# Compare CSV

- Human page: https://happytails.ai/en/spreadsheet-tools/compare-csv/
- Markdown: https://happytails.ai/en/spreadsheet-tools/compare-csv.md
- Structured JSON: https://happytails.ai/agents/en/spreadsheet-tools/compare-csv/index.json
- Visibility: public

## Tool capabilities

| Property | Value |
| --- | --- |
| Tool ID | `compare-csv` |
| Category | spreadsheet-tools |
| Implementation | Registered implementation. Registration alone is not a production-quality guarantee. |
| Browser execution | Automatic updates after valid input or file selection. |
| Browser processing | Browser; see tool notes for network behavior. |
| HTTP API | /api/v1/tools/compare-csv/run |
| Browser-agent interface | run_current_tool |

### Inputs and settings

Text input: Your text.

Example or placeholder shown in the interface (not a validated fixture):

```text
Hello world!
```

Change the input or settings to update your result. Results update as you type. Up to 1,000,000 characters.

| Setting | Meaning | Control type | Default | Constraints |
| --- | --- | --- | --- | --- |
| `delimiter` | CSV separator | select | "," | Allowed: ,, ;, 	 |
| `other` | Second CSV | textarea | "" |  |

### HTTP contract

API calls process supplied data on the server. The website origin is `https://happytails.ai`. Server API hosting is not connected on the public website yet. Use your local server origin to test these requests.

```http
POST https://happytails.ai/api/v1/tools/compare-csv/run
Content-Type: application/json
```

[Detailed operation reference](https://happytails.ai/en/api/tools/compare-csv.md) · [Shared API guide](https://happytails.ai/en/api.md)

#### Limits

| Limit | Value |
| --- | --- |
| request_bytes | 8388608 |
| input_characters | 1000000 |
| files_bytes | 5242880 |
| max_files | 0 |
| timeout_seconds | 12 |

#### Complete input schema

```json
{
  "type": "object",
  "additionalProperties": false,
  "properties": {
    "input": {
      "type": "string",
      "maxLength": 1000000,
      "default": "",
      "description": "Plain text input. File tools use files instead unless otherwise documented."
    },
    "options": {
      "type": "object",
      "additionalProperties": false,
      "properties": {
        "delimiter": {
          "type": "string",
          "description": "CSV separator",
          "default": ",",
          "enum": [
            ",",
            ";",
            "\t"
          ]
        },
        "other": {
          "type": "string",
          "description": "Second CSV",
          "default": ""
        }
      }
    }
  }
}
```

#### Complete output schema

```json
{
  "type": "object",
  "required": [
    "tool",
    "result"
  ],
  "properties": {
    "tool": {
      "type": "string"
    },
    "result": {
      "type": "object",
      "required": [
        "text",
        "files"
      ],
      "properties": {
        "text": {
          "type": [
            "string",
            "null"
          ]
        },
        "data": {
          "description": "Parsed JSON when the textual result is JSON."
        },
        "name": {
          "type": "string"
        },
        "mime": {
          "type": "string"
        },
        "files": {
          "type": "array",
          "items": {
            "type": "object",
            "required": [
              "name",
              "mime",
              "bytes",
              "base64"
            ],
            "properties": {
              "name": {
                "type": "string"
              },
              "mime": {
                "type": "string"
              },
              "bytes": {
                "type": "integer"
              },
              "base64": {
                "type": "string",
                "contentEncoding": "base64"
              }
            }
          }
        }
      }
    }
  }
}
```

#### Error and retry handling

Failures return a non-200 status and `error.code` plus `error.message`. Correct invalid input before retrying; retry server-busy responses with bounded backoff. Returned files contain Base64 data, not persistent download URLs. Decode and inspect the output before treating conversion as successful. See the shared API guide for the complete status and timeout rules.

### Browser-agent workflow

1. Open the human page in a browser that supports WebMCP.
2. Discover the interface exposed by that page; use its actual schema.
3. Select files on the page first when the tool requires files.
4. Call `run_current_tool` with valid input and settings.
5. Inspect the returned result or error and the displayed output. Retrieve files from the displayed download links.

Calls do not automatically copy or download results. Browser permissions still apply. Interface availability alone is not proof of successful execution.

### Planning specification

Keyed row diff versus position diff; added/deleted/changed cells and download.

This describes intended requirements. Use the implementation notes, interface schema and observed output to determine current support.

