Struct Node 

pub struct Node {
    pub id: NodeId,
    pub ntype: String,
    pub summary: Option<String>,
    pub props: BTreeMap<String, Ipld>,
    pub content: Option<Bytes>,
    pub context_sentence: Option<String>,
    pub extra: BTreeMap<String, Ipld>,
}

A graph vertex.

See SPEC §4.1 and the module docs. Construct via Node::new and add properties with the with_* fluent helpers.

Sparse embeddings live in the per-commit sidecar (Commit.sparse Prolly tree, keyed by NodeCid) rather than inline on Node. This keeps sparse bytes out of the canonical Node hash so vocabulary differences or encoder-version changes cannot perturb NodeCid. Legacy DAG-CBOR carrying an explicit sparse_embed map round-trips losslessly through the extra flatten sink, keeping NodeCids stable.

Fields

id: NodeId

Stable node identity. Survives content edits; edges reference this.

ntype: String

Free-form node-type label ("Person", "mnem:Class", …).

summary: Option<String>

Optional short natural-language summary. Intended as the token-cheap representation of this node for LLM-facing retrieval: the field agents read when assembling context under a token budget. Distinct from props (structured) and content (opaque payload).

props: BTreeMap<String, Ipld>

Property map. Values are any DAG-CBOR value, including Links.

content: Option<Bytes>

Optional opaque payload (a document body, a file, …).

context_sentence: Option<String>

Optional contextualized-chunk prefix. An LLM-generated one-sentence placement cue (“This paragraph is from Section 3 of a legal contract between Alice and Bob’s employer…”) stored alongside the node. The ingest pipeline prepends it to summary before embedding so the dense + sparse lanes capture positional and relational context the chunk alone would lose.

Anthropic’s 2024 Contextual Retrieval paper reports -49% to -67% retrieval-failure reduction when this prefix is present; mnem stores it on the node so the render path can surface it back to the agent for faithful source attribution.

Additive: existing nodes with context_sentence = None keep byte-identical CIDs (same skip_serializing_if = "Option::is_none" pattern as other optional fields).

extra: BTreeMap<String, Ipld>

Forward-compat extension map per SPEC §3.2 - holds fields this version doesn’t recognize and preserves them on re-encode so signed Nodes remain verifiable across version upgrades. Legacy sparse_embed fields written before G17 land here and round-trip byte-identically.

Implementations

impl Node

pub const KIND: &'static str = "node"

The _kind discriminator for nodes. "node" on the wire.

pub const DEFAULT_NTYPE: &'static str = "Node"

Default ntype value used when a caller wants to ingest a node without choosing a category. Applied by the HTTP bulk/single handlers when the caller omits label or sends an empty string. Direct Rust callers of Node::new still pass ntype explicitly; Node::new_default is the zero-arg convenience.

pub fn new(id: NodeId, ntype: impl Into<String>) -> Self

Construct a Node with no summary, no props, no content.

pub fn new_default(id: NodeId) -> Self

Construct a Node with the project default ntype = "Node". Convenience for callers that don’t want to categorise on write; equivalent to Node::new(id, Node::DEFAULT_NTYPE).

pub fn with_summary(self, summary: impl Into<String>) -> Self

Attach a short summary. Returns self for chaining.

pub fn with_prop(self, key: impl Into<String>, value: impl Into<Ipld>) -> Self

Attach a property. Returns self for chaining.

pub fn with_content(self, content: Bytes) -> Self

Attach opaque content.

pub fn with_context_sentence(self, context: impl Into<String>) -> Self

Attach an LLM-generated contextualized-chunk prefix . The render path prepends this to the summary so the agent sees where this chunk sits in its source document.

Typical callers run this at ingest time via a TextGenerator from mnem-llm-providers with a prompt like:

“Give a single sentence that situates the following chunk within its source so a retrieval model can understand where it came from. Chunk: {summary} Document context: {doc_title}”

pub fn get_str(&self, key: &str) -> Option<&str>

Get a property as &str. Returns None if absent or not a string.

pub fn get_int(&self, key: &str) -> Option<i128>

Get a property as i128. Returns None if absent or not an integer.

pub fn get_bool(&self, key: &str) -> Option<bool>

Get a property as bool. Returns None if absent or not a bool.

pub fn get_float(&self, key: &str) -> Option<f64>

Get a property as f64. Returns None if absent or not a float.

pub fn get_bytes(&self, key: &str) -> Option<&[u8]>

Get a property as a byte slice. Returns None if absent or not bytes.

Trait Implementations

impl Clone for Node

fn clone(&self) -> Node

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Node

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for Node

fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error>

Deserialize this value from the given Serde deserializer.

impl PartialEq for Node

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for Node

fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error>

Serialize this value into the given Serde serializer.

impl Eq for Node

impl StructuralPartialEq for Node