Struct ContextItem 

pub struct ContextItem {
    pub source: ContextSourceKind,
    pub source_id: String,
    pub rank: usize,
    pub score: f64,
    pub text: String,
    pub estimated_chars: usize,
    pub provenance: Value,
    pub metadata: Value,
}

One ranked piece of context that may be packed into a bounded model window.

ContextItem is intentionally backend-neutral. Memory crates, MCP/resource adapters, and harnesses can all project their native records into this shape so tests can assert what context was selected, omitted, and rendered.

use rig_compose::{ContextItem, ContextSourceKind};

let item = ContextItem::new(
    ContextSourceKind::Memory,
    "profile/alice/location",
    "fact alice lives in Berlin",
)
.with_rank(0)
.with_score(9.5);

assert_eq!(item.estimated_chars, item.text.chars().count());

Fields

source: ContextSourceKind

Backend-neutral source category.

source_id: String

Stable id inside the source system.

rank: usize

Zero-based rank after source-local selection.

score: f64

Relevance score used for ordering within the source or planner.

text: String

Prompt-ready text.

estimated_chars: usize

Character count estimate for early context packing.

provenance: Value

Source-specific provenance such as frame id, URI, tool call id, or path.

metadata: Value

Caller-defined metadata not required for packing.

Implementations

impl ContextItem

pub fn new( source: ContextSourceKind, source_id: impl Into<String>, text: impl Into<String>, ) -> Self

Build a context item with a source, source id, and prompt-ready text.

pub fn with_rank(self, rank: usize) -> Self

Set the source-local rank used by ContextPack::pack.

pub fn with_score(self, score: f64) -> Self

Set the relevance score attached by the source or planner.

pub fn with_estimated_chars(self, estimated_chars: usize) -> Self

Override the character estimate when a caller has a better tokenizer or sizing approximation.

pub fn with_provenance(self, provenance: Value) -> Self

Attach source-specific provenance.

pub fn with_metadata(self, metadata: Value) -> Self

Attach caller-defined metadata.

Trait Implementations

impl Clone for ContextItem

fn clone(&self) -> ContextItem

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ContextItem

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for ContextItem

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for ContextItem

fn eq(&self, other: &ContextItem) -> 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 ContextItem

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

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for ContextItem