diff --git a/apps/sim/lib/copilot/request/session/buffer.test.ts b/apps/sim/lib/copilot/request/session/buffer.test.ts
index 951cdbc648d..6aa9bc0752a 100644
--- a/apps/sim/lib/copilot/request/session/buffer.test.ts
+++ b/apps/sim/lib/copilot/request/session/buffer.test.ts
@@ -149,7 +149,7 @@ describe('mothership-stream-outbox', () => {
     expect(replayed.map((entry) => entry.payload.text)).toEqual(['world'])
   })
 
-  it('does not trim active stream history while appending events', async () => {
+  it('trims active stream history to eventLimit on every append', async () => {
     const cursor = await allocateCursor('stream-1')
 
     await appendEvent(
@@ -163,7 +163,11 @@ describe('mothership-stream-outbox', () => {
       })
     )
 
-    expect(mockRedis.zremrangebyrank).not.toHaveBeenCalled()
+    expect(mockRedis.zremrangebyrank).toHaveBeenCalledWith(
+      'mothership_stream:stream-1:events',
+      0,
+      -5_001
+    )
   })
 
   it('clears persisted stream state during teardown cleanup', async () => {
diff --git a/apps/sim/lib/copilot/request/session/buffer.ts b/apps/sim/lib/copilot/request/session/buffer.ts
index 6ee42bedc97..810b0cd5a88 100644
--- a/apps/sim/lib/copilot/request/session/buffer.ts
+++ b/apps/sim/lib/copilot/request/session/buffer.ts
@@ -144,6 +144,7 @@ export async function appendEvents(
       zaddArgs.push(envelope.seq, JSON.stringify(envelope))
     }
     pipeline.zadd(key, ...(zaddArgs as [number, string, ...Array<number | string>]))
+    pipeline.zremrangebyrank(key, 0, -config.eventLimit - 1)
     pipeline.expire(key, config.ttlSeconds)
     pipeline.set(seqKey, String(envelopes[envelopes.length - 1].seq), 'EX', config.ttlSeconds)
     await pipeline.exec()
diff --git a/apps/sim/lib/core/idempotency/service.ts b/apps/sim/lib/core/idempotency/service.ts
index b5428075a07..c4a0e9f25fb 100644
--- a/apps/sim/lib/core/idempotency/service.ts
+++ b/apps/sim/lib/core/idempotency/service.ts
@@ -16,6 +16,14 @@ export interface IdempotencyConfig {
   namespace?: string
   /** When true, failed keys are deleted rather than stored so the operation is retried on the next attempt. */
   retryFailures?: boolean
+  /**
+   * When false, only `{ success, status, error? }` is persisted — not the
+   * operation's return value. Duplicate calls still short-circuit but
+   * resolve to `undefined`. Use when callers don't consume the cached
+   * body (e.g. webhook receivers, where the provider just wants a 2xx).
+   * Defaults to true.
+   */
+  storeResultBody?: boolean
   /**
    * Force a specific storage backend regardless of the environment's
    * auto-detection. Use `'database'` for correctness-critical flows
@@ -77,6 +85,7 @@ export class IdempotencyService {
       ttlSeconds: config.ttlSeconds ?? DEFAULT_TTL,
       namespace: config.namespace ?? 'default',
       retryFailures: config.retryFailures ?? false,
+      storeResultBody: config.storeResultBody ?? true,
     }
     this.storageMethod = config.forceStorage ?? getStorageMethod()
     logger.info(`IdempotencyService using ${this.storageMethod} storage`, {
@@ -441,7 +450,9 @@ export class IdempotencyService {
 
       await this.storeResult(
         claimResult.normalizedKey,
-        { success: true, result, status: 'completed' },
+        this.config.storeResultBody
+          ? { success: true, result, status: 'completed' }
+          : { success: true, status: 'completed' },
         claimResult.storageMethod
       )
 
@@ -510,15 +521,22 @@ export class IdempotencyService {
   }
 }
 
+/**
+ * As a webhook receiver we only need a "we saw this delivery" marker —
+ * the provider's retry just needs a 2xx, not our cached response body.
+ * TTL must exceed the longest provider retry window (Gmail / Pub-Sub: 7d).
+ */
 export const webhookIdempotency = new IdempotencyService({
   namespace: 'webhook',
   ttlSeconds: 60 * 60 * 24 * 7, // 7 days
+  storeResultBody: false,
 })
 
 export const pollingIdempotency = new IdempotencyService({
   namespace: 'polling',
   ttlSeconds: 60 * 60 * 24 * 3, // 3 days
   retryFailures: true,
+  storeResultBody: false,
 })
 
 /**