# `connection.package_unknown`

Connection names no provider package the app holds.

Area 11, [External services](../topics/external-services.md); not declinable; the next step is usually the agent's.

A connection names a provider package the app holds, by its name and
version; a library package needs no connection at all:






```jadpo
application {
    connections: {
        couriers: {
            package: AcmeCouriers.v2
            domains: [shipping]
            environment: config.couriers_environment
        }
    }
}
```

```text
error: `couriers` connects to `AcmeCouriers.v2`, which the app doesn't hold
 --> app.jadpo:4:22
  |
4 |             package: AcmeCouriers.v2
  |                      ^^^^^^^^^^^^^^^ no such package
  reason: A connection's `package:` names a provider package by its name and version, installed in `packages/` or the app's own in `shared/providers/`; the app holds `AcmeCouriers.v1`.
  next: Write `package: AcmeCouriers.v1` (agent)
  rule: connection.package_unknown
  help: https://jadpo.dev/docs/errors/connection.package_unknown

check failed: 1 error, 6 files
```