OpenAI on Tuesday hit back at Elon Musk's lawsuit against the company, releasing a series of emails that shows him agreeing with the company's plan to raise more money and gradually move away from open-source releases of its products.

Why it matters: OpenAI says that, contrary to Musk's charges, it remains committed to its mission of achieving artificial general intelligence for humankind's good — but it also isn't going to take punches or cede moral high ground to Musk.

In a blog post, OpenAI uses e-mails from Musk — who co-founded the firm with a half-dozen others —to refute Musk's key claims and also make the case that Musk's views were closer to the company's than his suit suggests.

• For example, OpenAI says that Sam Altman and Greg Brockman had planned to raise $100 million but Musk suggested they raise more.
• "We need to go with a much bigger number than $100M to avoid sounding hopeless," Musk said in an e-mail, according to OpenAI's blog. "I think we should say that we are starting with a $1B funding commitment… I will cover whatever anyone else doesn't provide."
• In a separate email Musk said, "Even raising several hundred million won't be enough. This needs billions per year immediately or forget it."

Catch up quick: Musk's 35-page complaint alleges that OpenAI abandoned its founding agreement and partnered with Microsoft to commercialize its work.

Between the lines: OpenAI had already rebutted many of Musk's allegations in an internal memo from strategy chief Jason Kwon, which was seen by Axios, who insisted the company is not a "de facto subsidiary of Microsoft."

The intrigue: OpenAI co-founder Ilya Sutskever is listed as a co-author of the post, along with four others, including CEO Sam Altman and longtime company president Greg Brockman.

• Sutskever had broken with Altman during last November's boardroom battle at OpenAI, then did an about-face as he signed an employees' open letter demanding Altman's reinstatement. He remains an OpenAI employee but his role has been unclear since Altman returned as CEO.
• Altman said when he was rehired that the company was looking for a role for Sutskever. The company has offered no update since.

The big picture: The company is facing a host of legal challenges beyond Musk's suit.

• Musk is facing his own legal troubles, including a suit from four former Twitter executives alleging $128 million in unpaid severance.

Behind the scenes: "The closer people are to being pointed in the same direction, the more contentious the disagreements are. You see this in sects and religious orders," Altman told New York Times in December.

What's next: OpenAI says in the post that it intends to move in court to dismiss all of Musk's claims.

The bottom line:"We're sad that it's come to this," the OpenAI post says, "with someone whom we've deeply admired — someone who inspired us to aim higher, then told us we would fail, started a competitor, and then sued us when we started making meaningful progress towards OpenAI's mission without him."

Editors' note: This story is breaking news and will be updated.