Sierra unveils Agent OS models Curie and Fleming at its summit, with the platform handling compliance, voice latency and cost automatically
Synopsis
At its San Francisco summit, Sierra announced two new Agent OS models, Curie and Fleming, alongside Tandem Voice, Persona Studio and Ghostwriter. Curie powers the core orchestration loop of a conversation, deciding which path to follow, which tools to call and what replies customers see; Fleming detects when a caller is another agent, so businesses can handle bots and fraud. Sierra says Agent OS automatically ensures compliance, low-latency voice and a better cost basis, leaving companies to focus on building their own agent.
Interpretation
Sierra added two task-specific models to Agent OS, separating conversation orchestration from caller identification. Agent OS previously relied on fine-tuned models such as Linnaeus and Darwin to understand customer questions and surface answers in milliseconds; the new models bring orchestration and bot detection into the same model family. Sierra announced at the summit that Curie powers the core orchestration loop and Fleming detects when the caller on the phone is another agent, enabling businesses to handle bots and fraud.
Tandem Voice lets a voice agent think fast and slow at once: a conversation layer responds in real time while a reasoning layer uses the full audio and transcript to map the path forward. Voice is where latency and quality are most noticeable, and while the reasoning layer decides what to do, the agent can tell the customer it is checking on an order, keeping the conversation moving. Sierra describes the conversation layer hearing and responding in real time while the reasoning layer uses the full audio and text transcript underneath.
Persona Studio lets businesses upload their own voice samples and tune an agent's personality directly in Agent Studio, with no engineering or AI expertise required. Sierra says one large subscription business saw its resolution rate improve by over 50% after deploying Voice Personas. That figure comes from Sierra's description of one unnamed large subscription business, offered to show the business impact of voice personality.
Perspective
This report covers the products and partnerships Sierra announced at its summit, including Curie, Fleming, Tandem Voice, Persona Studio, Ghostwriter, Horizon and the Stripe integration; these are vendor announcements, not independent evaluation results.
Sierra says one large subscription business improved its resolution rate by over 50% after deploying Voice Personas, but gives no name, baseline or measurement method for that business; the actual performance of Curie and Fleming is likewise described only by the vendor.