This is a story about traditions, dress codes, and brevity.

A year ago, Goldman Sachs was acting as if it were really two firms--at least terms of  how people dressed.

There was the traditionalist New York-dominated version, all frenetic activity, ambition to the point of cliche--and bespoke suits. 

And there was the San Francisco version, where there's "no sign on the door, no dress code, and kombucha" in the break room, as Dakin Campbell put it for Bloomberg in April. The accompanying photo for that article portrays a San Francisco Goldman executive lounging in gray t-shirt and jeans. 

The difference was supposed to allow the SF version of Goldman to embrace an aesthetic more like its California tech companies clients' vibe. But reportedly, it created a strain.

So this week, the firm's top leaders did something about it. They changed the dress code for the entire firm, and sent a very short email to every Goldman employee announcing the change.

The message itself runs only 130 words, which is amazing. I salute them for their editing powers. But when you parse it, the part laying out the dress code is even shorter: just 12 words, according to Bloomberg, which got the memo:

"[P]lease dress in a manner that is consistent with your clients' expectations."

That's really it, except for an additional minor, and ultimately unhelpful comment toward the end: "All of us know what is and is not appropriate for the workplace."

Because of course, we don't all agree on what is appropriate. That's why people have codes. (You can read the entire email  here. It won't take long.)

Yet, I digress. When I first heard about Goldman's new 12-word dress code, my immediate thought was of GM.

Because CEO Mary Bara used to be the vice president of global human resources at GM, and when she was in that role she pared its 10-page dress code document down to just two words: "Dress appropriately."

GM and GS are radically different, but they do have one important thing in common: a lengthy pedigree, and the kind of culture that comes with it.

GM traces its history to 1908; Goldman goes back even further, to 1869. You don't survive that long without a conservative streak -- meaning one that finds something that works and sticks with it.

But even the most staid corporate cultures are due for a little revolution now and again. And with 12 short words, Goldman's might be under way.

Let's just hope they don't all start wearing gray fleece vests, just because they no longer have to wear suits.