APIs now encode the laws of physics for AI agents: the legal state transitions, not just the available functions.

• The UI used to constrain the state machine. Onboarding showed one screen, a small set of legal moves, then the next. Invalid transitions simply weren't rendered.
• Take the UI away and those guardrails have to move into the API: given the current state, what can happen next, what is invalid, and what information is missing?
• An agent-native API is therefore partly API, partly state machine, partly onboarding flow. It makes the legal moves legible to the agent.
• That matters enormously for CRM and financial systems, where agents need safe state changes rather than arbitrary function calls.
• ERP is the harder version: the data model is manageable, but business rules, approvals and industry-specific workflows make the state machine much richer.

• #agents
• #api-design
• #erp
• #mcp
• #state-machines