diff --git a/src/media/media-download.ts b/src/media/media-download.ts
index 0ad7b19..21be066 100644
--- a/src/media/media-download.ts
+++ b/src/media/media-download.ts
@@ -29,12 +29,15 @@ export async function downloadMediaFromItem(
   deps: {
     cdnBaseUrl: string;
     saveMedia: SaveMediaFn;
+    /** Subdirectory under the media store (e.g. "wecom/<agentId>/inbound"). Defaults to "inbound". */
+    subdir?: string;
     log: (msg: string) => void;
     errLog: (msg: string) => void;
     label: string;
   },
 ): Promise<WeixinInboundMediaOpts> {
   const { cdnBaseUrl, saveMedia, log, errLog, label } = deps;
+  const subdir = deps.subdir ?? "inbound";
   const result: WeixinInboundMediaOpts = {};
 
   if (item.type === MessageItemType.IMAGE) {
@@ -61,7 +64,7 @@ export async function downloadMediaFromItem(
             `${label} image-plain`,
             img.media.full_url,
           );
-      const saved = await saveMedia(buf, undefined, "inbound", WEIXIN_MEDIA_MAX_BYTES);
+      const saved = await saveMedia(buf, undefined, subdir, WEIXIN_MEDIA_MAX_BYTES);
       result.decryptedPicPath = saved.path;
       logger.debug(`${label} image saved: ${saved.path}`);
     } catch (err) {
@@ -83,12 +86,12 @@ export async function downloadMediaFromItem(
       logger.debug(`${label} voice: decrypted ${silkBuf.length} bytes, attempting silk transcode`);
       const wavBuf = await silkToWav(silkBuf);
       if (wavBuf) {
-        const saved = await saveMedia(wavBuf, "audio/wav", "inbound", WEIXIN_MEDIA_MAX_BYTES);
+        const saved = await saveMedia(wavBuf, "audio/wav", subdir, WEIXIN_MEDIA_MAX_BYTES);
         result.decryptedVoicePath = saved.path;
         result.voiceMediaType = "audio/wav";
         logger.debug(`${label} voice: saved WAV to ${saved.path}`);
       } else {
-        const saved = await saveMedia(silkBuf, "audio/silk", "inbound", WEIXIN_MEDIA_MAX_BYTES);
+        const saved = await saveMedia(silkBuf, "audio/silk", subdir, WEIXIN_MEDIA_MAX_BYTES);
         result.decryptedVoicePath = saved.path;
         result.voiceMediaType = "audio/silk";
         logger.debug(`${label} voice: silk transcode unavailable, saved raw SILK to ${saved.path}`);
@@ -113,7 +116,7 @@ export async function downloadMediaFromItem(
       const saved = await saveMedia(
         buf,
         mime,
-        "inbound",
+        subdir,
         WEIXIN_MEDIA_MAX_BYTES,
         fileItem.file_name ?? undefined,
       );
@@ -136,7 +139,7 @@ export async function downloadMediaFromItem(
         `${label} video`,
         videoItem.media.full_url,
       );
-      const saved = await saveMedia(buf, "video/mp4", "inbound", WEIXIN_MEDIA_MAX_BYTES);
+      const saved = await saveMedia(buf, "video/mp4", subdir, WEIXIN_MEDIA_MAX_BYTES);
       result.decryptedVideoPath = saved.path;
       logger.debug(`${label} video: saved to ${saved.path}`);
     } catch (err) {
diff --git a/src/messaging/process-message.ts b/src/messaging/process-message.ts
index c102af5..7df047f 100644
--- a/src/messaging/process-message.ts
+++ b/src/messaging/process-message.ts
@@ -60,8 +60,8 @@ function extractTextBody(itemList?: import("../api/types.js").MessageItem[]): st
 }
 
