Enum Primitive 

pub enum Primitive {
    Tool(Tool),
    Resource(Resource),
    ResourceTemplate(ResourceTemplate),
    Prompt(Prompt),
}

Any primitive, tagged with its kind.

The four payloads stay separate types rather than collapsing into one struct with fourteen Option fields, because the fields that matter are not shared: Tool has an input schema and no uri, Resource has a uri and no input schema, and a single flat struct would let a resource be built with an input schema and no way to say whether that was a mistake.

Variants

Tool(Tool)

A tool.

Resource(Resource)

A resource.

ResourceTemplate(ResourceTemplate)

A resource template.

Prompt(Prompt)

A prompt.

Implementations

impl Primitive

pub const fn kind(&self) -> PrimitiveKind

Which list this belongs to.

pub const fn id(&self) -> &PrimitiveId

The key this primitive is filed under.

pub fn meta(&self) -> PrimitiveMeta

The metadata a visibility decision is made from.

Derived from the payload rather than stored beside it, so the two cannot disagree — a separate meta field would be a second source of truth for a thing the payload already determines.

What derives a requirement, and what does not

A requirement is raised when a session cannot correctly use the primitive without the feature. That is a narrower test than “the primitive has a field the revision does not define”, and the difference decides whether a feature is a gate or a filter.

A tool’s outputSchema is a gate. A tool that declares structured output answers with a structuredContent member, and a session that cannot represent it does not get a text fallback from the registry — it gets a result whose shape it will misread. This is the same StructuredContentToText decision the lowering path already made, and the registry has to agree with it or the two disagree about the same tool on the same session.

Annotations, icons, title and size are not gates. An older peer ignores a hint it does not recognise and the tool still works, which is the same reason Annotations does not raise required_features on a content block. Requiring a feature for decoration would hide a perfectly callable tool from every session on an older revision, and the hiding is silent — the peer simply never sees the tool.

Trait Implementations

impl Clone for Primitive

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Primitive

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl From<Primitive> for Registered

fn from(primitive: Primitive) -> Self

Converts to this type from the input type.

impl From<Prompt> for Primitive

fn from(prompt: Prompt) -> Self

Converts to this type from the input type.

impl From<Resource> for Primitive

fn from(resource: Resource) -> Self

Converts to this type from the input type.

impl From<ResourceTemplate> for Primitive

fn from(template: ResourceTemplate) -> Self

Converts to this type from the input type.

impl From<Tool> for Primitive

fn from(tool: Tool) -> Self

Converts to this type from the input type.

impl PartialEq for Primitive

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for Primitive