Implementation Guide
Secure AI agent API access by reducing capability before adding autonomy.
The safest starting point is not “give the agent the API key.” Start by deciding exactly which API capabilities the agent needs, then constrain identity, permissions, runtime context, and change management around that minimal set.
Step 1
Inventory the operations that could become tools.
List each operation the agent may call. Separate read, write, destructive, privileged, financial, object-access, and sensitive-data behavior. Do not treat “API access” as one permission when the actual operations have very different consequences.
Capability Mapper is designed for this contract-level inventory. The result is still descriptive: a documented operation is not proof of runtime reachability.
Step 2
Apply least privilege to operations, permissions, and data.
Remove operations the agent does not need. Prefer permission labels that match the job rather than broad administrative grants. Treat destructive and high-value actions as separate decisions.
Operation scope
Expose only endpoints required for the workflow.
Permission scope
Use the narrowest practical authorization alternative for each operation.
Data scope
Limit records and sensitive fields at runtime.
Step 3
Verify authentication and authorization as separate controls.
Authentication establishes identity. Authorization determines whether that identity may perform a specific action on a specific resource. A documented bearer token does not prove object-level or function-level authorization.
Review OpenAPI Security Requirement Objects, operation-level overrides, declared scopes, and whether an empty alternative can make authentication optional. Then verify effective runtime policy independently.
API authentication security → · BOLA and object authorization →
Step 4
Put high-impact actions behind runtime guardrails.
Contract analysis cannot enforce transaction ceilings, human approval, environment isolation, rate limits, network policy, or agent behavior. Use runtime controls for properties that exist only during execution.
Runtime controls
Approval for destructive actions, per-agent budgets, resource ownership checks, outbound allowlists, short-lived credentials, audit logs, and environment separation.
Fail closed on uncertainty
If the contract cannot be fully evaluated or runtime context is unknown, keep the decision in review instead of interpreting missing evidence as safety.
Step 5
Gate capability drift when the API changes.
A safe integration can become risky when a pull request adds a destructive endpoint, relaxes documented authorization, expands sensitive data, or changes the capability surface. Compare the approved baseline and candidate contract in CI.
API security in CI/CD → · AI agent API security model →