Manifest V3

#How Manifest V3 works

The manifest names the extension's permissions, its background worker, its content scripts and its icons. The background worker is an extension service worker that wakes on events. Network changes, such as blocking or rewriting requests, use declarative rules that the browser applies. Extensions cannot run arbitrary code that a server sends at runtime.

#Why it matters for AI agents

The platform sets what an extension can do. Because the background worker can stop when it is idle, an agent extension must save its state in storage, not in memory. Because remote code is not allowed, a change to the extension's logic needs a new package. Data that the extension reads, such as a list of sites, can change without a new package.

#Wield and Manifest V3

Wield's recipes are data, not code. No JavaScript from the registry runs in the page. This fits the no-remote-code rule of Manifest V3. It is a design fit, not a compliance certification.

Wield's extension is not yet in the Chrome Web Store. Until it is, the extension is installed unpacked from the user's computer.

#Related terms

• Extension service worker
• Content script
• Native messaging
• Chrome DevTools Protocol

#FAQ

#Does Manifest V3 work in Edge and Brave?

Edge and Brave are Chromium-based browsers, and Wield's extension runs in both, along with Chrome, Arc, Vivaldi, Opera and Chromium. Check each browser's own extension documentation for version details.

#What changed from Manifest V2?

Manifest V2 used a persistent background page and allowed remotely hosted code. Manifest V3 replaces the background page with a service worker, uses declarative network rules and bans remotely hosted code.