Sierra Launches Self-Service AI Agent Builder, Targeting Mid-Market Customer Support
Sierra, the $10 billion AI startup led by former Salesforce CEO Bret Taylor, released Ghostwriter on March 25, a tool that lets businesses build customer service agents by describing workflows in plain English-without engineering teams.
The tool accepts standard operating procedures, call transcripts, and whiteboard sketches as input, then generates production-ready agents across voice, chat, and email in more than 30 languages. Sierra charges only when agents fully resolve customer issues, aligning its revenue with actual performance outcomes.
Why This Matters for Customer Support Teams
Building custom AI agents has required months of engineering work and dedicated staff. Ghostwriter compresses that into a conversation, making AI for Customer Support accessible to companies that couldn't afford bespoke deployments.
Sierra already serves 40% of the Fortune 50. With Ghostwriter, the company is moving from high-touch, hand-built deployments toward a self-service model that targets mid-market customers.
How Ghostwriter Works
Users describe their customer service workflows in natural language or upload existing documentation. Ghostwriter assembles a working agent and includes a sandboxed testing environment before deployment.
The tool operates as a continuous improvement loop: it analyzes real customer interactions, identifies where agents underperform, validates improvements in a sandbox, and ships updates automatically. Sierra calls this an "agent assembly line" that compounds quality over time.
Sierra's Agent Data Platform combines customer conversation data-from chats, emails, calls, and texts-with internal billing and transaction data. This gives agents persistent memory from past interactions, so they start conversations with context rather than from scratch.
The company takes a model-agnostic approach, drawing on AI models from OpenAI, Anthropic, and Google rather than locking customers into a single provider.
Proven Track Record at Scale
Existing deployments show what Ghostwriter could deliver widely. Rocket Mortgage's Sierra-powered agent refinances mortgages in about 30 minutes, compared to several hours over multiple days previously. Ramp's agents handled 90% of support requests without human involvement as of late 2025.
Sierra had more than 300 employees as of November 2025, with clients including ADT, Chime, Nordstrom, Nubank, Rivian, and SiriusXM. Over half of Sierra's customers had annual revenue above $1 billion, underscoring traction in accounts where switching costs are high.
A Crowded Field
Sierra faces direct competition from OpenAI's Frontier platform, Salesforce's Agentforce (which reached an estimated $800 million in annual recurring revenue), and Glean's enterprise agents.
Each competitor occupies a distinct position. Salesforce embeds agents inside CRM software. Glean targets internal knowledge workers. OpenAI supplies both the underlying models and deploys enterprise agents directly with Forward Deployed Engineers. Ghostwriter carves out its own lane by focusing on rapid deployment of customer-facing agents for companies without dedicated AI engineering teams.
According to Gartner, 40% of enterprise applications will embed task-specific AI agents by the end of 2026. The agentic AI market reached $10.9 billion in 2026 and is growing at roughly 40% annually, according to Fortune Business Insights.
The Self-Service Question
Whether Ghostwriter can match the quality of hand-built agents at software scale remains uncertain. A rival customer service company executive told Forbes in November 2025: "The big question is durability. I foresee a great philosophical war between us and Sierra."
Sierra was on track to exceed $100 million in annualized revenue by the end of its fiscal year in January 2026, according to a source familiar with the company's performance. Taylor and Sierra's co-founder and President Clay Bavor each own roughly one-quarter of the company, making both billionaires following the company's September 2025 funding round.
Sierra is making Ghostwriter available to new customers immediately. The outcomes-based pricing model ensures the company has a direct financial incentive to make those agents work. How quickly Ghostwriter closes the gap between automated and hand-built agents will determine whether the self-service gambit pays off.
For customer support teams, the tool tests whether AI Agents & Automation can reduce manual work while maintaining service quality-without requiring internal AI expertise.
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