diff --git a/components/calendar/event-card.tsx b/components/calendar/event-card.tsx
index 7948da6..d365dec 100644
--- a/components/calendar/event-card.tsx
+++ b/components/calendar/event-card.tsx
@@ -28,7 +28,8 @@ function getEventColor(event: CalendarEvent, calendar?: Calendar): string {
   return sanitizeColor(event.color, sanitizeColor(calendar?.color));
 }
 
-function parseDuration(duration: string): number {
+function parseDuration(duration: string | undefined): number {
+  if (!duration) return 0;
   let totalMinutes = 0;
   const weekMatch = duration.match(/(\d+)W/);
   const hourMatch = duration.match(/(\d+)H/);
diff --git a/lib/jmap/client.ts b/lib/jmap/client.ts
index f96e976..ee04300 100644
--- a/lib/jmap/client.ts
+++ b/lib/jmap/client.ts
@@ -1433,17 +1433,22 @@ export class JMAPClient {
     throw new Error('Invalid upload response: blobId not found');
   }
 
-  async createSieveScript(name: string, content: string): Promise<SieveScript> {
+  async createSieveScript(name: string, content: string, activate?: boolean): Promise<SieveScript> {
     const blobId = await this.uploadSieveBlob(content);
     const accountId = this.getSieveAccountId();
 
+    const setArgs: Record<string, unknown> = {
+      accountId,
+      create: {
+        "new-script": { name, blobId }
+      },
+    };
+    if (activate) {
+      setArgs.onSuccessActivateScript = "#new-script";
+    }
+
     const response = await this.request([
-      ["SieveScript/set", {
-        accountId,
-        create: {
-          "new-script": { name, blobId }
-        }
-      }, "0"]
+      ["SieveScript/set", setArgs, "0"]
     ], this.sieveUsing());
 
     if (response.methodResponses?.[0]?.[0] === "SieveScript/set") {
@@ -1462,17 +1467,22 @@ export class JMAPClient {
     throw new Error("Failed to create sieve script");
   }
 
-  async updateSieveScript(scriptId: string, content: string): Promise<void> {
+  async updateSieveScript(scriptId: string, content: string, activate?: boolean): Promise<void> {
     const blobId = await this.uploadSieveBlob(content);
     const accountId = this.getSieveAccountId();
 
+    const setArgs: Record<string, unknown> = {
+      accountId,
+      update: {
+        [scriptId]: { blobId }
+      },
+    };
+    if (activate) {
+      setArgs.onSuccessActivateScript = scriptId;
+    }
+
     const response = await this.request([
-      ["SieveScript/set", {
-        accountId,
-        update: {
-          [scriptId]: { blobId }
-        }
-      }, "0"]
+      ["SieveScript/set", setArgs, "0"]
     ], this.sieveUsing());
 
     if (response.methodResponses?.[0]?.[0] === "SieveScript/set") {
@@ -1513,44 +1523,36 @@ export class JMAPClient {
     const response = await this.request([
       ["SieveScript/set", {
         accountId,
-        update: {
-          [scriptId]: { isActive: true }
-        }
+        onSuccessActivateScript: scriptId,
       }, "0"]
     ], this.sieveUsing());
 
-    if (response.methodResponses?.[0]?.[0] === "SieveScript/set") {
-      const result = response.methodResponses[0][1];
-      if (result.notUpdated?.[scriptId]) {
-        const error = result.notUpdated[scriptId];
-        throw new Error(error.description || "Failed to activate sieve script");
-      }
-      return;
+    const [methodName, result] = response.methodResponses?.[0] || [];
+    if (methodName === "error") {
+      throw new Error(result?.description || "Failed to activate sieve script");
+    }
+    if (methodName !== "SieveScript/set") {
+      throw new Error("Failed to activate sieve script");
     }
-    throw new Error("Failed to activate sieve script");
   }
 
-  async deactivateSieveScript(scriptId: string): Promise<void> {
+  async deactivateSieveScript(): Promise<void> {
     const accountId = this.getSieveAccountId();
 
     const response = await this.request([
       ["SieveScript/set", {
         accountId,
-        update: {
-          [scriptId]: { isActive: false }
-        }
+        onSuccessActivateScript: null,
       }, "0"]
     ], this.sieveUsing());
 
-    if (response.methodResponses?.[0]?.[0] === "SieveScript/set") {
-      const result = response.methodResponses[0][1];
-      if (result.notUpdated?.[scriptId]) {
-        const error = result.notUpdated[scriptId];
-        throw new Error(error.description || "Failed to deactivate sieve script");
-      }
-      return;
+    const [methodName, result] = response.methodResponses?.[0] || [];
+    if (methodName === "error") {
+      throw new Error(result?.description || "Failed to deactivate sieve script");
+    }
+    if (methodName !== "SieveScript/set") {
+      throw new Error("Failed to deactivate sieve script");
     }
-    throw new Error("Failed to deactivate sieve script");
   }
 
   async validateSieveScript(content: string): Promise<{ isValid: boolean; errors?: string[] }> {
diff --git a/lib/jmap/types.ts b/lib/jmap/types.ts
index 7cf0908..f2194aa 100644
--- a/lib/jmap/types.ts
+++ b/lib/jmap/types.ts
@@ -312,7 +312,7 @@ export interface CalendarEvent {
   updated: string;
   sequence: number;
   start: string;
-  duration: string;
+  duration?: string;
   timeZone: string | null;
   showWithoutTime: boolean;
   status: 'tentative' | 'confirmed' | 'cancelled';
diff --git a/stores/filter-store.ts b/stores/filter-store.ts
index a5bc40d..25f2aaa 100644
--- a/stores/filter-store.ts
+++ b/stores/filter-store.ts
@@ -94,11 +94,9 @@ export const useFilterStore = create<FilterStore>()((set, get) => ({
       }
 
       if (activeScriptId) {
-        await client.updateSieveScript(activeScriptId, content);
-        await client.activateSieveScript(activeScriptId);
+        await client.updateSieveScript(activeScriptId, content, true);
       } else {
-        const script = await client.createSieveScript('filters', content);
-        await client.activateSieveScript(script.id);
+        const script = await client.createSieveScript('filters', content, true);
         set({ activeScriptId: script.id });
       }