diff --git a/cron/scheduler.py b/cron/scheduler.py
index 34bf76b345..e6db77c098 100644
--- a/cron/scheduler.py
+++ b/cron/scheduler.py
@@ -219,6 +219,21 @@ def _deliver_result(job: dict, content: str, adapters=None, loop=None) -> Option
     chat_id = target["chat_id"]
     thread_id = target.get("thread_id")
 
+    # Diagnostic: log thread_id for topic-aware delivery debugging
+    origin = job.get("origin") or {}
+    origin_thread = origin.get("thread_id")
+    if origin_thread and not thread_id:
+        logger.warning(
+            "Job '%s': origin has thread_id=%s but delivery target lost it "
+            "(deliver=%s, target=%s)",
+            job["id"], origin_thread, job.get("deliver", "local"), target,
+        )
+    elif thread_id:
+        logger.debug(
+            "Job '%s': delivering to %s:%s thread_id=%s",
+            job["id"], platform_name, chat_id, thread_id,
+        )
+
     from tools.send_message_tool import _send_to_platform
     from gateway.config import load_gateway_config, Platform
 
diff --git a/tools/cronjob_tools.py b/tools/cronjob_tools.py
index 80c88e3534..d5c81ad7a8 100644
--- a/tools/cronjob_tools.py
+++ b/tools/cronjob_tools.py
@@ -6,12 +6,15 @@ Compatibility wrappers remain for direct Python callers and legacy tests.
 """
 
 import json
+import logging
 import os
 import re
 import sys
 from pathlib import Path
 from typing import Any, Dict, List, Optional
 
+logger = logging.getLogger(__name__)
+
 # Import from cron module (will be available when properly installed)
 sys.path.insert(0, str(Path(__file__).parent.parent))
 
@@ -68,11 +71,17 @@ def _origin_from_env() -> Optional[Dict[str, str]]:
     origin_platform = get_session_env("HERMES_SESSION_PLATFORM")
     origin_chat_id = get_session_env("HERMES_SESSION_CHAT_ID")
     if origin_platform and origin_chat_id:
+        thread_id = get_session_env("HERMES_SESSION_THREAD_ID") or None
+        if thread_id:
+            logger.debug(
+                "Cron origin captured thread_id=%s for %s:%s",
+                thread_id, origin_platform, origin_chat_id,
+            )
         return {
             "platform": origin_platform,
             "chat_id": origin_chat_id,
             "chat_name": get_session_env("HERMES_SESSION_CHAT_NAME") or None,
-            "thread_id": get_session_env("HERMES_SESSION_THREAD_ID") or None,
+            "thread_id": thread_id,
         }
     return None
 
@@ -456,7 +465,7 @@ Important safety rule: cron-run sessions should not recursively schedule more cr
             },
             "deliver": {
                 "type": "string",
-                "description": "Delivery target: origin, local, telegram, discord, slack, whatsapp, signal, weixin, matrix, mattermost, homeassistant, dingtalk, feishu, wecom, wecom_callback, email, sms, bluebubbles, or platform:chat_id or platform:chat_id:thread_id for Telegram topics. Examples: 'origin', 'local', 'telegram', 'telegram:-1001234567890:17585', 'discord:#engineering'"
+                "description": "Omit this parameter to auto-deliver back to the current chat and topic (recommended). Auto-detection preserves thread/topic context. Only set explicitly when the user asks to deliver somewhere OTHER than the current conversation. Values: 'origin' (same as omitting), 'local' (no delivery, save only), or platform:chat_id:thread_id for a specific destination. Examples: 'telegram:-1001234567890:17585', 'discord:#engineering'. WARNING: 'platform:chat_id' without :thread_id loses topic targeting."
             },
             "skills": {
                 "type": "array",