Answer · Agents & Automation

What AI models does Sierra use?

Sierra runs on Claude (Anthropic), GPT-5 class (OpenAI) and Sierra Agent OS 2.0 (Sierra), and routes requests between them.

Models used
3
Primary model
Claude
Public API
Yes
Last checked
2026-09-11

Model claims are labelled by how we know them: Claude — disclosed, GPT-5 class — disclosed and Sierra Agent OS 2.0 — unknown. "Disclosed" means the vendor says so in public; "inferred" means it was derived from documentation, headers or release notes.

Context window: Model-dependent.

Other stack signals: Pinecone and Plaid.

Cite this answer

Tomorrow. “What AI models does Sierra use?” Tomorrow AI & Emerging Tech Index, AlienSquad, updated 2026-09-11. https://tomorrow.aliensquad.ai/q/what-models-does-sierra-use

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