Strength
Authentication is machine-readable
Stripe's key model tells the agent which environment it is in and lets operators narrow authority with restricted keys.
The `sk_test_` and `sk_live_` prefixes expose environment directly in the credential. Restricted keys make least-privilege flows native instead of bolted on later. That combination reduces setup ambiguity and keeps the first automation boundary legible.
Agents do not need an extra config lookup to understand environment, and operators can scope the credential to a smaller payment surface before the model acts.
Evidence: Stripe secret key prefixes, restricted key model, and programmatic credential lifecycle in the Stripe platform.