diff --git a/lightrag/llm/anthropic.py b/lightrag/llm/anthropic.py
index 62f439d7a9..60b8ad9d73 100644
--- a/lightrag/llm/anthropic.py
+++ b/lightrag/llm/anthropic.py
@@ -104,6 +104,9 @@ async def anthropic_complete_if_cache(
         )
     kwargs.pop("response_format", None)
     timeout = kwargs.pop("timeout", None)
+    # Anthropic requires this, while LightRAG callers usually don't pass it.
+    kwargs.setdefault("max_tokens", 8192)
+    stream_requested = kwargs.pop("stream", False)
 
     anthropic_async_client = (
         AsyncAnthropic(
@@ -129,7 +132,12 @@ async def anthropic_complete_if_cache(
     verbose_debug(f"System prompt: {system_prompt}")
 
     try:
-        create_params = {"model": model, "messages": messages, "stream": True, **kwargs}
+        create_params = {
+            "model": model,
+            "messages": messages,
+            "stream": stream_requested,
+            **kwargs,
+        }
         if system_prompt:
             create_params["system"] = system_prompt
         response = await anthropic_async_client.messages.create(**create_params)
@@ -160,6 +168,19 @@ async def anthropic_complete_if_cache(
         )
         raise
 
+    if not stream_requested:
+        # Non-streaming: return the plain string LightRAG's KG pipeline expects.
+        content_blocks = getattr(response, "content", None) or []
+        text_parts = [
+            getattr(block, "text", "")
+            for block in content_blocks
+            if getattr(block, "type", None) == "text"
+        ]
+        text = "".join(text_parts)
+        if r"\u" in text:
+            text = safe_unicode_decode(text.encode("utf-8"))
+        return text
+
     async def stream_response():
         try:
             async for event in response:
diff --git a/tests/test_anthropic_llm.py b/tests/test_anthropic_llm.py
new file mode 100644
index 0000000000..f30b408853
--- /dev/null
+++ b/tests/test_anthropic_llm.py
@@ -0,0 +1,118 @@
+from __future__ import annotations
+
+import asyncio
+import importlib
+import sys
+from types import ModuleType, SimpleNamespace
+
+import pytest
+
+
+class _FakeAnthropicError(Exception):
+    pass
+
+
+class _FakeMessages:
+    def __init__(self, calls: list[dict], response):
+        self._calls = calls
+        self._response = response
+
+    async def create(self, **kwargs):
+        self._calls.append(kwargs)
+        return self._response
+
+
+class _FakeStream:
+    def __init__(self, chunks: list[str]):
+        self._chunks = chunks
+
+    async def __aiter__(self):
+        for chunk in self._chunks:
+            yield SimpleNamespace(delta=SimpleNamespace(text=chunk))
+
+
+def _load_anthropic_module(monkeypatch, response):
+    calls: list[dict] = []
+    clients: list[dict] = []
+
+    class FakeAsyncAnthropic:
+        def __init__(self, **kwargs):
+            clients.append(kwargs)
+            self.messages = _FakeMessages(calls, response)
+
+    fake_pm = SimpleNamespace(is_installed=lambda name: True, install=lambda name: None)
+    fake_tenacity = SimpleNamespace(
+        retry=lambda **_kwargs: lambda func: func,
+        stop_after_attempt=lambda *_args, **_kwargs: None,
+        wait_exponential=lambda *_args, **_kwargs: None,
+        retry_if_exception_type=lambda *_args, **_kwargs: None,
+    )
+    fake_anthropic = ModuleType("anthropic")
+    fake_anthropic.AsyncAnthropic = FakeAsyncAnthropic
+    fake_anthropic.APIConnectionError = _FakeAnthropicError
+    fake_anthropic.RateLimitError = _FakeAnthropicError
+    fake_anthropic.APITimeoutError = _FakeAnthropicError
+
+    monkeypatch.setitem(sys.modules, "pipmaster", fake_pm)
+    monkeypatch.setitem(sys.modules, "tenacity", fake_tenacity)
+    monkeypatch.setitem(sys.modules, "anthropic", fake_anthropic)
+    sys.modules.pop("lightrag.llm.anthropic", None)
+
+    return importlib.import_module("lightrag.llm.anthropic"), calls, clients
+
+
+@pytest.mark.offline
+def test_anthropic_non_streaming_returns_text_and_default_max_tokens(
+    monkeypatch,
+):
+    response = SimpleNamespace(
+        content=[
+            SimpleNamespace(type="text", text="hello"),
+            SimpleNamespace(type="tool_use", text="ignored"),
+            SimpleNamespace(type="text", text=" world"),
+        ]
+    )
+    anthropic_module, calls, clients = _load_anthropic_module(monkeypatch, response)
+
+    result = asyncio.run(
+        anthropic_module.anthropic_complete_if_cache(
+            model="claude-test",
+            prompt="hi",
+            api_key="test-key",
+            response_format={"type": "json_object"},
+        )
+    )
+
+    assert result == "hello world"
+    assert clients[-1]["api_key"] == "test-key"
+    assert calls[-1]["stream"] is False
+    assert calls[-1]["max_tokens"] == 8192
+    assert "response_format" not in calls[-1]
+
+
+@pytest.mark.offline
+def test_anthropic_streaming_path_stays_opt_in(monkeypatch):
+    anthropic_module, calls, _ = _load_anthropic_module(
+        monkeypatch,
+        _FakeStream(["hello", " world"]),
+    )
+
+    async def run_case():
+        stream = await anthropic_module.anthropic_complete_if_cache(
+            model="claude-test",
+            prompt="hi",
+            api_key="test-key",
+            stream=True,
+            max_tokens=128,
+        )
+
+        chunks = []
+        async for chunk in stream:
+            chunks.append(chunk)
+        return chunks
+
+    chunks = asyncio.run(run_case())
+
+    assert "".join(chunks) == "hello world"
+    assert calls[-1]["stream"] is True
+    assert calls[-1]["max_tokens"] == 128