Exnos

Live browser-state verification for AI coding agents.

Your AI says "done." Exnos is how it knows.

One tool call returns the full state of the Chrome tab you're looking at: every field, every button, every console error, network requests, storage, performance—in milliseconds. Read-only. Local. Free to use. Built by GOL Productions.

By GOL Productions.

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The Problem

AI coding agents edit files and hope for the best. When something breaks:

You: "The button doesn't work"
AI:  "Can you check the console for errors?"
You: "It says TypeError something something"
AI:  "Can you paste the full error?"

Back and forth. Slow. Frustrating.

The Solution

You: "The button doesn't work"
AI:  [calls exnos_verify]
AI:  "Console shows 'TypeError: handleClick is not defined' at line 47.
      The handler was renamed to onClick. Fixing now."

Exnos gives your AI eyes. It sees what you see—instantly.

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Install

npx @golproductions/exnos@latest setup

That's it. Detects Claude Code, Cursor, and Windsurf—registers with all of them, opens the extension folder, tells you to load it in Chrome. Takes 30 seconds.

1. Connect your agent

{ "mcpServers": { "exnos": { "command": "npx", "args": ["@golproductions/exnos"] } } }

Or for Claude Code:

claude mcp add --scope user exnos -- npx @golproductions/exnos

2. Load the extension

npx @golproductions/exnos@latest path

Open chrome://extensions → Developer mode → Load unpacked → select that folder.

Badge reads ON when connected.

Updating

npx fetches the newest server on its own; the Chrome extension does not update itself. After an update, open chrome://extensions and click reload on Exnos. If it still shows the old version, remove it and load the folder printed by npx @golproductions/exnos@latest path.

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What Exnos Can Read

• Local pages, always: localhost, 127.0.0.1, *.localhost, and local files.
• Any other site, only if you allow it: open the site and click the Exnos icon in Chrome's toolbar. Click again to remove it. Your AI cannot allow a site.
• Tabs on other sites are not listed, matched or described to your AI.
• The console and network capture runs only on sites Exnos can read. A page that was already open when you allowed its site needs one reload before its console and network are captured.

What It Sees

Category	Data
Identity	URL, title, ready state
Page text	The page's rendered text, first 3,000 characters (maxText up to 20,000), marked when cut
Forms	Every field in view with its live value and a selector (passwords, API keys, tokens, CSRF tokens, card numbers and seed phrases masked)
Buttons	Text, disabled state and a selector
Checkboxes	Checked state with labels
Alerts	Visible error/success/warning UI
Console	Errors (with message and stack), warnings, and failed resource loads since page load, counted separately
Network	This site's fetch/XHR: URL, status, short response body; the last 30 failed and 20 successful. Other sites' requests only on request.
WebSocket	The last 30 sent and received frames
Performance	Page load, TTFB, paint timing
Focus	Which element has focus
Shadow DOM	Pierces web component boundaries
Iframes	Same-origin content + cross-origin count
Screenshot	Optional PNG, returned as an image

Only when asked: localStorage, sessionStorage and cookies (includeStorage, with tokens, keys and session values redacted), requests to other sites (thirdParty), and window.__* app state (appGlobals).

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Tools

Tool	Purpose
exnos_verify	Full live state. The main tool.
exnos_tabs	List the tabs Exnos can read.
exnos_screenshot	PNG screenshot of visible tab.
exnos_fetch_tabs	Verify multiple tabs at once.
exnos_record_start	Record a tab over time: saves what changed every few seconds.
exnos_record_status	List recordings, including ones from earlier sessions.
exnos_record_read	Read back a recording: a time range, latest or earliest first.
exnos_record_stop	Stop one recording, or all of them.

exnos_verify parameters

Parameter	Description
tab	Match tab by URL or title substring. Default: active tab.
selector	CSS selector for deep-dive: text, bounds, computed styles, HTML.
maxText	Characters of page text, and of selector text and HTML. Default 3,000 / 2,000, maximum 20,000.
includeHidden	Also list fields, buttons and checkboxes outside the viewport or hidden, including type=hidden inputs. Default: false. Page text always covers the whole page; text hidden with display:none is never included.
thirdParty	Include requests to other sites. Default: false.
includeStorage	Include storage and cookies, credentials redacted. Default: false.
appGlobals	Include window.__* app state. Default: false.
screenshot	Also capture a PNG of the visible tab, returned as an image.

Selector deep-dive

Pass selector to get the following for the first match. If nothing matches, selectorFound is false and the rest of the state (errors included) still comes back.

• selectorText — inner text content
• selectorVisible — actually visible?
• selectorBounds — {top, left, width, height}
• selectorHTML — outer HTML
• selectorStyles — computed: color, backgroundColor, fontSize, fontWeight, fontFamily, padding, margin, border, zIndex, overflow, transform, transition

Record mode

exnos_verify is a snapshot. A recording keeps watching: every few seconds Exnos samples the tab and saves what changed, so a bug that comes and goes, or a list that changes all day, can be read back later.

