Usable Browser Agent (free) Firefox

Usable Browser Agent (free)

By: STS Ky Add-on
Lets a local AI agent (Claude Code or Codex) drive this Firefox browser through a local MCP server, using your real logged-in sessions. Nothing leaves your machine. Free for personal use and evaluation.

Features & Capabilities

Usable Browser Agent lets your AI agent act in your real Firefox browser, not a throwaway profile. You log in once and the agent works on real sites as you.

<strong>Free tier</strong>

This is the free personal/evaluation tier: the same single-session extension as the commercial build, licensed for personal, non-commercial use and for evaluating the product before buying. Commercial use (in or for a business, in paid client work, or inside a commercial product or service) requires the commercial license, a one-time $39 purchase at <a href="https://prod.outgoing.prod.webservices.mozgcp.net/v1/9ed6e7b99955a60a7edca65618ab32c4bf0f4caea877516a7575abd5ba5ff8bb/https%3A//savvytechsphere.com/usable-browser-agent" rel="nofollow">savvytechsphere.com/usable-browser-agent</a>. There is no license key in the product and nothing checks for one; the tiers differ only in the license grant and the add-on identity.

<strong>How it works</strong>

The extension is one half of the product. The other half is a small MCP server that runs on your own machine. Your agent (Claude Code, Codex, or any MCP client) talks to that server, and the server relays commands to this extension over a WebSocket on 127.0.0.1. Nothing leaves your machine. Without the local server the extension does nothing; the toolbar popup shows whether it is connected. Get the free server (with a one-command installer and docs) from the public repository: https://github.com/Savvy-Tech-Sphere/usable-browser-agent-free (clone it, or download the zip from its Releases page), then run node bin/uba-install.mjs to register it with Claude Code or Codex.

<strong>What the agent can do</strong> <ul><li>Read pages as an accessibility-style snapshot with stable element refs</li><li>Click, type, select, scroll, hover, drag, and fill forms</li><li>Navigate, manage tabs, take screenshots, save the page as a PDF, and download files</li><li>Read and write the clipboard, watch network activity, and handle dialogs</li></ul> <strong>Credential safety, each point backed by an automated test</strong> <ul><li>You store credentials in a local vault file. The agent logs you in by alias and never receives the credential value.</li><li>Credentials are refused on hosts the alias does not allow, so a lookalike domain cannot phish a stored login.</li><li>Secret values are scrubbed from every tool result the agent reads, and screenshots are blocked while a credential is visible on the page.</li></ul> <strong>Privacy</strong>

The extension collects no data. There is no analytics, telemetry, or remote logging, and it executes no remotely hosted code. It talks only to the server process on your own machine over 127.0.0.1. Page content, screenshots, and clipboard data go only to the agent you run locally. Nothing is sent to Savvy Tech Sphere.

<strong>Setup</strong>

Setup takes a few minutes: install this extension, run the local MCP server, and point your agent at it. The server and the setup instructions are provided from the product page: <a href="https://prod.outgoing.prod.webservices.mozgcp.net/v1/9ed6e7b99955a60a7edca65618ab32c4bf0f4caea877516a7575abd5ba5ff8bb/https%3A//savvytechsphere.com/usable-browser-agent" rel="nofollow">savvytechsphere.com/usable-browser-agent</a>. Requires Firefox 142 or later.

<strong>Known limits</strong>

The agent acts on the currently active tab, so keep the tab you want it to use focused. The eval tool runs in the page context, so pages with a strict Content Security Policy can block it.

User Growth & Download Statistics

Manifest V2 Add-on
By:
STS Ky
Daily users:
1
Version:
0.7.0 Last updated: 2026-09-05
Version code:
6457625
Creation date:
2026-09-02
Firefox add-on GUID:
usable-browser-agent-free@local
Firefox add-on numeric ID:
3065197
Weekly download count:
4
Firefox on Android:
No
Risk:
Very high risk impact High risk likelihood
Permissions:
Content scripts matches:
  • <all_urls>
Size:
40.79KB
URLs:
Website ,Privacy policy
Full description:
See detailed description
Source:
Firefox Add-ons Store
Data ingested on:
2026-09-26
Compare stats and ranking:

Contact the developer

Chrome-Stats does not own this Firefox add-on. Please use these information below to contact the Firefox add-on developer.
Developed by:
STS Ky
Firefox Add-ons Store
https://addons.mozilla.org/firefox/addon/usable-browser-agent-free/
Website:
https://savvytechsphere.com/#contact

Is Usable Browser Agent (free) Safe?

Risk impact
Risk impact measures the level of extra permissions an extension has access to. A low risk impact extension cannot do much harms, whereas a high risk impact extension can do a lot of damage like stealing your password, bypassing your security settings, and accessing your personal data. High risk impact extensions are not necessarily malicious. However, if they do turn malicious, they can be very harmful.

Usable Browser Agent (free) requires a lot of sensitive permissions. Exercise caution before installing.

Risk impact analysis details
  • Critical Grants access to browser tabs, which can be used to track user browsing habits and history, presenting a privacy concern.
  • Critical ****** ****** ** *** ********* ****** * *********** ******** **** ** ** *** ******* *** ****** **** **** *** ******* *****
  • High ****** *** ********* ** ******* *** ******* ******* ** ****** *** *** ******** ******
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  • Medium ****** ********** ** ******** ********** *** ********* ******* ******** ****** ******** ****** ********
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Risk likelihood
Risk likelihood measures the probability that a Firefox add-on may turn malicious. This is determined by the publisher and the Firefox add-on reputation on Firefox Add-ons Store, the amount of time the Firefox add-on has been around, and other signals about the Firefox add-on. Our algorithms are not perfect, and are subject to change as we discover new ways to detect malicious extensions. We recommend that you always exercise caution when installing a Firefox add-on.

Usable Browser Agent (free) is recently added, and hasn't been around long enough for us to gather enough data to accurately assess its risk level.

Risk likelihood analysis details
  • High This extension was recently updated in the past month. New updates may not be stable or safe.
  • High **** ********* *** ******** ****** *** ********** *** *** ** ****** ** *****
  • High **** ********* *** *** **** ****** ********* ********** *** *** ** ****** ** *****
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