A startup lawyer vibe-coded an AI version of himself

• Synthesia sells software that helps businesses make videos with digital avatars.
• The company's general counsel recently used its tech to create a virtual lawyer for his department.
• The hard part, the GC said, is teaching the avatar how to behave like a credible human lawyer.

The newest "lawyer" at the artificial intelligence startup Synthesia doesn't have a law degree, a bar card, or a pulse.

The company, valued at $4 billion in January, sells software that helps businesses make videos with digital avatars for corporate training and marketing. Now one of its own executives is using that same technology to bulk up its legal department.

Gabe Stern, Synthesia's general counsel, said he built a legal AI avatar designed to chat with any prospective customer's legal and procurement teams.

Synthesia handles a high volume of contracts, Stern said. The biggest time sink is not marking up contracts. It's everything around it: scheduling calls, answering repetitive questions, and talking through points with the other side's counsel.

The legal avatar is still in private testing, but Stern said the idea is to let the avatar handle the early rounds of negotiation, or at least get the conversation rolling before a human lawyer steps in.

"Essentially, I've tried to recreate an effective lawyer," he said.

The project is yet another example of "vibe coding," the trend of non-engineers using AI tools to build software by describing what they want in plain language. What once required a team of developers can now be prototyped by a lawyer in a number of days.

Stern said it took him about two weeks to create the first prototype using the company's low-code platform and a custom version of OpenAI's ChatGPT. "I'm not a programmer," he said. Now, he could construct an agent in hours.

Stern is also part of a broader shift among in-house lawyers, who have become some of the profession's most eager adopters of generative artificial intelligence. Unlike law firms, which still make money by the hour, corporate lawyers are usually judged on how quickly they can get to a yes. Many already use tools to draft documents, compare contract terms, or summarize rules.

Lex machina

On a Zoom call, Stern shared his screen to show me how it works. First, Stern's video avatar greeted me. The plaid shirt and stubble were convincing enough; the giveaway was the hands, which kept cycling through the same gesture.

The avatar then introduced Willow, another avatar, which would guide me through Synthesia's master subscription agreement, the contract that sets the basic terms of service. "Don't worry," Fake Stern said, "all discussions with this agent are under NDA."

During the demo, Willow spoke with a slight delay, but with authority. It fielded real-time questions about security and liability. When pressed on Synthesia's liability cap — the maximum it would have to pay if something went wrong under the contract — Willow gently probed for the concern behind the ask, then pushed back on a demand for unlimited damages.

Under the hood, Stern said, Willow pulls from a closed body of internal and public-facing materials, including company policies, template contracts, and playbooks that spell out Synthesia's preferred negotiating positions.

Stern said he doesn't know of any legal startup building something like a legal avatar. (Synthesia competes with HeyGen and Colossyan for creating videos with avatars.) In his view, any business could create its own version of Willow with Synthesia's tech.

Long-term, Stern wants to deploy the avatar as another set of hands for Synthesia's small legal department and to help them practice negotiations. It also doubles as a live product demo for the prospective customer's lawyers and procurement teams using it.

The hard part, Stern said, is trying to teach the avatar how to behave like a credible human lawyer. Right now, it relies mainly on voice cues and tone, while a real lawyer can read the room or have a gut feel on how to best close out an issue or deal.

A Synthesia spokesperson says the next version of the tech will be able to detect visual cues like eye contact and body language. Still, there's no surrogate for the real deal.

Stern is the first to acknowledge that not everyone will be Willow's fan. Some early tech adopters and efficiency hounds may appreciate being able to get straight to the point with an avatar. Others, he said, will be frustrated and want a human counterparty who can offer a more white-glove experience.

"I think we're going to see it all," Stern said.

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