fix(send_message): preserve Slack and Matrix thread targets resolved from channel directory

tests/tools/test_send_message_tool.py

@@ -182,6 +182,81 @@ class TestSendMessageTool:
             force_document=False,
         )
 
+    def test_resolved_slack_thread_name_preserves_thread_id(self):
+        slack_cfg = SimpleNamespace(enabled=True, token="xoxb-test", extra={})
+        config = SimpleNamespace(
+            platforms={Platform.SLACK: slack_cfg},
+            get_home_channel=lambda _platform: None,
+        )
+
+        with patch("gateway.config.load_gateway_config", return_value=config), \
+             patch("tools.interrupt.is_interrupted", return_value=False), \
+             patch("gateway.channel_directory.resolve_channel_name", return_value="C123ABCDEF:171.000001"), \
+             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):
+            result = json.loads(
+                send_message_tool(
+                    {
+                        "action": "send",
+                        "target": "slack:ops / topic 171.000001",
+                        "message": "hello",
+                    }
+                )
+            )
+
+        assert result["success"] is True
+        send_mock.assert_awaited_once_with(
+            Platform.SLACK,
+            slack_cfg,
+            "C123ABCDEF",
+            "hello",
+            thread_id="171.000001",
+            media_files=[],
+            force_document=False,
+        )
+
+    def test_resolved_matrix_thread_name_preserves_thread_id(self):
+        matrix_cfg = SimpleNamespace(
+            enabled=True,
+            token="tok",
+            extra={"homeserver": "https://matrix.example.com"},
+        )
+        config = SimpleNamespace(
+            platforms={Platform.MATRIX: matrix_cfg},
+            get_home_channel=lambda _platform: None,
+        )
+
+        with patch("gateway.config.load_gateway_config", return_value=config), \
+             patch("tools.interrupt.is_interrupted", return_value=False), \
+             patch(
+                 "gateway.channel_directory.resolve_channel_name",
+                 return_value="!roomid:matrix.example.org:$thread123:matrix.example.org",
+             ), \
+             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):
+            result = json.loads(
+                send_message_tool(
+                    {
+                        "action": "send",
+                        "target": "matrix:Ops / topic $thread123",
+                        "message": "hello",
+                    }
+                )
+            )
+
+        assert result["success"] is True
+        send_mock.assert_awaited_once_with(
+            Platform.MATRIX,
+            matrix_cfg,
+            "!roomid:matrix.example.org",
+            "hello",
+            thread_id="$thread123:matrix.example.org",
+            media_files=[],
+            force_document=False,
+        )
+
     def test_mirror_receives_current_session_user_id(self):
         config, _telegram_cfg = _make_config()
 
@@ -503,9 +578,8 @@ class TestSendToPlatformChunking:
         assert all(call == [] for call in sent_calls[:-1])
         assert sent_calls[-1] == media
 
-    def test_matrix_media_uses_native_adapter_helper(self):
-
-        doc_path = Path("/tmp/test-send-message-matrix.pdf")
+    def test_matrix_media_uses_native_adapter_helper(self, tmp_path):
+        doc_path = tmp_path / "test-send-message-matrix.pdf"
         doc_path.write_bytes(b"%PDF-1.4 test")
 
         try:
@@ -847,6 +921,16 @@ class TestParseTargetRefDiscord:
 class TestParseTargetRefMatrix:
     """_parse_target_ref correctly handles Matrix room IDs and user MXIDs."""
 
+    def test_matrix_thread_target_is_explicit(self):
+        """Session-derived Matrix thread targets round-trip as room + event id."""
+        chat_id, thread_id, is_explicit = _parse_target_ref(
+            "matrix",
+            "!HLOQwxYGgFPMPJUSNR:matrix.org:$thread123:matrix.org",
+        )
+        assert chat_id == "!HLOQwxYGgFPMPJUSNR:matrix.org"
+        assert thread_id == "$thread123:matrix.org"
+        assert is_explicit is True
+
     def test_matrix_room_id_is_explicit(self):
         """Matrix room IDs (!) are recognized as explicit targets."""
         chat_id, thread_id, is_explicit = _parse_target_ref("matrix", "!HLOQwxYGgFPMPJUSNR:matrix.org")
@@ -919,6 +1003,12 @@ class TestParseTargetRefE164:
 class TestParseTargetRefSlack:
     """_parse_target_ref recognizes Slack channel/user IDs as explicit."""
 
+    def test_thread_target_is_explicit(self):
+        chat_id, thread_id, is_explicit = _parse_target_ref("slack", "C0B0QV5434G:171.000001")
+        assert chat_id == "C0B0QV5434G"
+        assert thread_id == "171.000001"
+        assert is_explicit is True
+
     def test_public_channel_id_is_explicit(self):
         chat_id, thread_id, is_explicit = _parse_target_ref("slack", "C0B0QV5434G")
         assert chat_id == "C0B0QV5434G"