Quiz · Composing a Sandcastle request
A short knowledge check. Answers are hidden behind callouts so you can self-grade after answering.
1. In the academy story, who requests engineering work and who does it?
Crossplane requests engineering work — by causing a declarative EngineeringTask to exist that describes what construction the cluster wants done. Sandcastle does the work — by picking up the EngineeringTask, running an isolated agent, and returning a durable Git branch. Crossplane never writes Pico code, and Sandcastle never sees the original XR.
2. What are the two files that cross the compose → construct boundary?
xr-request.yaml— the compose-side input (the learner-authored Crossplane XR).engineering-task.yaml— the compose-side output and the construct-side input (the declarative record of the work).
The durable branch the Sandcastle produces is the construct-side output, but it does not cross back into the compose side of this lesson — it becomes the input to Part 3 · Lesson 1 instead.
3. Why must the Sandcastle read the EngineeringTask instead of the original XR?
So the Sandcastle stays independent of the XR shape. If a later Composition starts translating a different XR kind into the same task shape, the Sandcastle keeps working without modification. Coupling the Sandcastle to the XR would collapse the compose → construct boundary and force the construction layer to reason about composition concerns.
4. What does parametric on the request mean in this lesson?
The construction stage’s output depends on the request’s inputs, not on hard-coded strings in the agent. Concretely: change spec.value in the XR, and the greeting in the durable branch’s rules/hello.yaml changes to match — without editing any script. The runnable verify.sh asserts this end-to-end.
5. Why is it safe to dispose of the sandbox after the Sandcastle finishes, even though the EngineeringTask file lived inside it?
Because the same artifact-boundary guarantee from Part 1 · Lesson 1 still holds: only committed Git content crosses out of the sandbox. The EngineeringTask file was construction-side scratch state — its provenance information is redundant with spec.requestedBy on the compose-side task, which lives durably on the compose side. Reviewers who want to trace the branch back to its XR use that compose-side record, not the disposed copy inside the sandbox.