85% of Client Briefs Are AI-Written and Agency Leaders Are Fed Up

By Tom Whitfield

M&C Saatchi's North American CEO, Nadja Bellan-White, estimates that 85% of the briefs clients send her agency are now written with AI tools — and she says the industry is approaching a breaking point. "It's a tipping point… It's a little bit ridiculous," she told the Digiday Media Buying Summit last week.

The result is corporate documents that run hundreds of pages, packed with jargon and empty of vision. "How many times can you say 'framework' in one sentence? How many times can you try 'economies of scale'? How many times can you tell me I need this to 'tie back to commercial objectives'?" Bellan-White asked.

How widespread is AI brief writing?

Brief writing has become one of generative AI's most common uses in marketing. A Basis Technologies survey conducted between July and August found 56.4% of marketers and agencies now use the technology to build strategy, media or campaign creative briefs.

The applications run across the industry:

• Media agencies deploy AI agents to suggest audience segments, analyze competitors' media plans or recommend search keywords to bid on.
• Creative shops and influencer agencies use it to speed through consumer research, brand guidelines and economic trends.
• In-house teams at high-spending brands use generative tools to spin up strategy approaches.
• Publishers use agentic tools that answer client briefs with AI-generated insights.

Staffers praise the hours saved. Behind closed doors, they complain about the cost.

What are the complaints?

Speaking under Chatham House rules at a DMBS townhall, one agency executive said: "I've seen some of the worst briefs I've ever seen in my career recently, and it's because they're so disjointed and there's no through-line on what… the marketing goal is."

Another put it more bluntly: "AI is making it worse. It's pontificating on a sentence structure that makes [a brief] 10 pages long."

Complaints about bloated memos predate AI. At the start of the decade, a cross-industry initiative even pushed for better brief writing. But as another agency executive framed the current problem: "There's a lack of critical thinking."

Is there a cognitive cost?

Academics call the pattern "cognitive offloading" — delegating knowledge work to a machine. A 2025 MIT Media Lab study measured the brainwaves of students writing essays unaided versus with search engines or ChatGPT. The AI-assisted group showed a 55% reduction in brainwave activity.

The financial toll is measurable too. A GWI survey of 150 British marketers published last month found 29% admitted that inaccurate or misleading AI-generated insights had cost their companies money. Bloated documents also steal time from colleagues and clients, and loose attitudes toward AI-conjured statistics demand closer-than-usual supervision by fact-checkers.

"They have exported all of their thinking to AI," said Tony Russo, vp of innovation and strategy at indie agency Mile Marker, during another DMBS session. "It's a judgment problem."

What is the fix?

Christina Riccitelli, chief innovation and analytics officer at media agency OpAD, said managers should step in when junior staff lean too hard on AI. "You have to reel them back in," she said.

Bellan-White went further: "Turn off your laptop. Just literally shut it down. Turn off your phones. I want you to look me in the eye and actually have a conversation. Do you know how uncomfortable that is for people today? Because if you actually have to have a conversation, that means you actually have to know what you're talking about."

She allows that AI "can be a good sparring partner," but insists the final call stays human. "At the end of the day, you need to be the one to make the decision. You understand the client's briefs. You understand the market context. You've got to really think about what it is that's recommended."

With AI adoption still climbing and brain-drain evidence mounting, agencies that don't reassert human judgment risk paying for it in both billing hours and lost credibility.