Sierra

Bret Taylor

@btaylor

We wrote up how we've AI-pilled Sierra. The centerpiece is an AI agent named Pinecone that the whole company uses for everything from business analysis to writing code. Pinecone now generates 70% of our PRs and automates hundreds of tasks every day to quietly handle work no one explicitly prompted. https://t.co/OlEnO6cTw5

Katelyn Lesse

@katelyn_lesse

sierra is another one of many eng teams building internal agentic software dev platforms. everyone doing this is working through hard architecture and infrastructure problems to achieve speed, reliability, and security. in this case, i think sierra is taking on more complexity than necessary to accomplish their goals. on architecture: they chose to make the runner the durable thing. and since a singleton has to survive, they needed a lot of machinery to let it sleep and then resurrect it: state machine lifecycle, checkpoint events, replay on wake. their output queue with checkpoints is a hibernation mechanism. they could have instead made the durable thing just a session log in a database. then the runner could die and recovery is much simpler - reprovision the sandbox and pick up from the session log. on infra: they mention avoiding sandbox vendors, but they went even further and avoided csp managed sandbox primitives too. agentcore runtime is per-session microvms with free idle cpu time, for example. even plain ec2 stop/start would accomplish most of hibernation but with a stronger boundary than their choice of hardened containers on a shared kernel. one choice they made that adds complexity that i think is good and necessary is credential injection via egress proxy. i haven’t seen a better way to avoid agents holding keys. it’s fascinating to see the proliferation of system design choices in this space. like harness inside the sandbox vs out, and how to manage state. it’s a good reminder that we’re still in the first inning of long running agents, and there’s so much more that’ll play out.

Bret Taylor

Co-founder & CEO

Co-creator of Google Maps and former CTO of Facebook and co-CEO of Salesforce, he chairs OpenAI's board and co-founded Sierra in 2023 as its CEO.

Clay Bavor

Co-founder

Spent 18 years at Google leading Google Labs, its AR/VR effort (Project Starline) and Google Lens before co-founding Sierra with Bret Taylor in 2023.

Aaron Barthel

RVP

Previously at Google · Columbia, South Carolina, United States

Joined May 2026

Rishi Mandal

Head of Platform Product

Previously at Future · San Francisco, California, United States

Joined May 2026

Jessie Seidler

Enterprise Sales Director

Previously at Sourcegraph · San Francisco, California, United States

Joined May 2026

Previously at Databricks · Boston, Massachusetts, United States

Joined May 2026