# Caller authentication

Production accepts only RS256 JWTs verified against KeyCape JWKS with the exact
configured issuer and `approval-engine` audience. `exp`, `iat`, `sub`,
`principal_type`, `tenant`, `roles`, `scope`, and `assurance` are mandatory.
Missing or unverifiable credentials fail closed. The development static-token
mode is explicit, file-backed, and refused with `--production`.
The verified `tenant` must exactly match the service's configured store tenant;
cross-tenant reads and mutations are rejected before object lookup.

| Route | Required scope |
|---|---|
| create approval | `approval:create` |
| get approval or claim | `approval:read` |
| add approval entry | `approval:approve` |
| revoke | `approval:revoke` |
| supersede | `approval:supersede` |
| consume | `approval:consume` and service/agent principal |
| cadence, outbox, storage | `approval:observe` |
| explicit heartbeat | `approval:emit` |

Create additionally requires `binding.actor == sub`. Approval-entry subject,
assurance, and evidence reference are derived from the verified JWT, never the
request body. KeyCape owns client registration and scope grants; approval-engine
only verifies and enforces them. Requested registrations are:

- audience/resource server `approval-engine` with the scopes above;
- the secrets-engine PEP service client with `approval:read` and
  `approval:consume`;
- separately governed lifecycle/operator clients with only their needed
  mutation or observation scopes.

Client credentials belong in OpenBao/operator custody and must not be placed in
manifests, logs, State Hub, or this repository.