diff --git a/insta-lab/app/card_writer.py b/insta-lab/app/card_writer.py
new file mode 100644
index 0000000..a763e5f
--- /dev/null
+++ b/insta-lab/app/card_writer.py
@@ -0,0 +1,100 @@
+"""Claude로 10페이지 카드 카피를 한 번에 생성."""
+
+import json
+import logging
+import re
+from typing import Any, Dict, Optional
+
+from anthropic import Anthropic
+
+from .config import ANTHROPIC_API_KEY, ANTHROPIC_MODEL_SONNET
+from . import db
+
+logger = logging.getLogger(__name__)
+
+DEFAULT_ACCENT_BY_CATEGORY = {
+    "economy": "#0F62FE",
+    "psychology": "#A66CFF",
+    "celebrity": "#FF5C8A",
+}
+
+DEFAULT_PROMPT = """너는 인스타그램 카드 뉴스 카피라이터다.
+카테고리: {category}
+키워드: {keyword}
+참고 기사:
+{articles}
+
+10페이지 인스타 카드용 카피를 다음 JSON 한 객체로만 출력해라 (코드펜스 금지):
+{{
+  "cover_copy": {{"headline": "<훅 한 줄>", "body": "<서브카피 1~2줄>", "accent_color": "#hex"}},
+  "body_copies": [
+    {{"headline": "<포인트 헤드라인>", "body": "<2~4문장 본문>"}},
+    ... (총 8개)
+  ],
+  "cta_copy": {{"headline": "<요약 한 줄>", "body": "<마무리 1~2줄>", "cta": "팔로우/저장 등"}},
+  "suggested_caption": "<인스타 캡션 본문>",
+  "hashtags": ["#태그1", "#태그2", ...]
+}}
+"""
+
+
+def _client() -> Anthropic:
+    return Anthropic(api_key=ANTHROPIC_API_KEY)
+
+
+def _strip_codefence(s: str) -> str:
+    s = s.strip()
+    if s.startswith("```"):
+        s = re.sub(r"^```(?:json)?\s*|\s*```$", "", s).strip()
+    return s
+
+
+def _load_prompt() -> str:
+    pt = db.get_prompt_template("slate_writer")
+    if pt and pt.get("template"):
+        return pt["template"]
+    return DEFAULT_PROMPT
+
+
+def write_slate(keyword: str, category: str,
+                articles: Optional[list] = None) -> int:
+    """Claude로 10페이지 카피 생성 후 card_slates에 저장. slate_id 반환."""
+    if articles is None:
+        articles = db.list_news_articles(category=category, days=2)
+    article_text = "\n".join(
+        f"- {a['title']}: {a.get('summary', '')[:120]}" for a in articles[:8]
+    ) or "(참고 기사 없음)"
+
+    prompt = _load_prompt().format(category=category, keyword=keyword, articles=article_text)
+    msg = _client().messages.create(
+        model=ANTHROPIC_MODEL_SONNET,
+        max_tokens=4000,
+        messages=[{"role": "user", "content": prompt}],
+    )
+    raw = msg.content[0].text
+    cleaned = _strip_codefence(raw)
+    try:
+        data: Dict[str, Any] = json.loads(cleaned)
+    except json.JSONDecodeError as e:
+        logger.warning("slate JSON parse failed: %s", e)
+        raise ValueError(f"Invalid JSON from LLM: {e}") from e
+
+    body_copies = data.get("body_copies") or []
+    if len(body_copies) != 8:
+        raise ValueError(f"body_copies must have 8 items, got {len(body_copies)}")
+
+    cover = data.get("cover_copy") or {}
+    if not cover.get("accent_color"):
+        cover["accent_color"] = DEFAULT_ACCENT_BY_CATEGORY.get(category, "#222831")
+
+    sid = db.add_card_slate({
+        "keyword": keyword,
+        "category": category,
+        "status": "draft",
+        "cover_copy": cover,
+        "body_copies": body_copies,
+        "cta_copy": data.get("cta_copy") or {},
+        "suggested_caption": data.get("suggested_caption") or "",
+        "hashtags": data.get("hashtags") or [],
+    })
+    return sid
diff --git a/insta-lab/tests/test_card_writer.py b/insta-lab/tests/test_card_writer.py
new file mode 100644
index 0000000..a5263e0
--- /dev/null
+++ b/insta-lab/tests/test_card_writer.py
@@ -0,0 +1,75 @@
+import json
+import os
+import tempfile
+from unittest.mock import patch, MagicMock
+
+import pytest
+
+from app import db as db_module
+from app import card_writer
+
+
+@pytest.fixture
+def tmp_db(monkeypatch):
+    fd, path = tempfile.mkstemp(suffix=".db")
+    os.close(fd)
+    monkeypatch.setattr(db_module, "DB_PATH", path)
+    db_module.init_db()
+    yield path
+    import gc
+    gc.collect()
+    for ext in ("", "-wal", "-shm"):
+        try:
+            os.remove(path + ext)
+        except OSError:
+            pass
+
+
+SAMPLE_LLM_JSON = {
+    "cover_copy": {"headline": "금리 인상 단행", "body": "왜 지금?", "accent_color": "#0F62FE"},
+    "body_copies": [
+        {"headline": f"포인트 {i+1}", "body": f"본문 {i+1}"} for i in range(8)
+    ],
+    "cta_copy": {"headline": "정리", "body": "바로 확인", "cta": "팔로우"},
+    "suggested_caption": "금리에 대해 알아보자",
+    "hashtags": ["#금리", "#경제"],
+}
+
+
+def _fake_messages_create(*_args, **_kwargs):
+    msg = MagicMock()
+    block = MagicMock()
+    block.text = json.dumps(SAMPLE_LLM_JSON, ensure_ascii=False)
+    msg.content = [block]
+    return msg
+
+
+def test_write_slate_persists_full_payload(tmp_db, monkeypatch):
+    db_module.add_news_article({
+        "category": "economy", "title": "기준금리 인상 단행",
+        "link": "https://example.com/1", "summary": "한국은행 발표",
+    })
+    fake_client = MagicMock()
+    fake_client.messages.create = _fake_messages_create
+    monkeypatch.setattr(card_writer, "_client", lambda: fake_client)
+
+    sid = card_writer.write_slate(keyword="기준금리", category="economy")
+    slate = db_module.get_card_slate(sid)
+    assert slate["status"] == "draft"
+    body_copies = json.loads(slate["body_copies"])
+    assert len(body_copies) == 8
+    assert body_copies[0]["headline"] == "포인트 1"
+    assert json.loads(slate["cover_copy"])["accent_color"] == "#0F62FE"
+
+
+def test_write_slate_raises_on_invalid_json(tmp_db, monkeypatch):
+    fake_client = MagicMock()
+    bad_msg = MagicMock()
+    bad_block = MagicMock()
+    bad_block.text = "not json"
+    bad_msg.content = [bad_block]
+    fake_client.messages.create.return_value = bad_msg
+    monkeypatch.setattr(card_writer, "_client", lambda: fake_client)
+
+    with pytest.raises(ValueError):
+        card_writer.write_slate(keyword="x", category="economy")