Two gaps in the control vocabulary, both found by reading back what 0a331c7
actually shipped against what it claimed.
**`kind: enum` worked and was undocumented.** The whole point of that kind is
that a node author can declare a control without touching the interface, and
ops/README.md is where a node author looks. A kind absent from the table is one
nobody will use. It is now in the table, with the property that makes it cheap
spelled out: the value is the chosen index carried as an `f32` like every other
parameter, so a uniform expression can read it, the sidecar stores it
unchanged, and nothing along the way needed a second kind of value.
**A declared node could not ask for a widget at all.** `Presentation` gained an
ordered preference list and a demand, and `tone_curve` and `framing` use them —
but both are hand-written Rust. A YAML node had no way to say that several of
its parameters form one control, so the generated half of the pipeline was
locked out of the half of FR-DEV-3a that makes widgets extensible. Nodes now
take a `presentation:` block:
presentation:
widgets: [colour_wheel]
demand: { two_dimensional: true }
params: [hue, strength]
`demand` carries exactly two flags and there is deliberately no key for a pixel
width, a breakpoint or a platform name — those are the frontend's to decide,
and ARCH §4.3a is explicit that a core reasoning about them will eventually be
wrong about a display it never saw.
Widget names are spelled in the YAML the way `WidgetKind` spells them, so a
declaration and descriptor.rs cannot drift into two vocabularies for one idea,
and an unknown one is a build error listing the six that exist. `params:` is
checked against the node's own parameters: the widget claims what it names and
the generic path skips what was claimed, so a typo would silently drop a
parameter out of *both* — the one mistake here that produces no error and no
control.
Verified by declaring a presentation on a node, confirming the generated
`fn presentation` matched, and confirming both error paths report the file and
the key; then reverted, since no node in the chain wants a widget yet.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
dtourolleandClaude Opus 5
23f0c4b76a