diff --git a/apps/memos-local-plugin/core/llm/client.ts b/apps/memos-local-plugin/core/llm/client.ts
index 7749a572f..a53d0efdd 100644
--- a/apps/memos-local-plugin/core/llm/client.ts
+++ b/apps/memos-local-plugin/core/llm/client.ts
@@ -125,6 +125,21 @@ export function createLlmClientWithProvider(
     return [{ role: "system", content: systemInsert }, ...messages];
   }
 
+  function ensureJsonWordInUserMessage(messages: LlmMessage[]): LlmMessage[] {
+    const lastUserIdx = messages.map((m) => m.role).lastIndexOf("user");
+    if (lastUserIdx < 0) return [...messages, { role: "user", content: "Return valid json only." }];
+
+    const msg = messages[lastUserIdx];
+    if (/\bjson\b/i.test(msg.content)) return messages;
+
+    const out = messages.slice();
+    out[lastUserIdx] = {
+      ...msg,
+      content: `${msg.content}\n\nReturn valid json only.`,
+    };
+    return out;
+  }
+
   function buildCallInput(opts: LlmCallOptions | undefined, jsonMode: boolean): ProviderCallInput {
     return {
       temperature: opts?.temperature ?? config.temperature,
@@ -339,7 +354,7 @@ export function createLlmClientWithProvider(
   ): Promise<LlmCompletion> {
     const messages = normalizeMessages(input);
     const msgsWithJsonHint = opts?.jsonMode
-      ? inject(messages, buildJsonSystemHint())
+      ? ensureJsonWordInUserMessage(inject(messages, buildJsonSystemHint()))
       : messages;
     const call = buildCallInput(opts, opts?.jsonMode === true);
     const { completion } = await callWithFallback(msgsWithJsonHint, call, opts, opts?.op ?? "complete");
@@ -352,7 +367,7 @@ export function createLlmClientWithProvider(
   ): Promise<LlmJsonCompletion<T>> {
     const messages = normalizeMessages(input);
     const systemHint = buildJsonSystemHint(opts.schemaHint);
-    const msgs = inject(messages, systemHint);
+    const msgs = ensureJsonWordInUserMessage(inject(messages, systemHint));
     const call = buildCallInput(opts, true);
     const op = opts.op ?? "complete.json";
     const maxMalformedRetries = Math.max(0, opts.malformedRetries ?? 1);
diff --git a/apps/memos-local-plugin/tests/unit/llm/client.test.ts b/apps/memos-local-plugin/tests/unit/llm/client.test.ts
index cd5cf6106..d378e4bf6 100644
--- a/apps/memos-local-plugin/tests/unit/llm/client.test.ts
+++ b/apps/memos-local-plugin/tests/unit/llm/client.test.ts
@@ -95,12 +95,14 @@ describe("llm/client", () => {
     expect(fake.lastMessages).toEqual([{ role: "user", content: "hi there" }]);
   });
 
-  it("injects a json system hint when jsonMode=true", async () => {
+  it("injects json hints into system and user messages when jsonMode=true", async () => {
     const fake = new FakeProvider("openai_compatible", () => ({ text: '{"ok":1}', durationMs: 1 }));
     const client = createLlmClientWithProvider(cfg(), fake);
     await client.complete("do it", { jsonMode: true });
     expect(fake.lastMessages?.[0]?.role).toBe("system");
     expect(fake.lastMessages?.[0]?.content).toMatch(/single valid JSON value/i);
+    expect(fake.lastMessages?.at(-1)?.role).toBe("user");
+    expect(fake.lastMessages?.at(-1)?.content).toMatch(/valid json only/i);
     expect(fake.lastInput?.jsonMode).toBe(true);
   });
 
@@ -269,7 +271,9 @@ describe("llm/client", () => {
     expect(fake.lastMessages?.[0]?.role).toBe("system");
     expect(fake.lastMessages?.[0]?.content).toMatch(/You are strict\./);
     expect(fake.lastMessages?.[0]?.content).toMatch(/single valid JSON value/);
-    expect(fake.lastMessages?.[1]).toEqual({ role: "user", content: "go" });
+    expect(fake.lastMessages?.[1]?.role).toBe("user");
+    expect(fake.lastMessages?.[1]?.content).toMatch(/^go/);
+    expect(fake.lastMessages?.[1]?.content).toMatch(/valid json only/i);
   });
 
   it("rejects empty messages array", async () => {