Simple Data Comparator MCP

Simple toolset for performing comparison of JSON, XML, XLSX, CSV and text data in Actual-Expected format with different options.

Documentation

Agent-oriented reference for the simple-data-comparator-mcp MCP server. Each comparator compares an actual value against an expected template and returns pass/fail with structured difference lines on failure.

Tools

| MCP Tool | Doc | Use when | |---|---|---| | compare-json | json-comparator.md | Comparing JSON API responses, config objects, or structured data | | compare-xml | xml-comparator.md | Comparing XML documents, SOAP payloads, or config files | | compare-csv | csv-comparator.md | Comparing tabular CSV exports or reports | | compare-xlsx | xlsx-comparator.md | Comparing Excel workbook sheets | | compare-text | text-comparator.md | Exact line-by-line text comparison (logs, plain output) |

Common response shape

All tools return MCP content with this structure:

{
  "content": [{ "type": "text", "text": "<result message>" }],
  "isError": true | false
}

• Pass: isError: false, text is Validation passed.
• Fail: isError: true, text includes Validation failed. and difference lines (except text comparator, which does not expose diff details via MCP)

Agent workflow

1. Choose the tool that matches the data format you need to compare.
2. Prepare inputs — JSON/XML/CSV/text as strings; XLSX as workspace file paths (e.g. Templates/test/1.xlsx) or base64.
3. Call the MCP tool — for Excel use compare-xlsx with actual and template file paths.
4. Read isError — if true, parse the difference lines to explain what diverged.
5. Apply options when needed (e.g. strictMode for JSON, includeColumns for CSV, ignoreRowOrder for unordered row sets).

Discovering tools at runtime

Use MCP tool discovery (tools/list) to get live schemas. Tool names are stable: validate-json, validate-xml, validate-csv, validate-xlsx, validate-text.

Running

Build and start the stdio MCP server:

npm run build
npm start

The server communicates over stdin/stdout. Logs are written to stderr so they do not interfere with MCP protocol messages.

Cursor configuration

Add this to your Cursor MCP settings (.cursor/mcp.json):

{
  "mcpServers": {
    "simple-data-comparator-mcp": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "@ee_will_i/simple-data-comparator-mcp"
      ]
    }
  }
}

Replace the path with your local project path. Run npm run build before starting the server.