diff --git a/src/untether/telegram/commands/media.py b/src/untether/telegram/commands/media.py
index a3e28879..b22547a6 100644
--- a/src/untether/telegram/commands/media.py
+++ b/src/untether/telegram/commands/media.py
@@ -22,6 +22,7 @@
 
 if TYPE_CHECKING:
     from ..bridge import TelegramBridgeConfig
+    from ..chat_prefs import ChatPrefsStore
 
 
 async def _handle_media_group(
@@ -37,6 +38,7 @@ async def _handle_media_group(
         Awaitable[ResolvedMessage | None],
     ]
     | None = None,
+    chat_prefs: ChatPrefsStore | None = None,
 ) -> None:
     if not messages:
         return
@@ -47,15 +49,25 @@ async def _handle_media_group(
     )
     reply = make_reply(cfg, command_msg)
     topic_key = _topic_key(command_msg, cfg) if topic_store is not None else None
+    # keep in sync with loop.py:build_message_context — same ambient-context
+    # fallback ladder: topic-bound → chat_prefs chat-bound → topic-merged default.
     chat_project = _topics_chat_project(cfg, command_msg.chat_id)
     bound_context = (
         await topic_store.get_context(*topic_key)
         if topic_store is not None and topic_key is not None
         else None
     )
-    ambient_context = _merge_topic_context(
-        chat_project=chat_project, bound=bound_context
-    )
+    chat_bound_context = None
+    if chat_prefs is not None:
+        chat_bound_context = await chat_prefs.get_context(command_msg.chat_id)
+    if bound_context is not None:
+        ambient_context = _merge_topic_context(
+            chat_project=chat_project, bound=bound_context
+        )
+    elif chat_bound_context is not None:
+        ambient_context = chat_bound_context
+    else:
+        ambient_context = _merge_topic_context(chat_project=chat_project, bound=None)
     command_id, args_text = _parse_slash_command(command_msg.text)
     if command_id == "file":
         command, rest, error = parse_file_command(args_text)
diff --git a/src/untether/telegram/loop.py b/src/untether/telegram/loop.py
index a19130b9..85aaa64c 100644
--- a/src/untether/telegram/loop.py
+++ b/src/untether/telegram/loop.py
@@ -1102,6 +1102,7 @@ async def _flush_media_group(self, key: tuple[int, str]) -> None:
                     self._topic_store,
                     self._run_prompt_from_upload,
                     self._resolve_prompt_message,
+                    chat_prefs=self._chat_prefs,
                 )
                 logger.debug(
                     "media_group.flush.ok",
diff --git a/tests/test_telegram_media_command.py b/tests/test_telegram_media_command.py
index 8a6bed97..cf6a0e4e 100644
--- a/tests/test_telegram_media_command.py
+++ b/tests/test_telegram_media_command.py
@@ -89,6 +89,49 @@ async def _fake_handle(*_args, **_kwargs) -> None:
     assert calls["count"] == 1
 
 
+class _FakeChatPrefs:
+    """Minimal ChatPrefsStore stub — only ``get_context`` is exercised."""
+
+    def __init__(self, context: RunContext | None) -> None:
+        self._context = context
+
+    async def get_context(self, _chat_id: int) -> RunContext | None:
+        return self._context
+
+
+@pytest.mark.anyio
+async def test_media_group_uses_chat_prefs_bound_context(monkeypatch) -> None:
+    """Media-group uploads must fall back to chat_prefs-bound context.
+
+    Regression for the channelo bug: with no topic binding, no default_project
+    and no chat_map entry, a media group resolved ambient_context=None and
+    failed with "no project context available". The single-file path already
+    consulted chat_prefs; the media-group path did not.
+    """
+    transport = FakeTransport()
+    cfg = replace(make_cfg(transport), files=TelegramFilesSettings(enabled=True))
+    msg = _msg("")
+    captured: dict[str, RunContext | None] = {}
+
+    async def _fake_handle(
+        _cfg, _msg, _rest, _ordered, ambient_context, _topic_store
+    ) -> None:
+        captured["ambient_context"] = ambient_context
+
+    monkeypatch.setattr(media_commands, "_handle_file_put_group", _fake_handle)
+
+    await media_commands._handle_media_group(
+        cfg,
+        [msg],
+        topic_store=None,
+        chat_prefs=_FakeChatPrefs(RunContext(project="auditor-toolkit")),
+    )
+
+    ambient = captured["ambient_context"]
+    assert ambient is not None
+    assert ambient.project == "auditor-toolkit"
+
+
 @pytest.mark.anyio
 async def test_media_group_auto_put_prompt_resolve_none(monkeypatch) -> None:
     transport = FakeTransport()