fix: suppress duplicate cron sends to auto-delivery targets

Allow cron runs to keep using send_message for additional destinations, but
skip same-target sends when the scheduler will already auto-deliver the final
response there. Add prompt/tool guidance, docs, and regression coverage for
origin/home-channel resolution and thread-aware comparisons.

tests/tools/test_send_message_tool.py

@@ -2,6 +2,7 @@
 
 import asyncio
 import json
+import os
 import sys
 from pathlib import Path
 from types import SimpleNamespace
@@ -29,6 +30,118 @@ def _install_telegram_mock(monkeypatch, bot):
 
 
 class TestSendMessageTool:
+    def test_cron_duplicate_target_is_skipped_and_explained(self):
+        home = SimpleNamespace(chat_id="-1001")
+        config, _telegram_cfg = _make_config()
+        config.get_home_channel = lambda _platform: home
+
+        with patch.dict(
+            os.environ,
+            {
+                "HERMES_CRON_AUTO_DELIVER_PLATFORM": "telegram",
+                "HERMES_CRON_AUTO_DELIVER_CHAT_ID": "-1001",
+            },
+            clear=False,
+        ), \
+             patch("gateway.config.load_gateway_config", return_value=config), \
+             patch("tools.interrupt.is_interrupted", return_value=False), \
+             patch("model_tools._run_async", side_effect=_run_async_immediately), \
+             patch("tools.send_message_tool._send_to_platform", new=AsyncMock(return_value={"success": True})) as send_mock, \
+             patch("gateway.mirror.mirror_to_session", return_value=True) as mirror_mock:
+            result = json.loads(
+                send_message_tool(
+                    {
+                        "action": "send",
+                        "target": "telegram",
+                        "message": "hello",
+                    }
+                )
+            )
+
+        assert result["success"] is True
+        assert result["skipped"] is True
+        assert result["reason"] == "cron_auto_delivery_duplicate_target"
+        assert "final response" in result["note"]
+        send_mock.assert_not_awaited()
+        mirror_mock.assert_not_called()
+
+    def test_cron_different_target_still_sends(self):
+        config, telegram_cfg = _make_config()
+
+        with patch.dict(
+            os.environ,
+            {
+                "HERMES_CRON_AUTO_DELIVER_PLATFORM": "telegram",
+                "HERMES_CRON_AUTO_DELIVER_CHAT_ID": "-1001",
+            },
+            clear=False,
+        ), \
+             patch("gateway.config.load_gateway_config", return_value=config), \
+             patch("tools.interrupt.is_interrupted", return_value=False), \
+             patch("model_tools._run_async", side_effect=_run_async_immediately), \
+             patch("tools.send_message_tool._send_to_platform", new=AsyncMock(return_value={"success": True})) as send_mock, \
+             patch("gateway.mirror.mirror_to_session", return_value=True) as mirror_mock:
+            result = json.loads(
+                send_message_tool(
+                    {
+                        "action": "send",
+                        "target": "telegram:-1002",
+                        "message": "hello",
+                    }
+                )
+            )
+
+        assert result["success"] is True
+        assert result.get("skipped") is not True
+        send_mock.assert_awaited_once_with(
+            Platform.TELEGRAM,
+            telegram_cfg,
+            "-1002",
+            "hello",
+            thread_id=None,
+            media_files=[],
+        )
+        mirror_mock.assert_called_once_with("telegram", "-1002", "hello", source_label="cli", thread_id=None)
+
+    def test_cron_same_chat_different_thread_still_sends(self):
+        config, telegram_cfg = _make_config()
+
+        with patch.dict(
+            os.environ,
+            {
+                "HERMES_CRON_AUTO_DELIVER_PLATFORM": "telegram",
+                "HERMES_CRON_AUTO_DELIVER_CHAT_ID": "-1001",
+                "HERMES_CRON_AUTO_DELIVER_THREAD_ID": "17585",
+            },
+            clear=False,
+        ), \
+             patch("gateway.config.load_gateway_config", return_value=config), \
+             patch("tools.interrupt.is_interrupted", return_value=False), \
+             patch("model_tools._run_async", side_effect=_run_async_immediately), \
+             patch("tools.send_message_tool._send_to_platform", new=AsyncMock(return_value={"success": True})) as send_mock, \
+             patch("gateway.mirror.mirror_to_session", return_value=True) as mirror_mock:
+            result = json.loads(
+                send_message_tool(
+                    {
+                        "action": "send",
+                        "target": "telegram:-1001:99999",
+                        "message": "hello",
+                    }
+                )
+            )
+
+        assert result["success"] is True
+        assert result.get("skipped") is not True
+        send_mock.assert_awaited_once_with(
+            Platform.TELEGRAM,
+            telegram_cfg,
+            "-1001",
+            "hello",
+            thread_id="99999",
+            media_files=[],
+        )
+        mirror_mock.assert_called_once_with("telegram", "-1001", "hello", source_label="cli", thread_id="99999")
+
     def test_sends_to_explicit_telegram_topic_target(self):
         config, telegram_cfg = _make_config()