fix(wechat): rotate polluted image sessions before follow-up turns

After a successful image report flow, Goose may keep image_url parts that
DeepSeek rejects on later turns while PUT scrub returns 405. Detect polluted
sessions up front, rotate to a fresh agent route with carried assistant
context, and recover image URLs from recent media on historical retries.

Co-authored-by: Cursor <cursoragent@cursor.com>

wechat-mp.mjs

@@ -85,6 +85,7 @@ import { resolveMindSpaceUserPublishDir } from './mindspace-runtime-config.mjs';
 import {
   buildPageDataCollectFailureText,
 } from './mindspace-page-data-finish-guard.mjs';
+import { conversationHasImageUrlContent } from './chat-image-turn-scope.mjs';
 
 export { buildWechatAgentPrompt };
 
@@ -1097,9 +1098,14 @@ export function isWechatHistoricalImageSessionError(message) {
 export const WECHAT_IMAGE_STORED_ACK_TEXT =
   '已收到图片。请直接告诉我接下来要做什么，例如：解读报告并生成页面。';
 
-export function prepareWechatIntentForHistoricalImageRetry(intent) {
+export function resolveWechatRecentMediaPublicUrl(recentMediaEntry) {
+  if (!recentMediaEntry?.items?.length) return '';
+  return String(recentMediaEntry.items.at(-1)?.media?.publicUrl ?? '').trim();
+}
+
+export function prepareWechatIntentForHistoricalImageRetry(intent, { fallbackImageUrl = '' } = {}) {
   if (!intent || typeof intent !== 'object') return intent;
-  const imageUrl = String(intent.media?.publicUrl ?? '').trim();
+  const imageUrl = String(intent.media?.publicUrl ?? fallbackImageUrl ?? '').trim();
   const agentText = String(intent.agentText ?? '').trim();
   if (imageUrl && !agentText.includes(imageUrl)) {
     intent.agentText = agentText
@@ -2185,15 +2191,23 @@ export function createWechatMpService({
     retainUnlinkedRoute = false,
     userContext = null,
   }) => {
-    if (forceNew) {
-      await userAuth.clearWechatAgentRoute(config.appId, openid);
-    }
     const workingDir = await userAuth.resolveWorkingDir(userId);
     let sessionPolicy =
       await userAuth.getAgentSessionPolicy(userId);
     const publishLayout = await userAuth.getUserPublishLayout(userId);
     const addressName = resolveWechatAddressName(userContext);
     let carriedSessionContentForNewSession = '';
+    if (forceNew) {
+      const routeBeforeForceNew = await userAuth.getWechatAgentRoute(config.appId, openid);
+      if (routeBeforeForceNew?.agentSessionId) {
+        carriedSessionContentForNewSession = await fetchLastSubstantiveAssistantFromSession(
+          fetchForSession,
+          routeBeforeForceNew.agentSessionId,
+        );
+        rememberedWechatContexts.delete(routeBeforeForceNew.agentSessionId);
+      }
+      await userAuth.clearWechatAgentRoute(config.appId, openid);
+    }
     const existingRoute = await userAuth.getWechatAgentRoute(config.appId, openid);
     if (existingRoute?.agentSessionId) {
       const now = Date.now();
@@ -2405,6 +2419,53 @@ export function createWechatMpService({
     };
   };
 
+  const rotateWechatSessionIfImagePolluted = async ({
+    userId,
+    openid,
+    sessionId,
+    user,
+    carriedSessionContent = '',
+  }) => {
+    if (!sessionId) {
+      return { sessionId, carriedSessionContent, rotated: false };
+    }
+    try {
+      const response = await fetchForSession(
+        sessionId,
+        `/sessions/${encodeURIComponent(sessionId)}`,
+      );
+      if (!response.ok) {
+        return { sessionId, carriedSessionContent, rotated: false };
+      }
+      const payload = await readJsonResponse(response);
+      const conversation = Array.isArray(payload?.conversation) ? payload.conversation : [];
+      if (!conversationHasImageUrlContent(conversation)) {
+        return { sessionId, carriedSessionContent, rotated: false };
+      }
+      logger.warn?.('WeChat MP rotating image-polluted agent session before reply:', {
+        agentSessionId: sessionId,
+        conversationLength: conversation.length,
+      });
+      const nextRoute = await ensureWechatAgentSession({
+        userId,
+        openid,
+        forceNew: true,
+        userContext: user,
+      });
+      const nextCarried = String(carriedSessionContent ?? '').trim()
+        || String(nextRoute.carriedSessionContent ?? '').trim();
+      return {
+        sessionId: nextRoute.sessionId,
+        carriedSessionContent: nextCarried,
+        rotated: true,
+        isNewSession: nextRoute.isNewSession,
+      };
+    } catch (err) {
+      logger.warn?.('WeChat MP image-polluted session rotate skipped:', err);
+      return { sessionId, carriedSessionContent, rotated: false };
+    }
+  };
+
   const refreshWechatSessionSnapshot = async (sessionId, userId) => {
     if (!sessionId || !userId || typeof refreshSessionSnapshot !== 'function') return;
     try {
@@ -2712,6 +2773,26 @@ export function createWechatMpService({
       return { sessionId };
     }
     await rememberWechatUserContext(sessionId, user, { forceBootstrap: route.isNewSession });
+    const pollutionRotation = await rotateWechatSessionIfImagePolluted({
+      userId: user.userId,
+      openid: inbound.fromUserName,
+      sessionId,
+      user,
+      carriedSessionContent,
+    });
+    if (pollutionRotation.rotated) {
+      sessionId = pollutionRotation.sessionId;
+      route = {
+        ...route,
+        sessionId,
+        isNewSession: pollutionRotation.isNewSession ?? true,
+      };
+      if (pollutionRotation.carriedSessionContent) {
+        carriedSessionContent = pollutionRotation.carriedSessionContent;
+      }
+      await ensureSessionProvider(sessionId);
+      await rememberWechatUserContext(sessionId, user, { forceBootstrap: true });
+    }
     if (
       wechatIntent.kind === 'page.generate'
       && sessionPageContinuation
@@ -3177,7 +3258,11 @@ export function createWechatMpService({
         await ensureSessionProvider(sessionId);
         await rememberWechatUserContext(sessionId, user, { forceBootstrap: route.isNewSession });
         if (historicalImageError) {
-          prepareWechatIntentForHistoricalImageRetry(intent);
+          prepareWechatIntentForHistoricalImageRetry(intent, {
+            fallbackImageUrl: resolveWechatRecentMediaPublicUrl(
+              recentMediaByOpenid.get(String(inbound.fromUserName ?? '').trim()),
+            ),
+          });
         }
         const retryId = crypto.randomUUID();
         const retryStartedAt = Date.now();