Ina FriedClay Bavor and Bret Taylor with Ina Fried at Axios' AI+ Summit in San Francisco on Dec. 17, 2024. Photo: Chris Constantine/AxiosSierra, which builds custom AI agents for enterprise customer service, is nearing a deal for a $350 million financing round that values the two-year-old startup at $10 billion, a source tells Axios. Why it matters: AI agents have been hot all year but the industry hasn't yet settled on a clear path for building and deploying them. Sierra is betting on a special...