Fix errors being sent as HTML and rename 'start' to 'serve'

Author: mrexodia

README.md

@@ -44,7 +44,7 @@ def greet(
     return f"Hello, {name}!"
 
 if __name__ == "__main__":
-    mcp.start("127.0.0.1", 8000)
+    mcp.serve("127.0.0.1", 8000)
 ```
 
 Then manually test your MCP server with the [inspector](https://github.com/modelcontextprotocol/inspector):

src/zeromcp/mcp.py

@@ -62,6 +62,13 @@ def log_message(self, format, *args):
         """Override to suppress default logging or customize"""
         pass
 
+    def send_error(self, code, message=None, explain=None):
+        self.send_response(code)
+        self.send_header("Content-Type", "text/plain")
+        self.send_header("Access-Control-Allow-Origin", "*")
+        self.end_headers()
+        self.wfile.write(f"{message}\n".encode("utf-8"))
+
     def handle(self):
         """Override to add error handling for connection errors"""
         try:
@@ -204,7 +211,7 @@ def __init__(self, name: str):
     def tool(self, func: Callable) -> Callable:
         return self.tools.method(func)
 
-    def start(self, host: str, port: int):
+    def serve(self, host: str, port: int):
         if self.running:
             print("[MCP] Server is already running")
             return