Not every API must be rebuilt; agents can work with well-documented, deterministic APIs, but workflows that alter financial or legal states or rely on unwritten rules require careful human-in-the-loop design.

A 2026 Salt Security survey shows nearly half of organizations lack visibility into machine traffic and almost half experience API-security delays in production, signaling governance lags adoption.

API governance must expand beyond authentication and rate limits to include action-level permissions, current state, structured responses, duplicate-action protection, full audit trails, and clear human approval points.

Poor design raises reconciliation costs, slows integrations, and erodes trust; platforms that embed identity, permissions, and auditability into the transaction will be more trustworthy for automation.

Agent readiness should be prioritized by inventorying capabilities, classifying by consequence, granting narrowly scoped identities, requiring human approval for high-impact actions, confirming current state, and investing in observability with immediate stop mechanisms.

APIs are becoming execution surfaces for AI agents, capable of independently choosing tools, sequencing actions, and pursuing goals.

Design APIs backward from business outcomes: expose current state, permission conditions, recovery paths, and ensure idempotency plus separation of preparation versus submission for high-risk actions.

Documentation must be machine-readable with schemas and structured errors so agents can interpret them without guessing.