 /**
- * Process a single inbound message: route → download media → dispatch reply.
- * Extracted from the monitor loop to keep monitoring and message handling separate.
+ * Process a single inbound message: resolve route → download media → authorize → dispatch reply.
+ * Route is resolved first so agentId can isolate media per-agent in the media store.
  */
 export async function processOneMessage(
   full: WeixinMessage,
@@ -107,6 +107,35 @@ export async function processOneMessage(
     );
   }
 
+  // Resolve agent route early so we can use agentId for per-agent media isolation.
+  const senderId = full.from_user_id ?? "";
+  const route = deps.channelRuntime.routing.resolveAgentRoute({
+    cfg: deps.config,
+    channel: "openclaw-weixin",
+    accountId: deps.accountId,
+    peer: { kind: "direct", id: senderId },
+  });
+  logger.debug(
+    `resolveAgentRoute: agentId=${route.agentId ?? "(none)"} sessionKey=${route.sessionKey ?? "(none)"} mainSessionKey=${route.mainSessionKey ?? "(none)"}`,
+  );
+  if (!route.agentId) {
+    logger.error(
+      `resolveAgentRoute: no agentId resolved for peer=${senderId} accountId=${deps.accountId} — message will not be dispatched`,
+    );
+  }
+
+  if (debug) {
+    debugTrace.push(
+      "── 路由 ──",
+      `│ route: agent=${route.agentId ?? "none"} session=${route.sessionKey ?? "none"}`,
+    );
+  }
+
+  // Per-agent media isolation: wecom/<agentId>/inbound
+  const mediaSubdir = route.agentId
+    ? `wecom/${route.agentId}/inbound`
+    : "inbound";
+
   const mediaOpts: WeixinInboundMediaOpts = {};
 
   // Find the first downloadable media item (priority: IMAGE > VIDEO > FILE > VOICE).
@@ -145,6 +174,7 @@ export async function processOneMessage(
     const downloaded = await downloadMediaFromItem(mediaItem, {
       cdnBaseUrl: deps.cdnBaseUrl,
       saveMedia: deps.channelRuntime.media.saveMediaBuffer,
+      subdir: mediaSubdir,
       log: deps.log,
       errLog: deps.errLog,
       label,
@@ -166,8 +196,6 @@ export async function processOneMessage(
   const rawBody = ctx.Body?.trim() ?? "";
   ctx.CommandBody = rawBody;
 
-  const senderId = full.from_user_id ?? "";
-
   const { senderAllowedForCommands, commandAuthorized } =
     await resolveSenderCommandAuthorizationWithRuntime({
       cfg: deps.config,
@@ -208,30 +236,9 @@ export async function processOneMessage(
 
   if (debug) {
     debugTrace.push(
-      "── 鉴权 & 路由 ──",
+      "── 鉴权 ──",
       `│ auth: cmdAuthorized=${String(commandAuthorized)} senderAllowed=${String(senderAllowedForCommands)}`,
     );
-  }
-
-  const route = deps.channelRuntime.routing.resolveAgentRoute({
-    cfg: deps.config,
-    channel: "openclaw-weixin",
-    accountId: deps.accountId,
-    peer: { kind: "direct", id: ctx.To },
-  });
-  logger.debug(
-    `resolveAgentRoute: agentId=${route.agentId ?? "(none)"} sessionKey=${route.sessionKey ?? "(none)"} mainSessionKey=${route.mainSessionKey ?? "(none)"}`,
-  );
-  if (!route.agentId) {
-    logger.error(
-      `resolveAgentRoute: no agentId resolved for peer=${ctx.To} accountId=${deps.accountId} — message will not be dispatched`,
-    );
-  }
-
-  if (debug) {
-    debugTrace.push(
-      `│ route: agent=${route.agentId ?? "none"} session=${route.sessionKey ?? "none"}`,
-    );
     debugTs.preDispatch = Date.now();
   }
   // Propagate the resolved session key into ctx so dispatchReplyFromConfig uses