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	9520
title	LivePreview: Propagate active theme to popout child window
state	Closed
labels	bugai
assignees	tobiu
createdAt	Mar 19, 2026, 5:47 PM
updatedAt	Mar 19, 2026, 5:50 PM
githubUrl	https://github.com/neomjs/neo/issues/9520
author	tobiu
commentsCount	1
parentIssue	null
subIssues	[]
subIssuesCompleted	0
subIssuesTotal	0
blockedBy	[]
blocking	[]
closedAt	Mar 19, 2026, 5:50 PM

LivePreview: Propagate active theme to popout child window

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

Closed v12.1.0 bugai

tobiu commented on Mar 19, 2026, 5:47 PM

When popping out a LivePreview from a markdown tutorial inside the Portal app, the theme of the popup window does not reliably reflect the current theme of the Portal app (e.g. falling back to light theme even if the Portal uses dark theme).

This happens because:

apps/portal/childapps/preview/neo-config.json is missing the neo-theme-neo-dark and neo-theme-light options, causing it to fall back to defaults when one of these is requested.
In src/code/LivePreview.mjs -> onWindowConnect(), the active theme is not explicitly passed to the mainView of the new window. Because the previewView itself already has the theme property internally set from its original creation context, applying the theme to previewView directly causes a no-op in the reactivity system, meaning the class is never added to the new DOM. Setting it on the window's mainView (the Viewport) resolves this cleanly and naturally cascades variables down.

This ticket aims to:

Update apps/portal/childapps/preview/neo-config.json to mirror the Portal app's themes array.
Update src/code/LivePreview.mjs to apply the current theme to the new mainView during onWindowConnect().

tobiu added the bug label on Mar 19, 2026, 5:47 PM

tobiu added the ai label on Mar 19, 2026, 5:47 PM

tobiu referenced in commit f492172 - "fix: LivePreview popout window theme propagation (#9520)" on Mar 19, 2026, 5:49 PM

tobiu Mar 19, 2026, 5:49 PM

Input from Gemini 3.1 Pro:

✦ The LivePreview popout window theme propagation issue has been fully resolved.

The core problem was twofold:

The child app (apps/portal/childapps/preview/neo-config.json) was missing the new neo-theme-neo-dark and neo-theme-light options in its themes array, causing it to fall back incorrectly.

In src/code/LivePreview.mjs -> onWindowConnect(), the active theme was not being properly cascaded to the new window. Because the previewView component already had its theme property internally set from its original creation context, applying the theme directly to it again caused a no-op in the config reactivity system (skipping afterSetTheme), meaning the class was never added to the new DOM root.

The solution ensures the neo-config.json themes are fully synchronized with the Portal app. Architecturally, the correct fix was applied by setting the active theme on the mainView (the Viewport) of the new popup window instead. The Viewport natively handles setting the root theme, which cascades correctly to previewView and all dynamically executed components (like the FormContainer).

All changes have been successfully committed and pushed to the dev branch.

tobiu assigned to @tobiu on Mar 19, 2026, 5:50 PM

tobiu closed this issue on Mar 19, 2026, 5:50 PM