fix(weixin): retry send without expired context_token on ret=-2

When the iLink API returns ret=-2 (parameter error), it is often caused
by an expired context_token rather than a malformed payload. After a
gateway restart, the cached token can become stale within ~90 seconds if
no new inbound message refreshes it, causing all outbound replies to fail
silently.

Changes:
- _send_text: retry once without context_token when ret=-2 and a token
  was present; if the retry succeeds, clear the expired token from cache.
- Remove leftover @staticmethod on _check_response_error so self.logger
  and the body parameter work correctly.
- Bump WEIXIN_CHANNEL_VERSION from 2.1.1 -> 2.1.7 to match the reference
  openclaw-weixin plugin.
- Add tests covering the ret=-2 retry path, failure path, and no-token
  path.

References:
- openclaw/openclaw#61174 (context_token expiry after long agent turns)
- hermes-agent#21011 (ret=-2 rate limiting / parameter error)

nanobot/channels/weixin.py

@@ -11,6 +11,7 @@ from __future__ import annotations
 
 import asyncio
 import base64
+import copy
 import hashlib
 import json
 import os
@@ -54,7 +55,7 @@ MESSAGE_TYPE_BOT = 2
 MESSAGE_STATE_FINISH = 2
 
 WEIXIN_MAX_MESSAGE_LEN = 4000
-WEIXIN_CHANNEL_VERSION = "2.1.1"
+WEIXIN_CHANNEL_VERSION = "2.1.7"
 ILINK_APP_ID = "bot"
 
 
@@ -526,8 +527,7 @@ class WeixinChannel(BaseChannel):
                 f"WeChat session paused, {remaining_min} min remaining (errcode {ERRCODE_SESSION_EXPIRED})"
             )
 
-    @staticmethod
-    def _check_response_error(data: dict, operation: str) -> None:
+    def _check_response_error(self, data: dict, operation: str, *, body: dict | None = None) -> None:
         """Check both ``ret`` and ``errcode`` like the reference TS code.
 
         The iLink API may signal failure through either field (or both).
@@ -537,10 +537,11 @@ class WeixinChannel(BaseChannel):
         ret = data.get("ret", 0)
         errcode = data.get("errcode", 0)
         is_error = (ret is not None and ret != 0) or (errcode is not None and errcode != 0)
-        if is_error:
-            raise RuntimeError(
-                f"WeChat {operation} error (ret={ret}, errcode={errcode}): {data.get('errmsg', '')}"
-            )
+        if not is_error:
+            return
+        raise RuntimeError(
+            f"WeChat {operation} error (ret={ret}, errcode={errcode}): {data.get('errmsg', '')}"
+        )
 
     async def _poll_once(self) -> None:
         remaining = self._session_pause_remaining_s()
@@ -1139,7 +1140,37 @@ class WeixinChannel(BaseChannel):
         }
 
         data = await self._api_post("ilink/bot/sendmessage", body)
-        self._check_response_error(data, "send text")
+        ret = data.get("ret", 0)
+        errcode = data.get("errcode", 0)
+
+        # If ret=-2 (parameter error / rate limit / expired token) and we sent
+        # with a context_token, retry once without it.  The openclaw reference
+        # plugin can send without a token (it just warns), and issue #61174
+        # shows that expired context_tokens are a common cause of ret=-2.
+        if ret == -2 and context_token:
+            self.logger.warning(
+                "WeChat send text returned ret=-2 for {} (client_id={}); "
+                "retrying without context_token",
+                to_user_id,
+                client_id,
+            )
+            body_no_ctx = copy.deepcopy(body)
+            body_no_ctx["msg"].pop("context_token", None)
+            data = await self._api_post("ilink/bot/sendmessage", body_no_ctx)
+            ret = data.get("ret", 0)
+            errcode = data.get("errcode", 0)
+            if ret == 0 and (errcode == 0 or errcode is None):
+                self.logger.warning(
+                    "WeChat send text succeeded WITHOUT context_token for {}; "
+                    "clearing expired token from cache",
+                    to_user_id,
+                )
+                self._context_tokens.pop(to_user_id, None)
+                self._save_state()
+                self.logger.debug("WeChat text sent to {} (client_id={})", to_user_id, client_id)
+                return
+
+        self._check_response_error(data, "send text", body=body)
         self.logger.debug("WeChat text sent to {} (client_id={})", to_user_id, client_id)
 
     async def _send_media_file(
@@ -1286,7 +1317,7 @@ class WeixinChannel(BaseChannel):
         }
 
         data = await self._api_post("ilink/bot/sendmessage", body)
-        self._check_response_error(data, "send media")
+        self._check_response_error(data, "send media", body=body)
 
