Skip to content

This is one of the two tracks of the next series. The other is LEB Security.

AI Benchmark · LEB · next series

LEB Default proposed

One of the two tracks of the next LEB series: the everyday maintenance of a working system. The agent works on a system with maintenance flaws planted in it, and nothing in the task asks for security work. How LEB works today, and how its levels differ, is on the Benchmark page.

Read the design

There are no results yet. This page says where the series stands and what will appear here. Nothing on it is a score.

What this track measures

Architecture, bugs, performance, code quality and compatibility. No vulnerability is planted, and the task asks for no security work.

The code it starts from is described as "no known vulnerabilities within the reviewed scope", never as free of them.

The Default and Security scores of a configuration are shown side by side and never added.

Where the series stands

The next series is a proposal: its design was decided on 12 October 2026, and its normative texts (the spec, the protocol, the scoring and the levels) are written after a pilot has validated the process. It changes nothing in LEB-100 or LEB-300, whose results stay as published. There is no scoreboard yet.

The reference systems

Each track is measured on several reference systems, and each system yields both tracks: two planting profiles of the same clean code. The same letter is the same system. The pilot will have 3 systems; the evaluation set, about 6.

System Domain Stack Instance Status
A Condominium management (CondoDesk) Java 21 · Maven · PostgreSQL LEB-D-300-A In authoring

How a case runs

A case is one system, one track and one agent configuration.

  • 5 runs per case, and all of them count.
  • The requested model is pinned in the client, in the main conversation and in every subagent, so that no substitute can answer.
  • An automated lab runs each case, from the restoration of the machine to the filing of the evidence.

What will be published

For each configuration and track:

  • the quality of the evaluable deliveries, with its uncertainty interval;
  • the completion rate with the requested model;
  • the expected score per scheduled attempt;
  • blocks (at the start and during the work), model switches, exhausted budgets and lab failures, each counted separately.

The answer key

The answer key of an instance is published on GitHub with the instance, before its first run, and the machines that run the agents cannot reach GitHub. Each run also records the model's training cutoff, for what a model may have seen in training.

Comparison

A score of the next series is never set beside one of LEB-100 or LEB-300.

Read more