fix(weixin): keep multi-line messages in single bubble by default (#7903)

The Weixin adapter was splitting responses at every top-level newline,
causing notification spam (up to 70 API calls for a single long markdown
response). This salvages the best aspects of six contributor PRs:

Compact mode (new default):
- Messages under the 4000-char limit stay as a single bubble even with
  multiple lines, paragraphs, and code blocks
- Only oversized messages get split at logical markdown boundaries
- Inter-chunk delay (0.3s) between chunks prevents WeChat rate-limit drops

Legacy mode (opt-in):
- Set split_multiline_messages: true in platforms.weixin.extra config
- Or set WEIXIN_SPLIT_MULTILINE_MESSAGES=true env var
- Restores the old per-line splitting behavior

Salvaged from PRs #7797 (guantoubaozi), #7792 (luoxiao6645),
#7838 (qyx596), #7825 (weedge), #7784 (sherunlock03), #7773 (JnyRoad).
Core fix unanimous across all six; config toggle from #7838; inter-chunk
delay from #7825.

gateway/config.py

@@ -1017,6 +1017,9 @@ def _apply_env_overrides(config: GatewayConfig) -> None:
         weixin_group_allowed_users = os.getenv("WEIXIN_GROUP_ALLOWED_USERS", "").strip()
         if weixin_group_allowed_users:
             extra["group_allow_from"] = weixin_group_allowed_users
+        weixin_split_multiline = os.getenv("WEIXIN_SPLIT_MULTILINE_MESSAGES", "").strip()
+        if weixin_split_multiline:
+            extra["split_multiline_messages"] = weixin_split_multiline
         weixin_home = os.getenv("WEIXIN_HOME_CHANNEL", "").strip()
         if weixin_home:
             config.platforms[Platform.WEIXIN].home_channel = HomeChannel(

gateway/platforms/weixin.py

@@ -755,23 +755,58 @@ def _pack_markdown_blocks_for_weixin(content: str, max_length: int) -> List[str]
     return packed
 
 
-def _split_text_for_weixin_delivery(content: str, max_length: int) -> List[str]:
+def _split_text_for_weixin_delivery(
+    content: str, max_length: int, split_per_line: bool = False,
+) -> List[str]:
     """Split content into sequential Weixin messages.
 
-    Prefer one message per top-level line/markdown unit when the author used
-    explicit line breaks. Oversized units fall back to block-aware packing so
-    long code fences still split safely.
-    """
-    if len(content) <= max_length and "\n" not in content:
-        return [content]
+    *compact* (default): Keep everything in a single message whenever it fits
+    within the platform limit, even when the author used explicit line breaks.
+    Only fall back to block-aware packing when the payload exceeds
+    ``max_length``.
 
-    chunks: List[str] = []
-    for unit in _split_delivery_units_for_weixin(content):
-        if len(unit) <= max_length:
-            chunks.append(unit)
-            continue
-        chunks.extend(_pack_markdown_blocks_for_weixin(unit, max_length))
-    return chunks or [content]
+    *per_line* (``split_per_line=True``): Legacy behavior — top-level line
+    breaks become separate chat messages; oversized units still use
+    block-aware packing.
+
+    The active mode is controlled via ``config.yaml`` ->
+    ``platforms.weixin.extra.split_multiline_messages`` (``true`` / ``false``)
+    or the env var ``WEIXIN_SPLIT_MULTILINE_MESSAGES``.
+    """
+    if split_per_line:
+        # Legacy: one message per top-level delivery unit.
+        if len(content) <= max_length and "\n" not in content:
+            return [content]
+        chunks: List[str] = []
+        for unit in _split_delivery_units_for_weixin(content):
+            if len(unit) <= max_length:
+                chunks.append(unit)
+                continue
+            chunks.extend(_pack_markdown_blocks_for_weixin(unit, max_length))
+        return chunks or [content]
+
+    # Compact (default): single message when under the limit.
+    if len(content) <= max_length:
+        return [content]
+    return _pack_markdown_blocks_for_weixin(content, max_length) or [content]
+
+
+def _coerce_bool(value: Any, default: bool = True) -> bool:
+    """Coerce a config value to bool, tolerating strings like ``"true"``."""
+    if value is None:
+        return default
+    if isinstance(value, bool):
+        return value
+    if isinstance(value, (int, float)):
+        return bool(value)
+    text = str(value).strip().lower()
+    if not text:
+        return default
+    if text in {"1", "true", "yes", "on"}:
+        return True
+    if text in {"0", "false", "no", "off"}:
+        return False
+    return default
 
