Sierra is a conversational AI platform that businesses use to deploy customer-facing agents. A single agent handles conversations across chat, SMS, WhatsApp, email, voice and ChatGPT, resolving service requests and supporting revenue-generating interactions on the company's behalf.

Key features:

Ghostwriter builds agents from SOPs, transcripts, whiteboard photos, audio recordings or a plain-English goal.
Multilingual, multichannel agents with built-in guardrails.
Automated agent updates based on flagged issues.
Explorer for deep-research-style analysis of conversations.
Proactive conversation monitoring and multivariate experiments.
Traces of every tool call and knowledge lookup.

Sierra is aimed at large consumer brands and enterprises with high customer service volumes, and teams can build agents with or without engineering support. It uses outcome-based pricing, so companies pay for completed results. Access is arranged through the Sierra team rather than self-serve signup.