diff --git a/pymupdf4llm_mcp/app.py b/pymupdf4llm_mcp/app.py
index 2a62581..acbf2fc 100644
--- a/pymupdf4llm_mcp/app.py
+++ b/pymupdf4llm_mcp/app.py
@@ -1,3 +1,4 @@
+import os
 from pathlib import Path
 from typing import Annotated, Any
 
@@ -5,7 +6,9 @@
 from mcp.server.fastmcp import FastMCP
 from pydantic import Field
 
-mcp = FastMCP("pymupdf4llm-mcp")
+# Fix: Set environment variable and explicit log level to prevent validation error
+os.environ.setdefault('LOG_LEVEL', 'INFO')
+mcp = FastMCP("pymupdf4llm-mcp", log_level='INFO')
 
 
 @mcp.tool(
@@ -73,4 +76,4 @@ def convert_pdf_to_markdown(
         return {
             "error": f"Failed to convert PDF to markdown: {e!s}",
             "success": False,
-        }
+        }
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