 
 # ---------------------------------------------------------------------------

tests/channels/test_weixin_channel.py

@@ -48,11 +48,11 @@ def test_make_headers_includes_route_tag_when_configured() -> None:
     assert headers["Authorization"] == "Bearer token"
     assert headers["SKRouteTag"] == "123"
     assert headers["iLink-App-Id"] == "bot"
-    assert headers["iLink-App-ClientVersion"] == str((2 << 16) | (1 << 8) | 1)
+    assert headers["iLink-App-ClientVersion"] == str((2 << 16) | (1 << 8) | 7)
 
 
 def test_channel_version_matches_reference_plugin_version() -> None:
-    assert WEIXIN_CHANNEL_VERSION == "2.1.1"
+    assert WEIXIN_CHANNEL_VERSION == "2.1.7"
 
 
 def test_save_and_load_state_persists_context_tokens(tmp_path) -> None:
@@ -1362,3 +1362,71 @@ async def test_poll_loop_logs_exception_and_continues_on_poll_failure(monkeypatc
 
     assert call_count == 2
     assert any("WeChat poll loop error" in m for m in logged_messages)
+
+
+@pytest.mark.asyncio
+async def test_send_text_retries_without_context_token_on_ret_minus_two() -> None:
+    """If sendmessage returns ret=-2 with a context_token, retry without it."""
+    channel, _bus = _make_channel()
+    channel._client = object()
+    channel._token = "token"
+    channel._context_tokens["wx-user"] = "expired-token"
+
+    channel._api_post = AsyncMock(
+        side_effect=[
+            {"ret": -2},  # first attempt with token fails
+            {"ret": 0},   # retry without token succeeds
+        ]
+    )
+
+    await channel._send_text("wx-user", "hello", "expired-token")
+
+    # Should have called API twice
+    assert channel._api_post.await_count == 2
+    # First call includes context_token
+    first_body = channel._api_post.await_args_list[0].args[1]
+    assert first_body["msg"]["context_token"] == "expired-token"
+    # Second call does NOT include context_token
+    second_body = channel._api_post.await_args_list[1].args[1]
+    assert "context_token" not in second_body["msg"]
+    # Expired token should be cleared from cache
+    assert "wx-user" not in channel._context_tokens
+
+
+@pytest.mark.asyncio
+async def test_send_text_raises_when_ret_minus_two_retry_also_fails() -> None:
+    """If both attempts (with and without token) return ret=-2, raise."""
+    channel, _bus = _make_channel()
+    channel._client = object()
+    channel._token = "token"
+    channel._context_tokens["wx-user"] = "bad-token"
+
+    channel._api_post = AsyncMock(
+        side_effect=[
+            {"ret": -2},  # with token
+            {"ret": -2},  # without token
+        ]
+    )
+
+    with pytest.raises(RuntimeError, match="ret=-2"):
+        await channel._send_text("wx-user", "hello", "bad-token")
+
+    assert channel._api_post.await_count == 2
+    # Token is NOT cleared because retry also failed
+    assert channel._context_tokens.get("wx-user") == "bad-token"
+
+
+@pytest.mark.asyncio
+async def test_send_text_does_not_retry_without_token_when_no_context_token() -> None:
+    """If no context_token was provided, ret=-2 should raise immediately."""
+    channel, _bus = _make_channel()
+    channel._client = object()
+    channel._token = "token"
+
+    channel._api_post = AsyncMock(return_value={"ret": -2})
+
+    with pytest.raises(RuntimeError, match="ret=-2"):
+        await channel._send_text("wx-user", "hello", "")
+
+    # Only one API call (no retry)
+    channel._api_post.assert_awaited_once()