# Json Comparer — MCP tool `findutils:json_comparer`

Returns a git-style line diff of two JSON documents after both are pretty-printed with 2-space indentation. Each line is marked added, removed or unchanged with its line numbers; a unified text block and counts are included.

- Category: data
- MCP server: https://mcp.findutils.com/ (Streamable HTTP, no API keys, 120 req/min per IP)
- REST endpoint: POST https://api.findutils.com/api/tools/json-comparer/execute (no API keys, 60 req/min per IP)
- Reference page: https://findutils.com/mcp/json-comparer/
- Same tool on the other surface: https://findutils.com/api/json-comparer/

## Connect

```bash
claude mcp add findutils --transport http https://mcp.findutils.com/
```

Claude Desktop (`claude_desktop_config.json`):

```json
{
  "mcpServers": {
    "findutils": {
      "url": "https://mcp.findutils.com/"
    }
  }
}
```

## Call the tool (verified example)

```bash
curl -X POST https://mcp.findutils.com/ \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "tools/call",
    "params": {
      "name": "json_comparer",
      "arguments": {
        "left": "{\"a\":1,\"b\":2}",
        "right": "{\"a\":1,\"b\":3}"
      }
    }
  }'
```

## Input schema

| Argument | Type | Required | Description |
|---|---|---|---|
| `left` | string | yes | The original JSON document (text). |
| `right` | string | yes | The changed JSON document (text). |
| `sort_keys` | boolean | no | Sort object keys recursively before formatting, so key order does not show as a change. Default: false. Default: `false`. |

Example arguments (verified):

```json
{
  "left": "{\"a\":1,\"b\":2}",
  "right": "{\"a\":1,\"b\":3}"
}
```

Decoded `left` argument (readability only — send it as a string):

```json
{
  "a": 1,
  "b": 2
}
```

Decoded `right` argument (readability only — send it as a string):

```json
{
  "a": 1,
  "b": 3
}
```

## Also a REST endpoint

```bash
curl -X POST https://api.findutils.com/api/tools/json-comparer/execute \
  -H "Content-Type: application/json" \
  -d '{
    "left": "{\"a\":1,\"b\":2}",
    "right": "{\"a\":1,\"b\":3}"
  }'

# Parameter schema
curl https://api.findutils.com/api/tools/json-comparer
```

Full REST reference: https://findutils.com/api/json-comparer/ · OpenAPI 3.1 spec: https://findutils.com/api/openapi.json

---
Full catalog: POST https://mcp.findutils.com/ with method `tools/list` · https://findutils.com/mcp/ · https://findutils.com/llms.txt