diff --git a/src/twilio/heartbeat.ts b/src/twilio/heartbeat.ts
index 3eb096d6f..c8129834e 100644
--- a/src/twilio/heartbeat.ts
+++ b/src/twilio/heartbeat.ts
@@ -49,29 +49,33 @@ export async function runTwilioHeartbeatOnce(opts: {
         To: to,
         MessageSid: undefined,
       },
-      undefined,
+      { isHeartbeat: true },
     );
 
+    const replyPayload = Array.isArray(replyResult)
+      ? replyResult[0]
+      : replyResult;
+
     if (
-      !replyResult ||
-      (!replyResult.text &&
-        !replyResult.mediaUrl &&
-        !replyResult.mediaUrls?.length)
+      !replyPayload ||
+      (!replyPayload.text &&
+        !replyPayload.mediaUrl &&
+        !replyPayload.mediaUrls?.length)
     ) {
       logInfo("heartbeat skipped: empty reply", runtime);
       return;
     }
 
     const hasMedia = Boolean(
-      replyResult.mediaUrl || (replyResult.mediaUrls?.length ?? 0) > 0,
+      replyPayload.mediaUrl || (replyPayload.mediaUrls?.length ?? 0) > 0,
     );
-    const stripped = stripHeartbeatToken(replyResult.text);
+    const stripped = stripHeartbeatToken(replyPayload.text);
     if (stripped.shouldSkip && !hasMedia) {
       logInfo(success("heartbeat: ok (HEARTBEAT_OK)"), runtime);
       return;
     }
 
-    const finalText = stripped.text || replyResult.text || "";
+    const finalText = stripped.text || replyPayload.text || "";
     if (dryRun) {
       logInfo(
         `[dry-run] heartbeat -> ${to}: ${finalText.slice(0, 200)}`,
diff --git a/src/twilio/webhook.ts b/src/twilio/webhook.ts
index 51a1b90f4..e82970d10 100644
--- a/src/twilio/webhook.ts
+++ b/src/twilio/webhook.ts
@@ -69,7 +69,7 @@ export async function startWebhook(
     }
 
     const client = createClient(env);
-    let replyResult: ReplyPayload | undefined =
+    let replyResult: ReplyPayload | ReplyPayload[] | undefined =
       autoReply !== undefined ? { text: autoReply } : undefined;
     if (!replyResult) {
       replyResult = await getReplyFromConfig(
@@ -88,9 +88,13 @@ export async function startWebhook(
       );
     }
 
-    if (replyResult && (replyResult.text || replyResult.mediaUrl)) {
+    const replyPayload = Array.isArray(replyResult)
+      ? replyResult[0]
+      : replyResult;
+
+    if (replyPayload && (replyPayload.text || replyPayload.mediaUrl)) {
       try {
-        let mediaUrl = replyResult.mediaUrl;
+        let mediaUrl = replyPayload.mediaUrl;
         if (mediaUrl && !/^https?:\/\//i.test(mediaUrl)) {
           const hosted = await mediaHost.ensureMediaHosted(mediaUrl);
           mediaUrl = hosted.url;
@@ -98,7 +102,7 @@ export async function startWebhook(
         await client.messages.create({
           from: To,
           to: From,
-          body: replyResult.text ?? "",
+          body: replyPayload.text ?? "",
           ...(mediaUrl ? { mediaUrl: [mediaUrl] } : {}),
         });
         if (verbose)
diff --git a/src/web/auto-reply.ts b/src/web/auto-reply.ts
index bf240853e..24de637b4 100644
--- a/src/web/auto-reply.ts
+++ b/src/web/auto-reply.ts
@@ -72,7 +72,7 @@ const formatDuration = (ms: number) =>
 
 const DEFAULT_REPLY_HEARTBEAT_MINUTES = 30;
 export const HEARTBEAT_TOKEN = "HEARTBEAT_OK";
-export const HEARTBEAT_PROMPT = "HEARTBEAT ultrathink";
+export const HEARTBEAT_PROMPT = "HEARTBEAT /think:high";
 
 export function resolveReplyHeartbeatMinutes(
   cfg: ReturnType<typeof loadConfig>,