 
 def _extract_text(item_list: List[Dict[str, Any]]) -> str:
@@ -991,6 +1026,11 @@ class WeixinAdapter(BasePlatformAdapter):
             group_allow_from = os.getenv("WEIXIN_GROUP_ALLOWED_USERS", "")
         self._allow_from = self._coerce_list(allow_from)
         self._group_allow_from = self._coerce_list(group_allow_from)
+        self._split_multiline_messages = _coerce_bool(
+            extra.get("split_multiline_messages")
+            or os.getenv("WEIXIN_SPLIT_MULTILINE_MESSAGES"),
+            default=False,
+        )
 
         if self._account_id and not self._token:
             persisted = load_weixin_account(hermes_home, self._account_id)
@@ -1330,7 +1370,9 @@ class WeixinAdapter(BasePlatformAdapter):
             logger.debug("[%s] getConfig failed for %s: %s", self.name, _safe_id(user_id), exc)
 
     def _split_text(self, content: str) -> List[str]:
-        return _split_text_for_weixin_delivery(content, self.MAX_MESSAGE_LENGTH)
+        return _split_text_for_weixin_delivery(
+            content, self.MAX_MESSAGE_LENGTH, self._split_multiline_messages,
+        )
 
     async def send(
         self,
@@ -1344,7 +1386,10 @@ class WeixinAdapter(BasePlatformAdapter):
         context_token = self._token_store.get(self._account_id, chat_id)
         last_message_id: Optional[str] = None
         try:
-            for chunk in self._split_text(self.format_message(content)):
+            chunks = self._split_text(self.format_message(content))
+            for idx, chunk in enumerate(chunks):
+                if idx > 0:
+                    await asyncio.sleep(0.3)
                 client_id = f"hermes-weixin-{uuid.uuid4().hex}"
                 await _send_message(
                     self._session,

tests/gateway/test_weixin.py

@@ -62,15 +62,15 @@ class TestWeixinFormatting:
 
 
 class TestWeixinChunking:
-    def test_split_text_sends_top_level_newlines_as_separate_messages(self):
+    def test_split_text_keeps_short_multiline_message_in_single_chunk(self):
         adapter = _make_adapter()
 
         content = adapter.format_message("第一行\n第二行\n第三行")
         chunks = adapter._split_text(content)
 
-        assert chunks == ["第一行", "第二行", "第三行"]
+        assert chunks == ["第一行\n第二行\n第三行"]
 
-    def test_split_text_keeps_indented_followup_with_previous_line(self):
+    def test_split_text_keeps_short_reformatted_table_in_single_chunk(self):
         adapter = _make_adapter()
 
         content = adapter.format_message(
@@ -81,10 +81,7 @@ class TestWeixinChunking:
         )
         chunks = adapter._split_text(content)
 
-        assert chunks == [
-            "- Setting: Timeout\n  Value: 30s",
-            "- Setting: Retries\n  Value: 3",
-        ]
+        assert chunks == [content]
 
     def test_split_text_keeps_complete_code_block_together_when_possible(self):
         adapter = _make_adapter()
@@ -114,6 +111,23 @@ class TestWeixinChunking:
         assert all(len(chunk) <= adapter.MAX_MESSAGE_LENGTH for chunk in chunks)
         assert all(chunk.count("```") >= 2 for chunk in chunks)
 
