A long-anticipated courtroom battle between Elon Musk and Sam Altman kicked off in California Monday — and the legal brawl is poised to spill mounds of inside gossip and dirty laundry from Silicon Valley in the weeks ahead.

In addition to Musk and Altman, witnesses in the case — in which Musk has accused Altman’s OpenAI of breaking a pledge to share its technology openly as a nonprofit — include Shivon Zilis, who has been accused of spying on OpenAI as a former board member, even as she carried on a romance with Musk.

Among the evidence that OpenAI has cited is a text exchange between Musk and Zilis just before he quit OpenAI’s board in 2018. Zilis, who has borne several of Musk’s children, asked him whether she should stay “close and friendly” with OpenAI to “keep info flowing.”

“Close and friendly,” Musk replied, according to court documents. “But we are going to actively try to move three or four people from OpenAl to Tesla.”

US District Judge Yvonne Gonzalez Rogers ruled last month that Musk’s relationship with Zilis is “highly relevant to Zilis’s credibility and Zilis’s role as a conduit between Musk and OpenAI.”

Elsewhere, the judge has limited what the jury will hear in the trial, which conducted jury selection on Monday with opening arguments slated to begin Tuesday.

That includes allegations of Musk’s reported use of drugs including “rhino ketamine” — previously raised during depositions. The judge, howevever, did allow questioning about Musk’s attendance at the 2017 “Burning Man” festival despite objections from Musk’s attorneys, finding it relevant to whether he was fully engaged in key negotiations over OpenAI’s restructuring at the time.

Elsewhere, embarrassing court filings thus far include an incendiary text exchange between Musk and Mark Zuckerberg that was revealed in March, in which Meta’s CEO assured Musk that Meta was “on alert” to remove posts involving doxxing or threats.

After responding with a heart emoji, Musk asked Zuckerberg, “Are you open to the idea of bidding on the OpenAI IP with me and some others?” to which Zuckerberg replied, “Want to discuss live?”

Other messages that have surfaced ahead of the court case include a 2016 email exchange between Musk and Altman themselves, who — before Musk abandoned their partnership in 2018 just three years after they started it — discussed potential deals with other tech giants to secure computing power.

In one such exchange, Musk said he’d prefer to partner with Microsoft over Amazon because Bezos “is a bit of a tool”.

In another, Altman thanked Musk for his early support: “you’re my hero,” and adding that OpenAI might not have existed without him. “It really (expletive) hurts when you publicly attack OpenAI,” Altman added.

Musk apologized, but emphasized that “the fate of civilization is at stake.”

Other big names taking the stand could include Satya Nadella, CEO of Microsoft, which on Monday granted OpenAI more freedom to partner with its rivals following more than a year of contentious back-and-forth over Microsoft’s grip on the company.

In the suit, Musk alleges that Altman and his OpenAI co-founder Greg Brockman violated OpenAI’s original mission by shifting the company to a for-profit model to enrich themselves. Musk has vowed to donate proceeds from any judgement to charity.

OpenAI calls Musk’s lawsuit a case of sour grapes and is part of a “broader strategy of harassment aimed at slowing us down and advantaging his own AI company, xAI.”  

Other potential witnesses include Thinking Machines CEO Mira Murati, a former top engineer at OpenAI who had participated in Altman’s temporary ouster as CEO in 2023. Musk’s personal assistant and fixer Jared Birchall also may be called to the stand over accusations he filed paperwork to create for-profit incarnation of OpenAI.

“His own words and actions speak for themselves,” OpenAI said in court papers. “Elon not only wanted, but actually created, a for-profit as OpenAI’s proposed new structure.”