What is the 'Neural Link'?

The Neural Link is a bi-directional bridge that connects AI agents (like Gemini or Claude) directly to the Neo.mjs runtime. It allows agents to 'see' the application's Scene Graph, inspect component state, verify event listeners, and even mutate the running application in real-time. This turns the application into a 'glass box' for AI, enabling autonomous debugging and feature development.

Why is Neo.mjs called an 'Application Engine' instead of a framework?

Traditional frameworks are general-purpose libraries (like a Toyota) that help you organize code, but they compile away into ephemeral DOM nodes. Neo.mjs is a precision-engineered runtime (like an F1 car), similar to Unreal Engine for games. It maintains a persistent 'Scene Graph' of objects in a separate worker thread. These objects retain their identity, state, and relationships, allowing for advanced capabilities like multi-window orchestration, runtime permutation, and deep AI introspection that are impossible with 'melted plastic' DOM-based frameworks.

What is 'Context Engineering'?

Context Engineering is the practice of curating the environment and information flow for AI agents to maximize their autonomy. In Neo.mjs, this is implemented via three Model Context Protocol (MCP) servers: a Knowledge Base for semantic code understanding, a Memory Core for learning from past sessions, and a GitHub Workflow server for project management. This ecosystem allows agents to work as fully integrated members of the development team.

What is 'Object Permanence' in the context of Neo.mjs?

In Neo.mjs, UI components are persistent JavaScript objects living in the App Worker, not just transient rendering results. This 'Object Permanence' means a component (like a Dashboard) maintains its state (scroll position, user input, internal logic) even if it is detached from the DOM or moved to a different browser window. This is the 'Lego Technic' approach versus the 'Duplo' approach of traditional frameworks.

What is an 'Agent Operating System'?

Neo.mjs v11 introduced the concept of an Agent OS, where the platform itself provides the tools and interfaces for AI agents to operate. It combines a standalone, type-safe AI SDK for autonomous 'Code Execution' with the Neural Link for runtime control. This enables agents to monitor, debug, and heal the application autonomously, effectively acting as an operating system for synthetic intelligence.

How does Neo.mjs handle multi-window applications?

Neo.mjs uses shared web workers to run a single application instance across multiple browser windows. All windows share the same application state and data in real-time. Components can even move between windows while retaining their JavaScript instances. This enables desktop-class experiences like multi-window IDEs, browser-based email clients, and multi-screen control rooms.

What makes Neo.mjs different from React, Angular, or Vue?

Neo.mjs is fundamentally different in its architecture: (1) It uses True Multithreading via web workers to prevent UI jank, (2) It is an AI-Native Application Engine with built-in bridges for AI collaboration, and (3) It treats components as persistent objects in a Scene Graph, enabling native multi-window support and runtime permutation.

Frontmatter

id	8877
title	Replace Siesta Guide with Playwright Testing Guide
state	Closed
labels	documentationai
assignees	tobiu
createdAt	Jan 25, 2026, 11:33 AM
updatedAt	Jan 25, 2026, 12:19 PM
githubUrl	https://github.com/neomjs/neo/issues/8877
author	tobiu
commentsCount	1
parentIssue	null
subIssues	[]
subIssuesCompleted	0
subIssuesTotal	0
blockedBy	[]
blocking	[]
closedAt	Jan 25, 2026, 12:19 PM

Replace Siesta Guide with Playwright Testing Guide

Name: Neo.mjs Application Engine
Author: Neo.mjs

Closed v11.24.0 documentationai

tobiu commented on Jan 25, 2026, 11:33 AM

The goal of this task is to update the testing documentation to reflect the migration from Siesta to Playwright.

Tasks:

Remove the obsolete guide learn/guides/testing/UnitTestingWithSiesta.md.
Create a new guide learn/guides/testing/Playwright.md.
Update learn/tree.json to replace the Siesta guide entry with the new Playwright guide.

New Guide Content:

Why Playwright?: Explain the shift (speed, single-thread unit testing, active development, agent-friendly).
Running Tests: Document the available scripts:
- npm run test
- npm run test-unit
- npm run test-components
Unit Test Structure: Explain the single-thread environment, setup.mjs, and direct imports.
Examples: Provide code snippets showing setup(), Neo.create(), and VDOM assertions based on existing tests (e.g., button/Base.spec.mjs).
Configuration: Mention test/playwright/playwright.config.*.mjs files.

Context: The migration to Playwright is complete, and the Siesta guide is now misleading. This update ensures the documentation matches the current repository state.

tobiu added the documentation label on Jan 25, 2026, 11:33 AM

tobiu added the ai label on Jan 25, 2026, 11:33 AM

tobiu referenced in commit 56b5aaa - "docs: Replace Siesta guide with Playwright testing guide (#8877)" on Jan 25, 2026, 12:18 PM

tobiu Jan 25, 2026, 12:18 PM

Input from Gemini 3 Pro:

✦ I have completed the migration of the testing documentation from Siesta to Playwright and finalized the new guide.

Changes:

Deleted: learn/guides/testing/UnitTestingWithSiesta.md

Created: learn/guides/testing/Playwright.md

Why Playwright: Explains the shift to a modern, fast, and agent-friendly framework.

Unit Testing Architecture: Details the unique single-thread Node.js simulation for App/VDom/Data workers.

Critical Imports: Documents the mandatory core/_export.mjs augmentation and VdomHelper/DomApiVnodeCreator requirements.

Namespace Isolation: Explains the setupClass guardrails and the requirement for unique class names in the persistent worker environment.

Test Lifecycle: Provides patterns for test.beforeEach and test.afterEach to prevent memory leaks and ID collisions.

Common Patterns: Includes examples for testing Logic/State, Async/Lifecycle, Reactivity/Effects, and Complex VDOM Logic.

Updated: learn/tree.json to replace the Siesta entry with the new Playwright guide.

The new guide is comprehensive and accurately reflects the current state of the Neo.mjs Application Engine test suite.

tobiu assigned to @tobiu on Jan 25, 2026, 12:19 PM

tobiu closed this issue on Jan 25, 2026, 12:19 PM