16. core.use

core.use composes a plan-facing recipe into a plan.

Conceptually:

core.use = compose a recipe into a plan

Allowed caller:

plan

Allowed target:

recipe

core.use must not target:

plan
fragment

core.use must not be called from:

recipe
fragment

Example:

core.use "Prepare service" {
  recipe "prepare-service"

  inputs {
    env inputs.env
  }

  capture {
    result -> locals.prepare_result
  }
}

16.1 Reference Semantics

The recipe field contains a host-resolved recipe reference.

KAL defines only the semantic requirement:

the reference must resolve to exactly one recipe component

The concrete reference form and resolution mechanism are host-defined.

If the recipe reference cannot be resolved, resolves ambiguously, or resolves to a non-recipe component, validation must fail.

16.2 Input Binding

core.use passes values into the recipe through an explicit inputs block.

Recipe inputs are not implicitly read from the caller.

The caller must bind required recipe inputs unless defaults exist.

Bindings for undeclared recipe input keys fail validation.

Extra caller-provided inputs are not allowed in the current draft.

16.3 Capture Behavior

Recipe outputs are not merged implicitly into caller scope.

Recipe output names become core.use capture sources.

Caller-side result handling uses the common capture model.

Uncaptured recipe outputs are discarded.

16.4 Composition Rule

A plan is the only layer that composes recipes.

This ensures that high-level workflow structure remains visible at the plan level.

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