Your agent opens the site and tests what it wrote.

How an agent gets a browser.

1. You turn it on. In Preferences, under “Project browser”, check “Let agents use the browser” and enter your site's address. The default is http://localhost:3000.
2. You open an agent. Tactyn builds that session's configuration and starts the agent with the browser MCP server already attached.
3. The agent is told. For Claude Code, Tactyn adds an instruction saying where the site runs and which tools to use. For the others, the address is in the TACTYN_NAVEGADOR_URL variable.
4. It tests. It opens the page, clicks, fills in fields, reads the console and network, and tells you what it saw.

Two servers, whichever you pick.

Tactyn uses open MCP servers, run with npx: chrome-devtools-mcp and @playwright/mcp. The first is selected by default, and you can use either one or both. Node must be installed.

By default each session opens an isolated browser, with none of your cookies or history. If the site needs a login, turn on “Keep login between sessions”: the profile lives in a project folder, .tactyn/browser, separate for each pane and deleted when the session ends.

What it does

• Works with Claude Code, Codex and OpenCode.
• Applies per session: nothing is written to the agent's or the repository's config files.
• Applies to the next agent panes you open.
• Shows a warning if Node can't be found.

What it doesn't do

• Doesn't work with Antigravity CLI yet: it has no per-session configuration, and the app tells you so.
• Doesn't start your dev server: the site must already be running at the address you gave.
• Isn't on by default: you choose per project.

The address can be any http:// or https:// URL, including a staging environment online. What the agent does with the browser depends on the tools of the MCP server you chose, and Tactyn doesn't restrict that.

The browser is part of the Free plan, along with terminals and agents.