io.github.bytedance/mcp-server-browser

Web Browser

Is the io.github.bytedance/mcp-server-browser MCP server down? No. It answered initialize and tools/list in the probe of 2026-10-31.

MCP server for browser use access

alive probed 2026-11-14 · unchanged since 2026-10-31

21tools

2.9ktokens in Claude Opus 5.5

1.4 %of Claude's 200k window

1.1×the median server

545 msto initialize

15 msto list tools

Run it: npx -y @agent-infra/mcp-server-browser@latest (stdio, probed in a container with the network off)
Host: npmjs.com
Reports itself as: Web Browser 1.2.29
Capabilities: completions, resources, tools
Instructions: none
Of a 1M window: 0.3 % of a 1M context window
Count: 2.9k tokens in Claude Opus 5.5, exact, measured 2026-10-17. With the Claude Code prefix mcp__…__ on each tool name: 3.1k. The o200k_base estimate is 1.6k. Counted again when the tool definitions change. Method.
Repository: https://github.com/bytedance/UI-TARS-desktop
Registry: active, updated 2025-09-09 · registry entry

Most expensive tools

The Claude column scales the o200k estimate of each tool by this server's ratio of exact to estimate, 1.81×.

Tool	≈ Claude tokens	o200k estimate	Share of this server
browser_press_key	533	294	19 %
browser_screenshot	308	170	11 %
browser_form_input_fill	263	145	9 %
browser_select	196	108	7 %
browser_click	170	94	6 %

Other registry entries on npmjs.com, the ones next to this name; all of them.

Servers that mention browser.

The result of the latest probe, the tool count and the token cost. The feed has an entry for every probe that changed them.

Stops answering, comes back, tool set or cost changes. One confirmation mail first, a stop link in every mail.