diff --git a/extensions/feishu/src/reply-dispatcher.test.ts b/extensions/feishu/src/reply-dispatcher.test.ts
index d4527cc26..412bff70c 100644
--- a/extensions/feishu/src/reply-dispatcher.test.ts
+++ b/extensions/feishu/src/reply-dispatcher.test.ts
@@ -185,6 +185,23 @@ describe("createFeishuReplyDispatcher streaming behavior", () => {
     expect(sendMarkdownCardFeishuMock).not.toHaveBeenCalled();
   });
 
+  it("suppresses internal block payload delivery", async () => {
+    createFeishuReplyDispatcher({
+      cfg: {} as never,
+      agentId: "agent",
+      runtime: {} as never,
+      chatId: "oc_chat",
+    });
+
+    const options = createReplyDispatcherWithTypingMock.mock.calls[0]?.[0];
+    await options.deliver({ text: "internal reasoning chunk" }, { kind: "block" });
+
+    expect(streamingInstances).toHaveLength(0);
+    expect(sendMessageFeishuMock).not.toHaveBeenCalled();
+    expect(sendMarkdownCardFeishuMock).not.toHaveBeenCalled();
+    expect(sendMediaFeishuMock).not.toHaveBeenCalled();
+  });
+
   it("uses streaming session for auto mode markdown payloads", async () => {
     createFeishuReplyDispatcher({
       cfg: {} as never,
diff --git a/extensions/feishu/src/reply-dispatcher.ts b/extensions/feishu/src/reply-dispatcher.ts
index 35440396c..96338c343 100644
--- a/extensions/feishu/src/reply-dispatcher.ts
+++ b/extensions/feishu/src/reply-dispatcher.ts
@@ -192,6 +192,12 @@ export function createFeishuReplyDispatcher(params: CreateFeishuReplyDispatcherP
         void typingCallbacks.onReplyStart?.();
       },
       deliver: async (payload: ReplyPayload, info) => {
+        // FIX: Filter out internal 'block' reasoning chunks immediately to prevent
+        // data leak and race conditions with streaming state initialization.
+        if (info?.kind === "block") {
+          return;
+        }
+
         const text = payload.text ?? "";
         const mediaList =
           payload.mediaUrls && payload.mediaUrls.length > 0
@@ -209,7 +215,7 @@ export function createFeishuReplyDispatcher(params: CreateFeishuReplyDispatcherP
         if (hasText) {
           const useCard = renderMode === "card" || (renderMode === "auto" && shouldUseCard(text));
 
-          if ((info?.kind === "block" || info?.kind === "final") && streamingEnabled && useCard) {
+          if (info?.kind === "final" && streamingEnabled && useCard) {
             startStreaming();
             if (streamingStartPromise) {
               await streamingStartPromise;