fix(buzz): preserve stable thread roots

plugins/platforms/buzz/adapter.py

@@ -782,7 +782,7 @@ class BuzzAdapter(BasePlatformAdapter):
         if not content:
             return SendResult(success=False, error="Empty message")
         args = ["messages", "send", "--channel", str(chat_id), "--content", "-"]
-        reply_target = reply_to or (metadata or {}).get("thread_id")
+        reply_target = (metadata or {}).get("thread_id") or reply_to
         if reply_target:
             args += ["--reply-to", str(reply_target)]
         code, out, err = await self._run_cli(args, input_text=content)
@@ -929,8 +929,9 @@ class BuzzAdapter(BasePlatformAdapter):
                 "--file", str(local),
                 "--content", "-",
             ]
-            if reply_to:
-                args += ["--reply-to", str(reply_to)]
+            reply_target = (metadata or {}).get("thread_id") or reply_to
+            if reply_target:
+                args += ["--reply-to", str(reply_target)]
             code, out, err = await self._run_cli(args, input_text=caption or "")
             if code != 0:
                 return SendResult(success=False, error=_cli_error_message(err, code), retryable=code == 2)
@@ -1310,6 +1311,23 @@ class BuzzAdapter(BasePlatformAdapter):
         # open with "@Chip" even though no mention is required there, so the
         # strip applies to both chat types.
         dispatch_text = self._strip_mention(content)
+        tags = event.get("tags")
+        thread_id = (
+            next(
+                (
+                    str(tag[1])
+                    for tag in tags
+                    if isinstance(tag, (list, tuple))
+                    and len(tag) > 3
+                    and tag[0] == "e"
+                    and tag[1]
+                    and tag[3] == "root"
+                ),
+                None,
+            )
+            if isinstance(tags, list)
+            else None
+        )
 
         await self._dispatch_message(
             text=dispatch_text,
@@ -1319,6 +1337,7 @@ class BuzzAdapter(BasePlatformAdapter):
             user_name=await self._resolve_user_name(pubkey),
             message_id=event_id,
             created_at=created_at,
+            thread_id=thread_id,
         )
 
     # ── DM classification (issue #68871) ──────────────────────────────────
@@ -1482,6 +1501,7 @@ class BuzzAdapter(BasePlatformAdapter):
         user_name: str,
         message_id: str,
         created_at: int,
+        thread_id: Optional[str] = None,
     ) -> None:
         """Build a MessageEvent and hand it to the base class handler."""
         if not self._message_handler:
@@ -1493,6 +1513,7 @@ class BuzzAdapter(BasePlatformAdapter):
             chat_type=chat_type,
             user_id=user_id,
             user_name=user_name,
+            thread_id=thread_id,
         )
 
         event = MessageEvent(

tests/gateway/test_buzz_adapter.py

@@ -828,6 +828,34 @@ class TestDmClassification:
         assert a._may_reclassify_as_dm(CHANNEL) is False
 
 
+class TestThreadRoots:
+
+    @pytest.mark.asyncio
+    async def test_inbound_root_e_tag_propagates_to_session_source(self):
+        adapter = _make_adapter()
+        adapter._channel_state[CHANNEL] = {
+            "chat_type": "group",
+            "last_ts": 0,
+            "seen": {},
+        }
+        dispatched = []
+
+        async def capture(event):
+            dispatched.append(event)
+
+        adapter._message_handler = AsyncMock()
+        adapter.handle_message = capture
+        event = _tagged_event("latest-child", CHANNEL, content="@Chip follow-up")
+        event["tags"] += [
+            ["e", "stable-root", "", "root"],
+            ["e", "latest-parent", "", "reply"],
+        ]
+
+        await adapter._handle_event(CHANNEL, adapter._channel_state[CHANNEL], event)
+
+        assert dispatched[0].source.thread_id == "stable-root"
+
+
 # ── Sending ───────────────────────────────────────────────────────────────
 
 
@@ -871,6 +899,24 @@ class TestBuzzAdapterSend:
         args, _stdin = cli.calls[0]
         assert args[args.index("--reply-to") + 1] == "buzz-event-123"
 
+    @pytest.mark.asyncio
+    async def test_send_prefers_stable_thread_root_over_latest_reply(self):
+        adapter = _make_adapter()
+        cli = _ScriptedCli()
+        cli.script("messages", "send", {"accepted": True, "event_id": "evt124"})
+        adapter._run_cli = cli
+
+        await adapter.send(
+            CHANNEL,
+            "threaded reply",
+            reply_to="latest-child",
+            metadata={"thread_id": "stable-root"},
+        )
+
+        args, _stdin = cli.calls[0]
+        assert args[args.index("--reply-to") + 1] == "stable-root"
+
+
     @pytest.mark.asyncio
     async def test_send_image_local_file_uses_file_flag(self, tmp_path):
         img = tmp_path / "shot.png"
@@ -884,6 +930,25 @@ class TestBuzzAdapterSend:
         args, _stdin = cli.calls[0]
         assert args[args.index("--file") + 1] == str(img)
 
+    @pytest.mark.asyncio
+    async def test_send_image_local_file_prefers_stable_thread_root(self, tmp_path):
+        img = tmp_path / "shot.png"
+        img.write_bytes(b"\x89PNG fake")
+        adapter = _make_adapter()
+        cli = _ScriptedCli()
+        cli.script("messages", "send", {"accepted": True, "event_id": "evt127"})
+        adapter._run_cli = cli
+
+        await adapter.send_image(
+            CHANNEL,
+            str(img),
+            reply_to="latest-child",
+            metadata={"thread_id": "stable-root"},
+        )
+
+        args, _stdin = cli.calls[0]
+        assert args[args.index("--reply-to") + 1] == "stable-root"
+
 
 # ── Lifecycle ─────────────────────────────────────────────────────────────