# Why GraphRAG needs a different decision layer
# System 1 versus System 2 for AI tasks
Daniel Kahneman's cognitive split into System 1 (fast, associative) and System 2 (slow, deliberative) maps to engineering choices for GraphRAG. High-frequency, routine micro-decisions resemble classification or scoring problems and fit a System 1 approach. Autoregressive LLMs are System 2 engines built for token-by-token generation, complex reasoning, and synthesis. Forcing them into high-volume decision roles creates inefficiency.
TypeSafe Jev is described as a System 1 decision model designed to close this architectural gap. It rejects the next-token objective and instead outputs calibrated probability distributions over typed schema options in parallel. That design reduces generation latency and avoids producing conversational prose for what should be structured decisions.
# Jev primitives and how they map to graph tasks
Jev uses schema-first primitives that replace prompt engineering with explicit declarations of the expected output type. The three core primitives are:
- Noul (calibrated Boolean): returns P(Y=1 | X) in [0,1], intended as a well-calibrated probability for binary assertions such as whether two mentions refer to the same entity.
- Score (ordinal rating): returns an ordinal score over a defined scale, which can rank relevance inside retrieved neighborhoods.
Mapping graph micro-decisions to these primitives centralizes deterministic schema handling and generates reliably typed outputs instead of free-form text.
# Operational benefits in GraphRAG pipelines
Using a System 1 decision engine like Jev alongside System 2 LLMs changes where effort and cost are expended:
- Ingestion and maintenance: Jev performs high-frequency identity resolution and predicate normalization with calibrated outputs, reducing repeated LLM calls.
- Retrieval and filtering: Jev ranks and prunes large multi-hop neighborhoods so LLMs receive small, high-relevance contexts for reasoning.
- Latency and cost: Parallel, non-autoregressive decisions run with sub-500ms latency and at lower cost than invoking autoregressive LLMs for every micro-decision.
# How to integrate this pattern
Declare typed schemas for each micro-decision in the pipeline and route those calls to a calibrated decision model. Keep autoregressive LLMs for tasks that need open-ended generation, synthesis, or chain-of-thought reasoning. Reserve the System 1 engine for high-frequency, repetitive tasks that expect structured outputs.
# Bottom line
GraphRAG gains—the relational context and multi-hop reasoning—create a scale problem of many small probabilistic choices. Separating responsibilities so a calibrated, parallel System 1 model handles those choices while LLMs handle reasoning reduces cost, latency, and engineering fragility. Jev's primitives (noul, choice, score) provide a concrete schema-driven way to operationalize that separation.