Credential Brokering

Credential brokering is the pattern in which an intermediary fetches a credential from a vault or credential store at the moment of access and hands it to an already-authorized user or workload, instead of that user or workload holding the credential permanently. HashiCorp Boundary's documentation defines it this way and contrasts it with credential injection: brokering "returns credentials to the user", while injection "authenticates on the user's behalf without ever exposing the credential".

The distinction matters most for AI agents and other non-human identities. A brokered credential still reaches the client, so an agent that reads untrusted input can be steered into leaking or misusing it. Injection, or better, short-lived tokens issued for one audience (OAuth token exchange or ID-JAG), keeps the secret out of the agent's reach entirely. Brokering is still a large improvement over static API keys in config files, which is the failure behind several exposed-secret incidents and the static API key abuse technique. When evaluating a broker, ask whether the credentials it hands out are dynamic and short-lived, scoped to one target, and logged per session.

See also: secrets management, just-in-time access, HashiCorp Boundary, HashiCorp Vault, MCP authorization, securing AI agent identities