransfer.failed": "An error occurred while trying to open the document with Nuxeo Drive.",
   "driveEditButton.tooltip": "Open with Nuxeo Drive",
-  "driveUpload.directTransfer.failed": "An error occurred while trying to upload the document with Nuxeo Drive.",
-  "driveUploadButton.tooltip": "Upload with Nuxeo Drive",
   "drivePage.heading": "Nuxeo Drive",
   "drivePage.packages": "Packages",
   "drivePage.roots": "Synchronization Roots",
@@ -528,6 +532,9 @@
   "driveSyncRootsManagement.roots.empty": "You currently don't have any synchronization roots.",
   "driveSyncToggleButton.sync": "Synchronize",
   "driveSyncToggleButton.unsync": "Unsynchronize",
+  "driveUpload.directTransfer.failed": "An error occurred while trying to upload the document with Nuxeo Drive.",
+  "driveUpload.serverUrlTooLong": "The server URL is too long to generate a Nuxeo Drive upload link.",
+  "driveUploadButton.tooltip": "Upload with Nuxeo Drive",
   "dropzone.abort": "Abort file upload",
   "dropzone.add": "Upload main file",
   "dropzone.invalid.error": "Invalid content",
@@ -1539,4 +1546,4 @@
   "workflowAnalytics.averageTaskDurationPerUser.user": "User",
   "workflowAnalytics.averageWorkflowDuration.heading": "Average Workflow Duration",
   "workflowAnalytics.workflowInitiators.heading": "Workflow Initiators"
-}
+}
\ No newline at end of file