mercat, home

mercat in Claude Code

A Claude Code plugin. It draws the mermaid blocks Claude writes as text diagrams, right in the reply.

Install the plugin ↓

Diagrams in replies
Claude writes a ```mermaid block, and you see a drawing. If mercat can't draw it, you see the block.
Wide flowcharts
They get cut off at », with a warning above.
/mercat <file>
Opens the file in a side pane.
/mercat
Lists the markdown and mermaid files Claude edited. Pick one to open it.
/mercat off, /mercat on
Shows the raw blocks, or draws them again.

A real session

Claude replies with a diagram. /mercat off shows the source. /mercat on draws it again.

Install

  1. Put mercat on your PATH

    The plugin runs the mercat binary. Without it, the plugin shows one hint per session and leaves diagrams as written. Other ways to install.

    brew install tawago/tap/mercat

  2. Add the plugin

    At the prompt of a Claude Code session:

    /plugin install mercat --marketplace tawago/mercat
In two steps, or from a shell

In two steps

/plugin marketplace add tawago/mercat
/plugin install mercat@mercat

From a shell

claude plugin install mercat --marketplace tawago/mercat

The plugin's version matches mercat's release version. If your mercat is older than the plugin, you get one upgrade hint at start. Tested with Claude Code 2.1.299. The plugin API is early access and may change between releases.