Two minutes to your first transfer.

01MCP config

Add this to your MCP client's server config (e.g. Claude Desktop's claude_desktop_config.json). It runs npx @yafl/mcp under the hood – no install step, no build, and the published package resolves fresh every time.

{
  "mcpServers": {
    "yafl": {
      "command": "npx",
      "args": ["-y", "@yafl/mcp"],
      "env": {
        "YAFL_API_KEY": "yafl_your_key_here"
      }
    }
  }
}

No YAFL_API_KEY yet? The server still starts – each tool call returns a guided error pointing at yafl login or the env var, so a first-run agent never gets stuck on startup. Three tools ship: upload_file, download_file, get_status.

02CLI quickstart

Prefer a shell? Install @yafl/cli globally, one line either way:

# one-liner (checks Node, installs the CLI)
curl -fsSL https://yafl.dev/install.sh | sh

# or, if you already manage Node yourself
npm install --global @yafl/cli

yafl login
yafl put ./report.pdf
yafl get https://yafl.dev/t/{id}#{key} ./downloads
yafl status https://yafl.dev/t/{id}#{key}

put/get/status reuse the exact same client and encryption code as the MCP tools. Every command supports --json for machine-readable output and returns a stable exit code (0 ok, 2 usage, 3 auth, 4 not-found/expired) – safe to script against.

03How login works

Both the CLI and a fresh MCP server point you at the same device flow: yafl login requests a code, prints a verification URL and a short code, tries to open your browser automatically, and polls in the background until you approve it there. Approving needs a YAFL account with a verified email – signing in with an email link verifies you by construction. The minted API key is stored locally (mode 0600) – set YAFL_API_KEY directly instead if you're provisioning a headless agent or a VPS with no browser at all.

04REST API and Claude Desktop