How to Authenticate AI Agents in B2B SaaS: Delegated Auth, Scoped Tokens, and Audit Trails

Let's start with a scenario that should sound familiar. You've shipped an AI agent inside your B2B SaaS product. It summarizes meetings, drafts content, creates notes in Notion, and manages knowledge workflows — all on behalf of your users. It's fast. It's delightful. Your customers love it. Now ask yourself: when your agent creates a Notion page on behalf of John from XCorp — does Notion's API actually know it's John? Does it know it's XCorp? Does it know the agent is only supposed to write to specific workspaces and not read everything John has ever written? If your answer involves a shared API key, a service account with broad permissions, or a vague "we trust the agent to behave" — this article is for you. How Most Teams Handle Agent Auth Today (And Why It's a Liability) Most teams building customer-facing AI agents have stitched together authentication in one of three ways. They all work in development. They all carry risk that doesn't surface until something goes wrong in product