@dennisk2025/json-prettifier

json-prettifier

Accepts raw/minified JSON text and returns a formatted, pretty-printed version with customizable indentation. Useful for debugging, readability, and working with JSON data in Claude Desktop and other MCP-compatible tools.

Installation

You can use this server instantly without installation via npx:

npx @dennisk2025/json-prettifier

Or, install it globally:

npm install -g @dennisk2025/json-prettifier

Adding to Claude Desktop

Add the following to your Claude Desktop config file at:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json

Example configuration:

{
  "mcpServers": {
    "jsonprettifier": {
      "command": "npx",
      "args": ["@dennisk2025/json-prettifier"]
    }
  }
}

Usage

After Claude launches, type /jsonprettifier and you will have access to the following tool:

Tool: prettify-json

• Description: Takes a JSON string and formats it with the specified indentation level.

Parameters

• json_string (string, required): The minified or raw JSON string to format.
• indent (integer, optional, default=2): Number of spaces to use for indentation (0 returns the most compact form, maximum 8).

Example

Input:

Tool name: prettify-json

Arguments:

{
  "json_string": "{\"hello\":\"world\",\"foo\":[1,2,3]}",
  "indent": 4
}

Result:

{
    "hello": "world",
    "foo": [
        1,
        2,
        3
    ]
}

Error handling

If invalid JSON is supplied, the tool returns a clear error message ("Failed to parse JSON ..."). If you supply an argument outside the allowed indent range, it defaults to 2 spaces.

Full Tool List

• prettify-json
  • Parameters:
    • json_string (string, required): The minified or raw JSON string to format.
    • indent (integer, optional, default=2, min=0, max=8): Indent spaces.
  • Returns: Formatted, pretty-printed JSON as text.