diff --git a/scripts/pkm_utils.py b/scripts/pkm_utils.py
index 1ea3c8a..f901701 100644
--- a/scripts/pkm_utils.py
+++ b/scripts/pkm_utils.py
@@ -106,17 +106,28 @@ def run_applescript_inline(script: str) -> str:
 
 
 def llm_generate(prompt: str, model: str = "mlx-community/Qwen3.5-35B-A3B-4bit",
-                 host: str = "http://localhost:8800") -> str:
+                 host: str = "http://localhost:8800", json_mode: bool = False) -> str:
     """MLX 서버 API 호출 (OpenAI 호환)"""
     import requests
+    messages = []
+    if json_mode:
+        messages.append({"role": "system", "content": "You must respond ONLY with valid JSON. No thinking, no explanation, no markdown."})
+    # Qwen3.5: /nothink 접미사로 thinking 출력 억제
+    messages.append({"role": "user", "content": prompt + " /nothink"})
     resp = requests.post(f"{host}/v1/chat/completions", json={
         "model": model,
-        "messages": [{"role": "user", "content": prompt}],
+        "messages": messages,
         "temperature": 0.3,
         "max_tokens": 1024,
     }, timeout=120)
     resp.raise_for_status()
-    return resp.json()["choices"][0]["message"]["content"]
+    content = resp.json()["choices"][0]["message"]["content"]
+    # JSON 블록 추출 (```json ... ``` 감싸기 대응)
+    if "```json" in content:
+        content = content.split("```json")[1].split("```")[0].strip()
+    elif "```" in content:
+        content = content.split("```")[1].split("```")[0].strip()
+    return content
 
 
 # 하위호환 별칭
diff --git a/tests/test_classify.py b/tests/test_classify.py
index df15367..13ffee6 100644
--- a/tests/test_classify.py
+++ b/tests/test_classify.py
@@ -10,7 +10,7 @@ import sys
 from pathlib import Path
 
 sys.path.insert(0, str(Path(__file__).parent.parent / "scripts"))
-from pkm_utils import ollama_generate, PROJECT_ROOT
+from pkm_utils import llm_generate, PROJECT_ROOT
 
 PROMPT_TEMPLATE = (PROJECT_ROOT / "scripts" / "prompts" / "classify_document.txt").read_text()
 
@@ -54,7 +54,7 @@ def run_classify_test(doc: dict) -> dict:
     prompt = PROMPT_TEMPLATE.replace("{document_text}", doc["text"])
 
     try:
-        response = ollama_generate(prompt)
+        response = llm_generate(prompt, json_mode=True)
         result = json.loads(response)
 
         db_match = result.get("domain_db") == doc["expected_db"]