### Complete machine-readable capability record

```json
{
  "id": "compare-csv",
  "category": "spreadsheet-tools",
  "built": true,
  "requirements": "Keyed row diff versus position diff; added/deleted/changed cells and download.",
  "implementation": {
    "fields": [
      {
        "key": "delimiter",
        "label": "CSV separator",
        "value": ",",
        "type": "select",
        "values": [
          ",",
          ";",
          "\t"
        ]
      },
      {
        "key": "other",
        "label": "Second CSV",
        "value": "",
        "type": "textarea"
      }
    ],
    "experience": {
      "automatic": true,
      "single": false,
      "label": "Your text",
      "placeholder": "Hello world!",
      "help": "Change the input or settings to update your result. Results update as you type. Up to 1,000,000 characters.",
      "action": null
    },
    "mode": "automatic",
    "interactive": false
  },
  "execution": "POST /api/v1/tools/compare-csv/run",
  "api": {
    "id": "compare-csv",
    "name": "Compare CSV",
    "category": "spreadsheet-tools",
    "description": "Keyed row diff versus position diff.",
    "notes": "",
    "human_path": "/en/spreadsheet-tools/compare-csv/",
    "method": "POST",
    "endpoint": "/api/v1/tools/compare-csv/run",
    "schema_url": "/api/v1/tools/compare-csv",
    "input_schema": {
      "type": "object",
      "additionalProperties": false,
      "properties": {
        "input": {
          "type": "string",
          "maxLength": 1000000,
          "default": "",
          "description": "Plain text input. File tools use files instead unless otherwise documented."
        },
        "options": {
          "type": "object",
          "additionalProperties": false,
          "properties": {
            "delimiter": {
              "type": "string",
              "description": "CSV separator",
              "default": ",",
              "enum": [
                ",",
                ";",
                "\t"
              ]
            },
            "other": {
              "type": "string",
              "description": "Second CSV",
              "default": ""
            }
          }
        }
      }
    },
    "output_schema": {
      "type": "object",
      "required": [
        "tool",
        "result"
      ],
      "properties": {
        "tool": {
          "type": "string"
        },
        "result": {
          "type": "object",
          "required": [
            "text",
            "files"
          ],
          "properties": {
            "text": {
              "type": [
                "string",
                "null"
              ]
            },
            "data": {
              "description": "Parsed JSON when the textual result is JSON."
            },
            "name": {
              "type": "string"
            },
            "mime": {
              "type": "string"
            },
            "files": {
              "type": "array",
              "items": {
                "type": "object",
                "required": [
                  "name",
                  "mime",
                  "bytes",
                  "base64"
                ],
                "properties": {
                  "name": {
                    "type": "string"
                  },
                  "mime": {
                    "type": "string"
                  },
                  "bytes": {
                    "type": "integer"
                  },
                  "base64": {
                    "type": "string",
                    "contentEncoding": "base64"
                  }
                }
              }
            }
          }
        }
      }
    },
    "processing": "Server; same transformation code as browser tools",
    "limits": {
      "request_bytes": 8388608,
      "input_characters": 1000000,
      "files_bytes": 5242880,
      "max_files": 0,
      "timeout_seconds": 12
    }
  },
  "agent_processing": "Server; same transformation code as browser tools",
  "browser_agent": {
    "supported": true,
    "name": "run_current_tool",
    "discovery": "WebMCP on the human page in a supporting browser",
    "verification": "See audit/API-AUDIT.md; availability is not verification"
  }
}
```

## Page guide

Keyed row diff versus position diff.

## Useful next steps

- [CSV remove duplicates](https://happytails.ai/en/data-tools/csv-remove-duplicates/): Remove duplicate CSV rows while keeping the first occurrence. ([Markdown](https://happytails.ai/en/data-tools/csv-remove-duplicates.md))

- [CSV join](https://happytails.ai/en/spreadsheet-tools/csv-join/): Inner/left/full joins on explicit keys. ([Markdown](https://happytails.ai/en/spreadsheet-tools/csv-join.md))

- [JSON to CSV](https://happytails.ai/en/data-tools/json-to-csv/): Convert JSON to CSV. ([Markdown](https://happytails.ai/en/data-tools/json-to-csv.md))

## How to use Compare CSV

1. Enter your text in the input field.
2. The result updates as you type. Adjust the available settings if needed.
3. Review the result, then use Copy result or a download link when available.

## Working with compare csv

Spreadsheet tasks involve values, formulas, data types and presentation. A conversion may preserve the displayed value without preserving the formula that produced it. Identifiers, dates and locale-specific decimal separators deserve special attention.

## Common questions

### Why do identifiers lose leading zeros?

A spreadsheet can interpret a text identifier as a number. Once 00123 is treated as 123, formatting may be needed to display zeros again. Preserve the original value as text when its exact representation matters.

### Does CSV keep formulas and multiple sheets?

CSV represents one flat table. It does not retain a workbook’s sheets, formatting or full formula behavior. Treat it as an exchange format for values and review how the receiving application interprets them.

Continue your workflow: [CSV remove duplicates](https://happytails.ai/en/data-tools/csv-remove-duplicates/), [CSV join](https://happytails.ai/en/spreadsheet-tools/csv-join/), [JSON to CSV](https://happytails.ai/en/data-tools/json-to-csv/).