The render context is now the live EXECUTION environment: host/blog--comp-ctx reads device
(mobile/desktop from User-Agent) and locale (from Accept-Language) PURELY from the request
headers — no perform — alongside auth + the graph-query resolver. So the SAME composition
object renders responsively/personalised: `(alt (when (eq "device" "mobile") …) …)` is a
responsive layout, `(when (eq "locale" "fr") …)` a localised variant. The object (its
when-variants) is the definition; the context picks which path renders.
host/blog--device-of / host/blog--locale-of; comp-ctx now (principal req) — post handler
passes req; /compose-demo gains a device-variant block. Reactive/live values plug into the
same context later with no new combinators (the plan's "make the context live" axis).
Verified via focused harness eval (mobile+fr vs desktop+en contexts render M/D variants;
no-req ctx omits device). Tests added.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>