Struct NodeDescribe 

pub struct NodeDescribe {
    pub type: NodeTypeStr,
    pub status: NodeStatus,
    pub value: Option<DescribeValue>,
    pub sentinel: Option<bool>,
    pub deps: Vec<String>,
    pub operator_kind: Option<String>,
    pub meta: Option<Value>,
}

Per-node descriptor.

JSON-shape disambiguation (D279, 2026-05-22, E-ii.3 — Rust ↔ TS parity)

Sentinel-vs-JSON-null disambiguation matches the TS describeNode shape (packages/pure-ts/src/core/meta.ts DescribeNodeOutput { value?: unknown, sentinel?: boolean }):

• Sentinel cache (cache == NO_HANDLE AND status == NodeStatus::Sentinel) → value key omitted from JSON; sentinel: true present.
• Legitimate JSON-null user value (DescribeValue::Rendered(Value::Null) under crate::Graph::describe_with_debug) → "value": null present; sentinel key omitted.
• Any other value → "value": <v> present; sentinel key omitted.

Pre-D279 the Rust shape diverged: value: None (sentinel) and value: Some(DescribeValue::Rendered(Value::Null)) (rendered null) both serialized to "value": null — JSON-indistinguishable. #[serde(skip_serializing_if = "Option::is_none")] on both value and sentinel enforces the converged TS-shape. Rust additionally always emits status (TS makes it optional via includeFields); the sentinel flag is redundant for Rust consumers that check status == "sentinel", but its presence preserves cross-impl shape parity (cross-track-ledger §2 row 2026-05-22).

Fields

type: NodeTypeStr

"state" / "derived" / "dynamic" / "producer".

status: NodeStatus

Lifecycle status (canonical Appendix B enum).

value: Option<DescribeValue>

Current cache value. None when sentinel (NO_HANDLE); omitted from serialized JSON via skip_serializing_if (D279).

sentinel: Option<bool>

D279 (2026-05-22): explicit sentinel discriminator matching TS’s sentinel?: boolean field. Some(true) when status == NodeStatus::Sentinel; None otherwise (omitted from JSON via skip_serializing_if).

deps: Vec<String>

Dep names in declaration order (_anon_<NodeId> for unnamed).

operator_kind: Option<String>

Operator discriminant (e.g. "map"); None for non-operators.

meta: Option<Value>

Free-form metadata per canonical Appendix B. Always None in this slice (metadata-storage primitive not yet shipped).

Trait Implementations

impl Clone for NodeDescribe

fn clone(&self) -> NodeDescribe

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for NodeDescribe

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

Formats the value using the given formatter.

impl Serialize for NodeDescribe

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.