Gives Gemini CLI a hosted browser to test your running app and leave before/after proof of each UI change for reviewers.
by Fullstory· Web & browserUnclaimed · Yours? Claim it
4 images
About
Subtext Verify is the companion to Fullstory's Subtext. It lets your agent open a cloud-hosted browser against your running app, prove a UI change with before/after screenshots and network traces, and leave the evidence where reviewers will see it: in proof documents, viewer links and comments. As a Gemini CLI extension it adds Verify's skills and the Subtext tunnel, a local MCP server that lets the hosted browser reach your localhost dev server. What you can do with it - Connect a hosted Chromium browser to your app, or to a local dev server through the tunnel, and share a trace link you can watch live and replay later - Click, fill, hover, drag, upload files and press keys, and wait for the page to settle - Take component-tree snapshots and screenshots, inspect network requests and console messages, and emulate devices - Capture before/after evidence of a UI change in a proof document, with screenshots, diffs and logs, then close it as a permanent record - Leave comments on a page for your team, and read, reply to and resolve their feedback - Start a .sightmap/ of your components, so the next agent understands the UI without reading the source How it connects Install Subtext first: its hosted subtext MCP server serves Verify's live-browser, proof document and comment tools. Then install this extension with gemini extensions install https://github.com/fullstorydev/subtext-verify. It adds the subtext-tunnel server (npx -y @subtextdev/subtext-cli@latest tunnel mcp), which the hosted browser needs only to reach localhost. Good to know - Verify is in closed beta: its tools appear only when your Subtext org has the verification flag turned on. You can join the waitlist at subtext.fullstory.com. - Reviewing recorded sessions and managing privacy rules live in Subtext itself, not here. - Uploading a project's .sightmap/ for richer snapshots needs Python 3.9 or later and PyYAML. - Close the hosted browser when you're done: open connections count against your quota.
Once it’s added
“Prove a small UI change on my local dev server.”
Before you add it
Reads only
Your running app in a hosted browser: component snapshots and screenshots · Network requests and console messages from each page · Comments your team left on a page
Makes changes · your agent can ask first
Clicks, types and navigates in the hosted browser · Creates proof documents with screenshots, diffs and logs · Adds, replies to and resolves comments · Writes .sightmap/ files in your project
From people who use it
Step by step
Nothing new reaches your agent until a person has looked at it.
Plugins people install alongside Subtext Verify.
No reviews yet. Used Subtext Verify? Say how it went.
Write a reviewRuns on your machine.
gemini extensions install https://github.com/fullstorydev/subtext-verify
Scanned and passed · checked 6 h ago
Plugins people install alongside Subtext Verify.
Hand web tasks to a Browser Use agent in a cloud browser: it browses sites, fills in forms and pulls out the data you asked for.
ByteDance's local MCP server that lets your agent drive a real browser: open pages, click, fill in forms, read pages and take screenshots.
Microsoft's MCP server for browser automation with Playwright: your agent navigates, clicks and fills in pages from structured snapshots.
Plans and builds scraping pipelines with Firecrawl or local Python, and won't hand over the data until it passes a validation check.
Nobody has shared how they use Subtext Verify yet.
“Fix the misaligned header and capture before/after proof.”
“Open the checkout page on staging and screenshot it on a mobile device.”
“Explore the signup flow and leave comments on anything that looks off.”
“Submit this form and show me the network requests and console errors.”
“Read the team's comments on this page and resolve the ones you've fixed.”
Scanned on every change, and again when our rules improve.
Tell us and a person on the trust team will look at it. Or email [email protected].
Security scan
Passed
Safe to install in every agent it supports. Extensions.
