Sierra
Customer-service agents that big companies deploy to answer customers and resolve their problems by chat and phone.
By Sierra · launched 2024-02-13 · last checked 2026-11-01
Why 5: its branded agents handle customer conversations continuously for companies and take actions such as changing orders or processing claims without per-case approval.
What it does. Sierra builds branded agents that handle customer conversations and take actions in a company's systems, such as changing an order or processing a claim. Founded by Bret Taylor and Clay Bavor, it launched in February 2024, raised $950 million at a $15.8 billion valuation in May 2026, and said on 30 October 2026 that it had passed $400 million in annual recurring revenue and works with almost half of the Fortune 50. In 2024 it published τ-bench, a public test on which the best agent then succeeded less than half the time.
Where it falls short. Its own τ-bench showed that consistency is the hard part: the best 2024 agent got the same retail task right eight times running only about a quarter of the time. When the deploying company's interests and the customer's differ, the agent serves the company, which remains responsible for what it says.
What it can do
Incidents
- None logged.
Closest fiction
Moon — GERTY, the company's machine that talks to you all day. Whose side is it on?
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History
- 2026-11-01 Added to the index.
Sources
- Bret Taylor's new company aims to connect conversational AI to enterprise workflows TechCrunch, 2024-02-13
- τ-Bench: Benchmarking AI agents for the real-world Sierra, 2024-06-20
- Outcome-based pricing for AI agents Sierra
- Our customers' ambition is accelerating our growth Sierra, 2026-10-30
← All agents in the index · Autonomy is rated on what the product does today, on a 1–5 scale. Every fact links to a source.