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AI Agent API Security

AI agent API security is about controlling capability, not just credentials.

When an AI agent receives API tools, it receives the ability to perform real operations. Security begins by understanding those operations as capabilities, then deciding which should be available and under what conditions.

01Agent ↔ API boundary

A credential is only one part of the access decision.

The meaningful unit is the capability created by an operation plus its permissions and data context.

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capability financial · write
decision REVIEW
02Three questions

Map, review, then gate.

MAP — What could the agent do?

Inventory operations and classify access, risk, authentication, permission, and sensitive-data context.

REVIEW — What needs attention?

Combine capability inventory with contract-level security signals and explicit coverage.

GATE — What changed?

Compare the approved baseline with the candidate contract so capability expansion is visible in CI.

03Least privilege

Give the agent the smallest useful capability set.

Limit operations, permission alternatives, environments and high-impact actions rather than relying only on a narrow token.

04Static versus runtime

Contract analysis can narrow the question, not finish it.

OpenAPI does not prove live IAM enforcement, prompt-injection resistance, tool-selection behavior, network isolation, transaction limits, or production reachability.

Boundary

Use contract evidence before integration, then verify runtime controls separately. A favorable static result is not a production safety guarantee.