diff --git a/src/Tasks.ts b/src/Tasks.ts
index a1cf5f9..e7d98e6 100644
--- a/src/Tasks.ts
+++ b/src/Tasks.ts
@@ -93,6 +93,37 @@ export class TaskActions {
     return taskList.map((task) => this.formatTask(task)).join("\n");
   }
 
+  // Normalize date strings to RFC3339 format required by Google Tasks API
+  private static normalizeDate(dateStr: string | undefined): string | undefined {
+    if (!dateStr) return undefined;
+
+    // Already has timezone (ends with Z or +/-offset)
+    if (/Z$|[+-]\d{2}:\d{2}$/.test(dateStr)) {
+      return dateStr;
+    }
+
+    // Date only (YYYY-MM-DD) - add time and Z
+    if (/^\d{4}-\d{2}-\d{2}$/.test(dateStr)) {
+      return `${dateStr}T00:00:00.000Z`;
+    }
+
+    // DateTime without timezone - add Z
+    if (/^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}/.test(dateStr)) {
+      // Remove any milliseconds and add Z
+      const base = dateStr.replace(/\.\d+$/, '');
+      return `${base}.000Z`;
+    }
+
+    // Try to parse and convert
+    const date = new Date(dateStr);
+    if (!isNaN(date.getTime())) {
+      return date.toISOString();
+    }
+
+    // Return as-is if we can't parse (let API handle the error)
+    return dateStr;
+  }
+
   private static async _list(request: CallToolRequest, tasks: tasks_v1.Tasks) {
     const taskListsResponse = await tasks.tasklists.list({
       maxResults: MAX_TASK_RESULTS,
@@ -134,7 +165,7 @@ export class TaskActions {
     const task = {
       title: taskTitle,
       notes: taskNotes,
-      due: taskDue,
+      due: this.normalizeDate(taskDue),
     };
 
     const taskResponse = await tasks.tasks.insert({
@@ -176,7 +207,7 @@ export class TaskActions {
       title: taskTitle,
       notes: taskNotes,
       status: taskStatus,
-      due: taskDue,
+      due: this.normalizeDate(taskDue),
     };
 
     const taskResponse = await tasks.tasks.update({
diff --git a/src/index.ts b/src/index.ts
index 0118656..41c67f9 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -13,6 +13,7 @@ import {
 import fs from "fs";
 import { google, tasks_v1 } from "googleapis";
 import path from "path";
+import { fileURLToPath } from "url";
 import { TaskActions, TaskResources } from "./Tasks.js";
 
 const tasks = google.tasks("v1");
@@ -201,6 +202,14 @@ server.setRequestHandler(ListToolsRequestSchema, async () => {
           required: ["id", "uri"],
         },
       },
+      {
+        name: "list-tasklists",
+        description: "List all task lists in Google Tasks",
+        inputSchema: {
+          type: "object",
+          properties: {},
+        },
+      },
     ],
   };
 });
@@ -230,18 +239,35 @@ server.setRequestHandler(CallToolRequestSchema, async (request) => {
     const taskResult = await TaskActions.clear(request, tasks);
     return taskResult;
   }
+  if (request.params.name === "list-tasklists") {
+    const response = await tasks.tasklists.list();
+    const taskLists = response.data.items || [];
+    const formatted = taskLists.map((list) =>
+      `${list.title} (ID: ${list.id})`
+    ).join("\n");
+    return {
+      content: [
+        {
+          type: "text",
+          text: taskLists.length > 0
+            ? `Found ${taskLists.length} task lists:\n${formatted}`
+            : "No task lists found",
+        },
+      ],
+    };
+  }
   throw new Error("Tool not found");
 });
 
 const credentialsPath = path.join(
-  path.dirname(new URL(import.meta.url).pathname),
+  path.dirname(fileURLToPath(import.meta.url)),
   "../.gtasks-server-credentials.json",
 );
 
 async function authenticateAndSaveCredentials() {
   console.log("Launching auth flow…");
   const p = path.join(
-    path.dirname(new URL(import.meta.url).pathname),
+    path.dirname(fileURLToPath(import.meta.url)),
     "../gcp-oauth.keys.json",
   );
 
@@ -263,8 +289,23 @@ async function loadCredentialsAndRunServer() {
   }
 
   const credentials = JSON.parse(fs.readFileSync(credentialsPath, "utf-8"));
-  const auth = new google.auth.OAuth2();
+
+  // Load OAuth app credentials to enable token refresh
+  // Support GOOGLE_OAUTH_CREDENTIALS env var for shared credential location
+  const oauthKeysPath = process.env.GOOGLE_OAUTH_CREDENTIALS ||
+    path.join(path.dirname(credentialsPath), "gcp-oauth.keys.json");
+  const oauthKeys = JSON.parse(fs.readFileSync(oauthKeysPath, "utf-8"));
+  const { client_id, client_secret } = oauthKeys.installed;
+
+  const auth = new google.auth.OAuth2(client_id, client_secret);
   auth.setCredentials(credentials);
+
+  // Auto-save refreshed tokens
+  auth.on('tokens', (tokens) => {
+    const updated = { ...credentials, ...tokens };
+    fs.writeFileSync(credentialsPath, JSON.stringify(updated, null, 2));
+  });
+
   google.options({ auth });
 
   const transport = new StdioServerTransport();