Struct RecallMeta 

pub struct RecallMeta {
    pub recall_mode: String,
    pub reranker_used: String,
    pub candidate_counts: CandidateCounts,
    pub blend_weight: f64,
}

v0.6.3.1 (P3): per-request observability for the recall pipeline.

Surfaces which recall path actually ran, which reranker was active, the candidate pool sizes coming out of FTS and HNSW (before fusion), and the blend weight applied to the semantic component. Always present in memory_recall responses; older clients ignore unknown fields per the JSON-RPC convention.

Closes G2/G8/G11 from the v0.6.3 audit by making every silent-degrade path observable at request time. The capabilities surface (P1) reports the same state at startup; this struct is the per-call mirror.

Fields

recall_mode: String

Which recall path executed.

• "hybrid" — embedder + FTS, blended (G11 happy path).
• "keyword_only" — embedder unavailable or query-embed failed, keyword-only recall served (G11 silent-degrade now visible).

reranker_used: String

Which reranker scored the final ordering.

• "neural" — BERT cross-encoder (autonomous tier, model loaded).
• "lexical" — operator opted for the lexical variant, or the tier never asked for a neural cross-encoder.
• "degraded_lexical" — v0.7.0 R3-S2 — a configured neural cross-encoder failed to initialise or errored mid-flight and the runtime fell back. Distinct from "lexical" so clients can detect the silent downgrade in band (previously this was only a tracing::warn! event, which the G8 closure claim overstated as “fail loud”).
• "none" — reranking disabled at this tier.

candidate_counts: CandidateCounts

Candidate-pool sizes coming out of each retrieval stage before fusion. Useful for spotting empty-FTS or empty-HNSW degradations.

blend_weight: f64

Semantic blend weight applied during fusion. 0.0 for keyword_only mode; otherwise the average semantic weight across the returned candidates (varies 0.50→0.15 with content length).

Trait Implementations

impl Clone for RecallMeta

fn clone(&self) -> RecallMeta

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for RecallMeta

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

Formats the value using the given formatter.

impl Serialize for RecallMeta

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

where __S: Serializer,

Serialize this value into the given Serde serializer.