K² model stack

Four models. One shared definition of relevance.

Dense clustering maps semantic neighborhoods, sparse signals capture exactness, fusion blends those signals per query, and reranking enforces calibrated evidence quality. Because all four models tune together on common signals, they form a shared relevance view.

Training loop

Hard negatives keep every model honest

Representative domain queries and mined retrieval errors tune dense, sparse, fusion, and reranker models in one shared optimization cycle.

  • Hard negatives come from evaluation sets and observed failure modes.
  • Each encoder learns the same definition of relevance in shared batches.
Evaluation

One dashboard for the whole stack

Recall, precision, latency, and cost land in a unified harness so teams can tune trade-offs together instead of guessing.

  • Dense, sparse, fusion, and reranker metrics sit side by side.
  • Budget-aware evaluation runs gate releases and surface drift.
Deployment

Open-weight playbooks for your infra

Ship the stack into your VPC or cloud with documented recipes, integration guides, and observability hooks.

  • Reference architectures for vector and sparse stores.
  • Ops runbooks cover rollout, monitoring, and fast rollback.

Retrieval stack in motion

QueryRetrievalFusionRerankerGenerator

Parallel dense and sparse retrievers feed a learned fusion model that shifts between semantic breadth and lexical precision. The reranker then delivers the evidence decision and logs outcomes into the next training cycle.

Stronger retrieval recall

Aligned dense, sparse, fusion, and reranker models can improve on fixed heuristics, with gains measured on domain evaluation sets.

Lower token pressure

Calibration and tighter ranking reduce prompt growth while preserving the evidence quality needed to answer.

Telemetry-grounded decisions

Shared dashboards let you monitor recall, precision, and latency trade-offs in one place.

The result is a retrieval stack tuned to your domain and measured against the same evaluation criteria on every release.

How the retrieval stack compounds

Shared training loops keep dense, sparse, fusion, and reranker models pushing in the same direction.

Dense + sparse stay in sync

Dense clustering maps semantic neighborhoods while sparse tokens capture exact salience.

Fusion ranks by what matters

The learned fusion model dynamically blends the two, producing a ranked shortlist tailored to each query.

Rerankers sharpen the final order

Calibrated scores support thresholds for grounded answers or deferrals.