MCP client integration

Twin Browser + Windsurf

Windsurf is Codeium’s AI-native editor, whose Cascade agent supports MCP servers. Servers are registered in `~/.codeium/windsurf/mcp_config.json` in the same `mcpServers` shape most clients use.

Get an API key Read the docs

MCP client4-step setupBearer key auth

How Twin plugs into Windsurf

Register the Twin server and Cascade can act on the web as part of an editing session — verify a deployed change, pull a fixture from behind a login, or reproduce a reported bug on a real page. The config is byte-identical to Cursor’s and Claude Desktop’s, because the server is the same stdio process in all three.

Twin is the browser execution layer your stack calls. The first run cold-compiles a skill via skill compilation; every similar request after that is matched from the cache and replayed deterministically, so your marginal cost per run trends toward zero rather than climbing with usage.

app.example.com

Windsurf → Twin

Receive goal from Windsurfdone
Compile DOM → token-efficient indexed statedone
Match the semantic dispatch cacherunning
Replay compiled skill — 0 LLM callsqueued

What you get through Windsurf

Every integration is a thin wrapper over the same execution layer, so the cache, the replay, and the corpus apply no matter how you call in.

Semantic dispatch cache

A re-phrased goal fuzzy-matches an already-compiled skill, so most calls never touch the LLM.

Deterministic replay

A compiled skill replays the exact action path with zero LLM calls — fast, repeatable, cheap.

Cross-tenant skill corpus

A skill compiled once can be safely reused across tenants, so the hit rate climbs as the network runs.

One Bearer key

Auth, usage-based billing, and an audit log run on every call — the same key works from every integration.

Wire it up

Drop Twin into Windsurf.

Copy, paste, and swap in your Bearer key. The first run compiles a skill; repeats match the semantic dispatch cache and replay deterministically.

~/.codeium/windsurf/mcp_config.jsonjson

{
  "mcpServers": {
    "twin-browser": {
      "command": "npx",
      "args": ["-y", "twin-browser-mcp"],
      "env": { "TWIN_API_KEY": "ab_live_…" }
    }
  }
}

// In Cascade:
//   "Use twin-browser to open the preview URL and screenshot the pricing page."

Base URL https://twin-browser.com/api/v1 · auth Authorization: Bearer ab_live_… · over MCP the same engine is run_goal, compile_skill and run_skill — the full tool table.

Get an API key
Create an ab_live_ key in the Twin dashboard under Keys & Secrets.
Open the MCP config
Edit ~/.codeium/windsurf/mcp_config.json (Windsurf’s MCP settings panel opens it for you).
Add the server
Add a twin-browser entry under mcpServers with the npx command and TWIN_API_KEY in env.
Refresh and use it
Refresh the server list; Cascade picks up the tools.

Read the Windsurf docs API reference

FAQ

Windsurf on Twin — common questions

Is the Windsurf config different from Cursor’s?

Only the file path. Both use the mcpServers shape with a command, args and env, and both launch the same twin-browser-mcp package over stdio.

Does Windsurf need Node?

Yes — Node 20 or newer, so npx can fetch and launch the server. There is nothing else to install.

Go deeper

Cursor

MCP client

Cursor is an AI-native code editor with a built-in agent that can call MCP tools. Servers are registered in `.cursor/mcp.json` for a project or `~/.cursor/mcp.json` globally, and their tools become available to the agent while you work.

Visual Studio Code

MCP client

VS Code’s Copilot agent mode supports MCP servers, configured in `.vscode/mcp.json` for a workspace or in your user profile. Note the shape difference: VS Code uses a top-level `servers` key where most other clients use `mcpServers`.

MCP (Model Context Protocol)

Protocol

MCP is an open protocol that lets an LLM application discover and call external tools over a standard interface. An MCP client — Claude Desktop, Claude Code, Cursor, Windsurf, VS Code, Cline — launches or connects to an MCP server, lists its tools, and invokes them on the model’s behalf, with no bespoke glue per app.

Wire up Windsurf in minutes.

Free to start. Usage-based credits from $29/mo — each call billed the higher of its flat action price or its metered cost.

Get an API key See pricing