Version 1.3.0 · 97 tools · no servers
DevTools you can talk to,
and an agent runway you can trust.
Inspect and copy CSS from any element. Capture full-page screenshots that handle sticky headers and lazy loading. Read Markdown as a document. Then hand the wheel to Claude Code/Desktop, Cursor, VS Code, Windsurf, Antigravity, IntelliJ, Codex, Grok Build, Kimi Code/Desktop, JCode, Cline, OpenCode, Continue.dev, KiloCode, Roo Code, Aider, OpenClaw, Hermes, OpenFang or any other MCP client — driving the browser you are already signed into, with a human able to see and stop what it does.
Chrome, Brave, Edge, Opera and Chromium use the same store package. Firefox is partly supported — see what differs.
Free tier is genuinely useful forever. Pro is $29.99 once, three activations, no subscription.
Why this exists
The automation layer is not the moat
Chrome DevTools MCP, Playwright MCP, mcp-chrome and Browser Use are free, well funded and good. We are not going to out-free Google and Microsoft, and we do not pretend to.
The moat is the human loop
Free tools hand a language model a firehose and hope. T3rnel puts a valve on it: credentials redacted before they reach the model, actions that change pages stop and ask, and a timeline you can scrub backwards when a run goes wrong.
Your real browser, your real sessions
No separate automation browser, no re-authenticating, no automation flags. The agent works in the profile you are already logged into — which is the honest version of the capability other tools chase with fingerprint spoofing.
What you get
CSS inspection
Hover any element and get its real, clean, copyable CSS — with the units the author actually wrote.
Full-page screenshots
One click, the whole page, stitched — and it handles the real web rather than the ideal one.
Markdown viewer
Read .md files as documents, including the ones your agent just wrote.
Page audit and link checking
Accessibility, spelling and links — reported honestly, including what could not be checked.
Record, replay and code export
Click through a flow once. Get a maintainable test that runs in your CI without this extension.
Agent safety
The part that justifies the price: a valve between a language model and your logged-in browser.
Encrypted identity vault
Per-site credentials, encrypted on your device, never written in the clear.
Color picker
Sample and compare colors from any pixel on the page, with palette export.
Clear cache and hard reload
Clear the cache for the current origin and hard-reload the page without digging through DevTools.
React debugging
Inspect the React component tree, props and hooks on pages that use React.
Form filling and clearing
Fill forms from MCP instructions or the side panel, and empty them again, with field detection and structured values.