AI:  [calls exnos_record_start { tab: "localhost:3000", selector: "#orders", items: "tr", every: 2, duration: 120 }]
     ... two hours later, from any session ...
AI:  [calls exnos_record_read { lastMinutes: 15 }]

Each saved sample holds the URL, title, whether the tab was visible, and what is new since the last sample: console errors and warnings, failed resource loads, this site's requests and failed requests to other sites. With a selector it also holds the text of that part of the page and its items ([text, link, top, left, visible]). Unchanged samples are not saved; a heartbeat every 30 seconds shows the recording went on.

Parameter	Description
tab	Match tab by URL or title substring. Default: active tab. Fixed when recording starts.
selector	Part of the page to watch: up to 20 matching elements, each with up to 1,000 characters of text and 100 items. Without it: URL, title, visibility, errors and requests only.
items	Repeated items inside the selector (rows, cards). Default: links.
every	Seconds between samples. Default 2, minimum 1.
duration	Minutes to record. Default 60, maximum 1440 (24 h).
includeHidden	Also save items scrolled out of view. Default: false.
maxMB	Stop at this file size. Default 200.
name	Short label added to the recording id.

exnos_record_read parameters:

Parameter	Description
id	Recording id. Default: the newest recording.
lastMinutes	Only samples from the last N minutes.
from / to	Only samples inside this time range (ISO time).
limit	How many samples to return. Default 10, maximum 200.
oldestFirst	Earliest matching samples instead of the latest. Default: false.
changesOnly	Skip heartbeat lines. Default: true.
full	Untrimmed text and items. Default: false (300 characters, 40 items per region).

• Recordings are saved on this machine in ~/.exnos/recordings/ (<id>.jsonl, one line per saved sample). The AI cannot choose the file path.
• A recording keeps running after the AI session ends, until its duration is up, the tab closes, it reaches maxMB, or exnos_record_stop is called. A later session can list, read and stop it. Up to 3 recordings run at a time per session.
• Chrome must stay open. A sample that fails (Chrome closed, page loading) is saved as an error line, at most one every 30 seconds.
• The same scope as exnos_verify, checked on every sample: if the tab moves to a site Exnos may not read, the recording stops. Form field values are never recorded, but text typed into editable parts of the page can appear in the watched text. URL parameters with sensitive-looking names are masked.
• Chrome slows hidden tabs. For pages that update live, keep the recorded tab visible.

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CLI

npx @golproductions/exnos@latest setup       # configure everything
npx @golproductions/exnos@latest uninstall   # remove everything Exnos added (run it in each project where you ran init)
npx @golproductions/exnos@latest path        # extension folder path
npx @golproductions/exnos@latest init        # write rules to agent config
npx @golproductions/exnos@latest rules       # print rule text

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Architecture

┌─────────────┐     MCP/stdio      ┌─────────────┐    WebSocket     ┌─────────────┐
│  AI Agent   │ ◄────────────────► │ MCP Server  │ ◄──────────────► │  Extension  │
│             │                    │ :17872      │                  │             │
└─────────────┘                    └─────────────┘                  └──────┬──────┘
                                                                           │
                                                                    Chrome APIs
                                                                           │
                                                                    ┌──────▼──────┐
                                                                    │   Your Tab  │
                                                                    └─────────────┘

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Smart Features

• State change detection: Reports changed: true/false on repeated calls, over the whole page text, form values, button and checkbox states, alerts and error counts
• Proxy mode: Multiple agents share one extension connection; when the connected one closes, another takes over
• Auto-reconnect: Extension reconnects after Chrome/server restart
• Failures first: Network errors surface before successful requests
• Cross-origin awareness: Reports iframe count even when content isn't readable
• Out of the page's reach: what Exnos captures is kept where the page's own scripts cannot read or change it
• Untrusted content label: replies tell the AI that page text is data, not instructions

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Privacy

Exnos sends nothing to GOL Productions. No account, no telemetry, and no GOL server. Traffic goes from the extension to a local server on 127.0.0.1, which only accepts the Exnos extension and requests from this machine: a web page cannot connect to it.

However: what Exnos returns goes to your AI agent, which forwards it to its model provider. That is why Exnos reads only local pages and the sites you allow, masks passwords and similar fields, and returns storage and cookies only when asked, with credentials redacted. Redaction works by pattern, so it can miss a secret in an unusual place.

Recordings are saved only on this machine, in ~/.exnos/recordings/; they reach the AI only when it reads them back. Delete the folder to delete them.

Allow the sites you are debugging, not your banking tab.

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Notes

• Server: 127.0.0.1:17872. The Chrome extension always connects on this port, so keep it free.
• GET / returns {"exnos":true,"extension":true|false}
• Console/network capture starts when a page loads on a site Exnos can read; pages already open need one reload
• Internal pages (chrome://) cannot be inspected

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License

Free to use, personal or commercial, under the GOL Free License. Exnos is built by GOL Productions: you may use it and share unmodified copies with the credit, but not publish changed versions, build your own product from it, or sell it. What you make with it is yours. See LICENSE.

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GOL Productions

Exnos is part of the GOL Productions toolchain.

• Check — Anti-hallucination layer for Claude Code
• Envie — AI video rendering with verification

Product page · GitHub