---
date: "2026-04-15"
title: "Guide V3 Launch — +15 New, 15 Total"
---

# 2026-04-15 — +15 New · 15 Total

## Getting Started (+3 new, 3 total)

- [What is a Harness?](/guide/what-is-harness)
- [Your First Harness](/guide/your-first-harness)
- [Harness vs. Framework](/guide/harness-vs-framework)

## Core Concepts (+4 new, 4 total)

- [Agentic Loop](/guide/agentic-loop)
- [Tool System](/guide/tool-system)
- [Memory & Context](/guide/memory-and-context)
- [Guardrails](/guide/guardrails)

## Practice (+5 new, 5 total)

- [Context Engineering](/guide/context-engineering)
- [Sandbox](/guide/sandbox)
- [Skill System](/guide/skill-system)
- [Sub-Agent](/guide/sub-agent)
- [Error Handling](/guide/error-handling)

## Reference (+2 new, 2 total)

- [Implementation Comparison](/guide/comparison)
- [Glossary](/guide/glossary)

## Showcase (+1 new, 1 total)

- [Shipping Our Windows Client](/guide/nexu-windows-packaging)