SANTA CLARA — You don’t need a secret code or a court order to talk football with Vic Fangio, who remains and probably shall forever be the 49ers’ straightest shooter.

You ask, he answers, no fudging or forceful evasions necessary for the 49ers’ indispensable defensive coordinator.

Even Jim Harbaugh knows not to ask Fangio a question he doesn’t want answered 100 percent candidly, Fangio said with shrug on Friday.

“Being blunt and being honest has gotten me in trouble some over the years,” Fangio said Friday during a break between practices, “but I do think in the long run it’s the best way to be.

“I don’t view my job as a cheerleader. I don’t view my job as a best friend, chest-bumping buddy.

“Players want to be coached and they want to be taught and I found that out a long time ago. And that’s what I do — I coach ’em and teach ’em.”

Coincidentally, at his regular news conference just a few minutes before our conversation, Fangio gave a prime example of his candid public commentary.

Asked about veteran cornerback Nnamdi Asomugha, Fangio tilted his head and offered a very mixed review of Asomugha’s performance in camp and his chances to make the team.

And yes, that kind of public give-and-take puts Fangio wholly alone among 49ers execs, assistants, who — led by Harbaugh, of course — usually offer as little information as possible and rely on gushing generalities for most cases.

But it also underlines Fangio’s unique and essential status, playing a tart version of the George Seifert role to Harbaugh’s Bill Walsh.

Fangio, 54, can speak his mind freely because he has earned it, because his personality and brain power command the 49ers defense, and because the offensive-minded Harbaugh is smart enough to let Fangio be Fangio.

Players accept the public comments, according to safety Donte Whitner, because it’s exactly what Fangio says to them behind closed doors.

“He doesn’t care if you’re Patrick Willis, he doesn’t care if you’re me, he doesn’t care if you’re (NaVorro) Bowman, he doesn’t care if you’re Justin (Smith) or Aldon (Smith),” Whitner said.

“If you do something wrong, he’s going to be the guy that straightens you out. … He’s a straight-shooter; he’ll tell Nnamdi (the same thing he said at the news conference) in the meeting room, to his face.”

It’s also part of the defensive-player mentality — tough defenses are usually created by tough-minded, unflinching defensive chiefs.

That’s what Fangio brought when he left a long career as an NFL assistant to join Harbaugh’s staff at Stanford four years ago, which coincided with the Cardinal defense turning into something substantial. (That’s when he got the nickname “Lord Fangio.”)

Harbaugh took Fangio with him to the 49ers in 2011, and as it was at Stanford, the defense is Fangio’s unquestioned domain, and now they’re in their fourth season together.

Fangio shrugged when I asked him if he saw any Harbaugh-Fangio parallels to the way Walsh and Seifert ran the 1980s 49ers dynasty, but he noted one similarity.

“One thing Bill Walsh did when he was the head coach, he still had a good feel for what it takes to play good defense,” Fangio said.

“And I think Jim has the same feel, too.”

That means something because Fangio didn’t have to say it, and because he said it you know he means it.

While Harbaugh’s message at the start of camp was to forget the successes and failures of the recent past, Fangio says he reminded his defenders that they let some things slip at the end of the 2012 run.

That includes, of course, the loss to Baltimore in the Super Bowl.

“I actually get a little more agitated about (the Super Bowl) now than I did the first week after the game,” Fangio said Friday. “I just think we could’ve played better.

“Does that mean we would’ve won the game? I don’t know. But we just did not play as well as we could’ve played and I wish we would have.”

Whitner offered up a general goal for 2013: The 49ers defense has to return to its stampeding ways of 2011, when it held opponents to 14.3 points per game and created a league-high 38 take-aways.

Last year, the 49ers defense held opponents to 17.1 points per game and had 25 take-aways.

“We have to get back to the way we played in 2011,” Whitner said.

Asked for his general thoughts on this unit, Fangio said the 49ers have two big question marks — who replaces departed free safety Dashon Goldson and injured nickel back Chris Culliver.

Otherwise, Fangio said he needs to see improvement across the board, even and especially from the stars.

That’s the only way great defenses stay great — or get better — and that’s how great, straight-shooting coordinators make sure of it.

Read Tim Kawakami’s Talking Points blog at blogs.mercurynews.com/kawakami. Contact him at tkawakami@ mercurynews.com.