
Replace the slow, prose model with Jev, a system one decision model that returns typed values and probabilities in milliseconds, delivering fast, cost-efficient, validated decisions.
Design around latency, cost, context, throughput, and modality to optimize Jev deployments, balancing 75–500 ms latency, 4.2 cents per million input tokens, 64k/32k context, and 250k tokens per second.
Apply six gate questions to decide when Jev is the wrong tool for a step, avoiding writing, arithmetic, date comparisons, open-ended answers, and a reasoning trail for an auditor.
Install the TypeSafe SDK in a fresh environment, point it at a live Jev endpoint, and run a single Noul call to measure latency and get a probability.
Jev introduces noul, a probability score from 0 to 1 for propositions, where the number is both the answer and the certainty guiding four steps and per-question thresholds.
Learn to use a one-dimensional score with ordered levels from level zero to level two, describing observable behavior rather than labels, using fractional scores and weighted composites for spectrum reasoning.
Master fast primitive selection by identifying propositions as nouls, exclusive buckets as choices, and ordered positions as scores, while avoiding fake scales, overlapping options, and noul sprawl.
Learn when and how to use json structures to define instructions, options, levels, and criteria, with worked examples and uniform option sets for cleaner model outputs and clearer probabilities.
Demonstrates one call, three primitives—Choice, Score, and Noul—driven by a Python routing rule, with policy thresholds guiding ticket routing and escalation decisions.
Define per-action cost thresholds to govern ai behavior, using three tiers: act, confirm, and human, and set action-specific safety bars based on consequences like read-only, money moves, and irreversible actions.
Pin the exact model version for production, verify on every call, and guard against drift when new versions ship; refuse actions on mismatched models and re-tune thresholds with each update.
Discover speculative fan-out and parallel sampling to speed AI decisions by asking all needed questions in one call, then branch in code for routing and confidence-based decisions.
Decompose a complex judgment into atomic scores for Python experience, leadership, and system design. Normalize and combine them with code-based weights to reveal the composite scoring decision.
Adopt the cascade to route intent swiftly through four tiers—Jev classification, plain code, frontier model, and human—reducing cost and latency while preserving accuracy.
Explore how retrieve-then-judge, fan-out, composite scoring, confidence gating, and cascade form a complete production system, and learn anti-patterns like sequential chaining and cross-type thresholding that hurt latency and explainability.
Jev demonstrates high-volume classification by splitting generation from classification, measuring 1,018 papers for $0.08 with 256 ms latency. Summarisation costs ~ $3.99, illustrating relevance filtering before expensive steps.
Re-score the shortlisted results after vector search by asking a relevance question per candidate and using a Score to boost top-1 accuracy. Over-retrieve to boost recall, then re-rank.
Screening RAG passages re-ranks retrieved text by three questions—relevance, contradiction, and presence of model instructions—reducing padding, cost, and exposure, while enforcing sanitization and layered safeguards.
Apply guardrails for llm input-output by implementing inbound and outbound checks with a severity score, tagging results by family (prompt injection, data leakage, unsafe content), and maintaining a latency budget.
Explore hierarchical classification across large taxonomies and learn how beam search fixes greedy errors by carrying uncertainty across top branches to rank complete paths.
This lab demonstrates screening and re-ranking in a RAG pipeline, reducing token spend and filtering out stale policies and injections to improve accuracy with fewer passages.
Compare sequential, fully concurrent, and capped concurrency using an async client to process twenty tickets, measure latency, respect rate limits with a semaphore, and see identical results.
Log every decision as structured data and query the log to reveal model version, full distribution, confidence, latency, cost, and a traceable id.
Build a gold set you can measure against by sampling real traffic, labeling by hand, over-sampling hard cases, and freezing a 200-row csv or jsonl in version control.
Compare model accuracy with calibration to reveal when predictions mean anything. Understand how to use reliability curves and expected calibration error to detect overconfidence and guide automated decisions.
Identify the nine jaggedness failure modes in fast, typed ai decisions and apply concrete workarounds, from literal reading and maths to dates, indirection, and generation.
Capstone brief: build Fernway's end-to-end support-desk autopilot and report per-ticket cost versus a three-cent baseline. Gate actions by justified thresholds, using deterministic code for routine cases and llm for tail.
This course contains the use of artificial intelligence.
You already have a language model in production, and you are paying for it — four seconds per decision, three cents per call, and a schema-validation failure every now and then that quietly falls back to a human. The routing, the triage, the classification, the moderation, the re-ranking: none of it ever needed prose. It needed a value.
Jev is TypeSafe's first System One model, and it is not a cheaper chat model. You hand it your application state — a string, a JSON object, a conversation — plus typed questions, and it returns typed values with calibrated probabilities in 70 to 500 milliseconds. There is no JSON to parse, because there was never a string. Hallucinated structure isn't unlikely; it's unrepresentable.
This course takes you from that idea to a system you can defend in a design review. You'll learn the three primitives — Choice, Score and Noul — and how to pick between them without hesitating. You'll learn why reading only the winning label throws away most of what the model told you, and how to gate real actions on calibrated confidence with a different bar for every blast radius. You'll work through the five documented production patterns: speculative fan-out, confidence-gated routing, composite scoring, the cascade, and retrieve-then-judge — and how they compose without tangling your control flow.
Then we get practical about running it. Async clients and real concurrency. Rate limits, and the genuinely sneaky way they fail — your latency climbs while your error dashboard stays green. Cost engineering, where trimming state makes the system cheaper and more accurate at the same time. Latency budgeting inside a one-second request. And an honest tour of all nine documented failure modes, because a model that cannot do arithmetic or compare dates is a model you should design around deliberately.
Every section builds on one running example: Fernway, a 410-person SaaS company routing twelve thousand support tickets a month. By the final section you'll have built their triage autopilot end to end — and reported what it costs per ticket against the all-LLM baseline, because being able to state that number is what separates a demo from something a business adopts.
Jev entered early access on 21 September 2026. Every technical claim here is sourced from the live documentation, and the course tells you exactly which numbers to re-verify as the model moves.