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

Common response shape

All tools return MCP content with this structure:

{
  "content": [{ "type": "text", "text": "" }],
  "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.