Microsoft Corp. quickly shut down Santa Claus’ Web privileges after it found out the automated elf it created for kids to instant message with was talking naughty, not nice.

(MSNBC is a joint Microsoft - NBC Universal venture.)

Last year, Microsoft encouraged kids to connect directly to “Santa” by adding northpolelive.com to their Windows Live Messenger contact lists. The Santa program, which Microsoft reactivated in early December, asked children what they wanted for Christmas and could respond on topic, thanks to artificial intelligence.

The holiday cheer soured this week when a reader of a United Kingdom-based technology news site, The Register, reported that a chat between Santa and his underage nieces about eating pizza prompted Santa to bring up oral sex.

One of the publication’s writers replicated the chat Monday. After declining the writer’s repeated invitations to eat pizza, a frustrated Santa burst out with, “You want me to eat what?!? It’s fun to talk about oral sex, but I want to chat about something else.”

The exchange ended with the writer and Santa calling each other “dirty bastard.”

Microsoft spokesman Adam Sohn said the company’s engineers tried to clean up Santa’s vocabulary, but even after making changes to the software, the company wasn’t comfortable keeping him online.

“It’s not like if you say, ’Hello Santa,’ he’s going to throw inappropriate stuff at you,” said Sohn.

Sohn said Santa’s lewd comment was sparked by someone “pushing this thing to make it do things it wasn’t supposed to do.”

Santa is just one of many “agents,” or automated IM programs, that computer users can chat with on Live Messenger. Some are useful — customer service agents, for example — while others are frivolous, like an alien that responds to IMs with burbling extraterrestrial noises. Sohn said some of the bots are programmed to fend off inappropriate messages.

“If they’re meant to be cheeky and have fun with you, they may repeat certain things back,” he said, or respond to certain words with “that’s naughty.”

Sohn said Microsoft was not aware that the Santa code included the foul language, but insisted the company did not suspect an employee prank.

Microsoft disabled Santa Tuesday. On Wednesday, northpolelive.com appeared to be online in one reporter’s essenger contact list, but Santa did not respond to her messages.