fix(feishu): skip empty-text messages with no media to prevent blank session turns (#74634) (#74661)

Feishu delivers empty-text events (e.g. {"text":""}) when users send
blank messages or when a media-only message produces no text content.
Writing a blank user turn to the session file causes downstream LLM
providers such as MiniMax to reject requests with:

  invalid params, messages must not be empty (2013)

Guard at the point after media resolution: if ctx.content.trim() is
empty AND mediaList is empty, log the skip and return without queuing
a reply. This preserves all existing behaviour for text, media, and
mixed messages.

Regression test: dispatch a DM with {"text":""} (no media), assert
mockDispatchReplyFromConfig is not called.

Closes #74634. Thanks @xdengli.

CHANGELOG.md

@@ -48,6 +48,7 @@ Docs: https://docs.openclaw.ai
 - Agents/output: drop copied inbound metadata-only assistant replay turns before provider replay instead of synthesizing a placeholder, so Telegram and other channels cannot receive `[assistant copied inbound metadata omitted]` as model output. Fixes #74745. Thanks @adamwdear and @Marvae.
 - Doctor/memory: suppress skipped embedding-readiness warnings for key-optional providers such as Ollama and LM Studio while preserving timeout and not-ready diagnostics. Fixes #74608 and #73882. Thanks @hclsys.
 - Channels/groups: preserve observe-only turn suppression for prepared dispatch paths and restore deprecated channel turn runtime aliases, so passive observer/group flows stay silent while older plugins keep compiling. Thanks @vincentkoc.
+- Feishu: skip empty-text messages (e.g. `{"text":""}`) that carry no media, so no blank user turn is written to the session and downstream LLM providers cannot reject the request with "messages must not be empty". (#74634) Thanks @xdengli and @hclsys.
 - Feishu/Bitable: clean up newly created placeholder rows whose fields contain only default empty values while preserving meaningful link, attachment, user, number, boolean, and location values during create-app cleanup. (#73920) Carries forward #40602. Thanks @boat2moon.
 - macOS app: keep attach-only mode and the Debug Settings launchd toggle marker-only, so launching with `--attach-only`/`--no-launchd` no longer uninstalls the Gateway LaunchAgent or drops active sessions. (#72174) Thanks @DolencLuka.
 - Plugin SDK: restore the deprecated `plugin-sdk/zalouser` command-auth facade so published Lark/Zalo plugins that import it load on current hosts. Fixes #74702. Thanks @Goron01.

extensions/feishu/src/bot.test.ts

@@ -2999,4 +2999,42 @@ describe("handleFeishuMessage command authorization", () => {
     await Promise.all([dispatchMessage({ cfg, event }), dispatchMessage({ cfg, event })]);
     expect(mockDispatchReplyFromConfig).toHaveBeenCalledTimes(1);
   });
+
+  it("skips empty-text messages with no media to prevent blank user turns in session (#74634)", async () => {
+    // Feishu can deliver { "text": "" } events (empty-text or media-stripped
+    // messages). Writing blank user content to the session causes downstream
+    // LLM providers such as MiniMax to reject requests with "messages must not
+    // be empty". The handler should drop such events before queuing a reply.
+    mockShouldComputeCommandAuthorized.mockReturnValue(false);
+
+    const cfg: ClawdbotConfig = {
+      channels: {
+        feishu: {
+          dmPolicy: "open",
+          allowFrom: ["*"],
+        },
+      },
+    } as ClawdbotConfig;
+
+    const event: FeishuMessageEvent = {
+      sender: {
+        sender_id: {
+          open_id: "ou-empty-text-sender",
+        },
+      },
+      message: {
+        message_id: "msg-empty-text-74634",
+        chat_id: "oc-dm",
+        chat_type: "p2p",
+        message_type: "text",
+        // Feishu encodes empty text as {"text":""}
+        content: JSON.stringify({ text: "" }),
+      },
+    };
+
+    await dispatchMessage({ cfg, event });
+
+    // No reply should be dispatched: empty message is silently skipped
+    expect(mockDispatchReplyFromConfig).not.toHaveBeenCalled();
+  });
 });

extensions/feishu/src/bot.ts

@@ -859,6 +859,19 @@ export async function handleFeishuMessage(params: {
       log,
       accountId: account.accountId,
     });
+    // Skip messages with no text content and no media attachments. Feishu can
+    // deliver empty-text events (e.g. `{"text":""}`) when a user sends a blank
+    // message or when media parsing produces an empty string. Writing a blank
+    // user turn to the session causes downstream LLM providers (e.g. MiniMax)
+    // to reject the request with "messages must not be empty" errors. Logging
+    // the skip avoids silent loss without polluting the agent session.
+    if (!ctx.content.trim() && mediaList.length === 0) {
+      log(
+        `feishu[${account.accountId}]: skipping empty message (no text, no media) from ${ctx.senderOpenId}`,
+      );
+      return;
+    }
+
     const mediaPayload = buildAgentMediaPayload(mediaList);
     const audioTranscript = await resolveFeishuAudioPreflightTranscript({
       cfg: effectiveCfg,