Basics built in, an external dependency brings full power

The rule. Every abcd capability ships with a basic form that works with no daemon and no dependency beyond the abcd binary and the operating system, and offers an opt-in adapter to an external dependency for the full form. The basic is never a stub: it does the job at the scale a single person or a small team hits first, and it keeps working when the adapter is absent. The adapter never becomes a precondition: a repository or a machine that declines it loses reach or speed, not the capability.

Why. abcd is for people who know what they want to build and need help shipping it; a capability that needs a broker, a service, or a network before it does anything is a capability most of them will never switch on, and a capability that only works through a vendor's cloud is one they cannot trust with their record. The basic form is also where the contract is discovered, which is the same reason the script-first MVP puts the first cut in a script: the on-disk shapes, the failure modes and the verbs worth having stabilise under real use before the adapter has to preserve them. And the adapter's cost is real: a running process, an authentication story, a second audit trail; it should be paid by the people who need what it buys, not by everyone.

Bounds.

• The basic form and the adapter share one record contract. What the basic writes as a file, the adapter mirrors as a file; a capability is never auditable in one form and opaque in the other.
• The adapter is host-agnostic in the same way the basic is: it depends on the external tool, never on a particular agent harness or a vendor's cloud. A local-network dependency qualifies; a hosted relay does not.
• "Basic" is measured at the user surface, not at the code: the test is whether a person with the binary alone can do the thing, not whether the code path is short.

Live instances. The oracle backends (host-delegated by default; native, CLI, API and MCP as opt-in adapters). The secret scanners (the native detector is the default; gitleaks and trufflehog are opt-in dependencies the install offers). The session mailbox (a shared-directory mailbox is the basic; an embedded broker is the adapter).

Promotion. This principle is the standing statement of the "host-delegated by default" boundary in the conventions, widened from LLM work to every external dependency. No enforcement hook exists; per the promotion path in this directory's README, it becomes a discipline-kind intent the moment one does.