🐀 rat

Quick Start

Install rat and Python support

Terminal
curl -fsSL https://runanything.dev/install.sh | sh
rat install py

Start a REPL

Terminal
rat py
In [1]: import pandas as pd
In [2]: df = pd.read_csv("sales.csv")
In [3]: df.shape
(1000, 12)

Leave it open.

Connect Claude Desktop

Check the kernel’s URL:

Terminal
rat status -v

Add it to your Claude Desktop config (~/Library/Application Support/Claude/claude_desktop_config.json on macOS):

{
  "mcpServers": {
    "python": { "url": "http://127.0.0.1:8717/mcp" }
  }
}

Restart Claude Desktop and say:

“Describe the dataframe I just loaded.”

Claude sees the same df — same kernel, same namespace. No copy-paste, no export.

Run one-liners

From another terminal:

Terminal
rat run py 'print(df.columns.tolist())'
['date', 'product', 'region', 'revenue', ...]

Inspect state

Terminal
rat look py
Variables:
  df    DataFrame  (1000, 12)  780KB
  pd    module     pandas
Terminal
rat look py --at df
pandas.DataFrame · (1000, 12) · 780KB
Columns: date (datetime64), product (object), region (object), revenue (float64), ...
Head:
  date        product   region   revenue
  2024-01-01  Widget A  East     1234.56
  ...

Next steps