+    def test_split_text_can_restore_legacy_multiline_splitting_via_config(self):
+        adapter = WeixinAdapter(
+            PlatformConfig(
+                enabled=True,
+                extra={
+                    "account_id": "acct",
+                    "token": "***",
+                    "split_multiline_messages": True,
+                },
+            )
+        )
+
+        content = adapter.format_message("第一行\n第二行\n第三行")
+        chunks = adapter._split_text(content)
+
+        assert chunks == ["第一行", "第二行", "第三行"]
+
 
 class TestWeixinConfig:
     def test_apply_env_overrides_configures_weixin(self):
@@ -127,6 +141,7 @@ class TestWeixinConfig:
                 "WEIXIN_BASE_URL": "https://ilink.example.com/",
                 "WEIXIN_CDN_BASE_URL": "https://cdn.example.com/c2c/",
                 "WEIXIN_DM_POLICY": "allowlist",
+                "WEIXIN_SPLIT_MULTILINE_MESSAGES": "true",
                 "WEIXIN_ALLOWED_USERS": "wxid_1,wxid_2",
                 "WEIXIN_HOME_CHANNEL": "wxid_1",
                 "WEIXIN_HOME_CHANNEL_NAME": "Primary DM",
@@ -142,6 +157,7 @@ class TestWeixinConfig:
         assert platform_config.extra["base_url"] == "https://ilink.example.com"
         assert platform_config.extra["cdn_base_url"] == "https://cdn.example.com/c2c"
         assert platform_config.extra["dm_policy"] == "allowlist"
+        assert platform_config.extra["split_multiline_messages"] == "true"
         assert platform_config.extra["allow_from"] == "wxid_1,wxid_2"
         assert platform_config.home_channel == HomeChannel(Platform.WEIXIN, "wxid_1", "Primary DM")
 

website/docs/user-guide/messaging/weixin.md

@@ -66,6 +66,9 @@ WEIXIN_ACCOUNT_ID=your-account-id
 WEIXIN_DM_POLICY=open
 WEIXIN_ALLOWED_USERS=user_id_1,user_id_2
 
+# Optional: restore legacy multiline splitting behavior
+# WEIXIN_SPLIT_MULTILINE_MESSAGES=true
+
 # Optional: home channel for cron/notifications
 WEIXIN_HOME_CHANNEL=chat_id
 WEIXIN_HOME_CHANNEL_NAME=Home
@@ -88,7 +91,7 @@ The adapter will restore saved credentials, connect to the iLink API, and begin
 - **AES-128-ECB encrypted CDN** — automatic encryption/decryption for all media transfers
 - **Context token persistence** — disk-backed reply continuity across restarts
 - **Markdown formatting** — headers, tables, and code blocks are reformatted for WeChat readability
-- **Smart message chunking** — long messages are split at logical boundaries (paragraphs, code fences)
+- **Smart message chunking** — messages stay as a single bubble when under the limit; only oversized payloads split at logical boundaries
 - **Typing indicators** — shows "typing…" status in the WeChat client while the agent processes
 - **SSRF protection** — outbound media URLs are validated before download
 - **Message deduplication** — 5-minute sliding window prevents double-processing
@@ -108,6 +111,7 @@ Set these in `config.yaml` under `platforms.weixin.extra`:
 | `group_policy` | `disabled` | Group access: `open`, `allowlist`, `disabled` |
 | `allow_from` | `[]` | User IDs allowed for DMs (when dm_policy=allowlist) |
 | `group_allow_from` | `[]` | Group IDs allowed (when group_policy=allowlist) |
+| `split_multiline_messages` | `false` | When `true`, split multi-line replies into multiple chat messages (legacy behavior). When `false`, keep multi-line replies as one message unless they exceed the length limit. |
 
 ## Access Policies
 
@@ -211,13 +215,14 @@ WeChat's personal chat does not natively render full Markdown. The adapter refor
 
 ## Message Chunking
 
-Long messages are split intelligently for chat delivery:
+Messages are delivered as a single chat message whenever they fit within the platform limit. Only oversized payloads are split for delivery:
 
 - Maximum message length: **4000 characters**
-- Split points prefer paragraph boundaries and blank lines
-- Code fences are kept intact (never split mid-block)
-- Indented continuation lines (sub-items in reformatted tables/lists) stay with their parent
+- Messages under the limit stay intact even when they contain multiple paragraphs or line breaks
+- Oversized messages split at logical boundaries (paragraphs, blank lines, code fences)
+- Code fences are kept intact whenever possible (never split mid-block unless the fence itself exceeds the limit)
 - Oversized individual blocks fall back to the base adapter's truncation logic
+- A 0.3 s inter-chunk delay prevents WeChat rate-limit drops when multiple chunks are sent
 
 ## Typing Indicators