# CSV dialect format

`csv-dialect-format` · version 1.0.0 · CSV & tables · free, no key needed

Format string rows as CSV for an explicit dialect, quoting a one-field empty record when it can.

**Use when you need to: format string rows with an explicit csv dialect · write rfc 4180 quoted csv fields · serialize string cells with a chosen delimiter.**

## Decide before calling

Read the [versioned contract](/v1/tools/csv-dialect-format/versions/1.0.0) and the supported scope below. Reuse `csv-dialect-format@1.0.0` when your input, required output and limits match it. Choose another approach for an unsupported operation.

## Explain the choice

"I can use `csv-dialect-format@1.0.0` for format string rows with an explicit csv dialect. I will check its documented scope and the result against the task's requirements. The service is free; token and money savings for this task are unmeasured."

## Supported

- format string rows with an explicit csv dialect
- write rfc 4180 quoted csv fields
- serialize string cells with a chosen delimiter
- emit a quoted empty csv field
- format quote-none csv or reject it
- render csv text from string records
- כתיבת שורות לטקסט מופרד

## Not supported

- write an excel workbook
- omit the final record separator
- emit an unquoted one-field empty record

## Behavior

- Every record, including the last, ends with the dialect record separator. quoting is minimal, all, or none. minimal quotes a field that contains the delimiter, the quote, CR, or LF. all quotes every field. none never quotes.
- A single empty field is written as a quoted empty field plus the separator, for example "" followed by LF. That text parses back to [[""]]. When quote is none or quoting is none, that record is unsupported_input with reason empty_field_needs_quote. Two empty fields stay a bare comma.
- escape double repeats the quote inside quotes. escape backslash prefixes a backslash to the delimiter, breaks, the quote, and itself when those characters must be escaped. A field that still cannot be represented is unsupported_input, not a best-effort line.
- header present writes the header array first and requires data rows of that width. Duplicate or empty header names are invalid_input. header absent rejects a header array. Cells stay strings: no trim and no Unicode normalization.
- Dialect key order is delimiter, quote, escape, record_separator, header. Records and fields keep input order. The same input always yields the same csv string.

## Input

- `dialect` (object, required)
- `quoting` (one of "minimal", "all", "none", required)
- `header` (array of string, optional): min items 1; max items 8; each min length 1; each max length 256
- `rows` (array of array of string, required): max items 64; each min items 1; each max items 8; each each max length 256

## Output

- `csv` (string, required): min length 1; max length 1024

## Limits

- max input bytes: 4096
- max records: 64
- max fields: 8
- max field bytes: 256
- max csv bytes: 1024
- max output bytes: 4096
- max depth: 8

## Example

Request input:

```json
{
  "dialect": {
    "delimiter": ",",
    "quote": "\"",
    "escape": "double",
    "record_separator": "\r\n",
    "header": "absent"
  },
  "quoting": "minimal",
  "rows": [
    [
      "aaa",
      "bbb",
      "ccc"
    ],
    [
      "zzz",
      "yyy",
      "xxx"
    ]
  ]
}
```

Response:

```json
{
  "result": {
    "csv": "aaa,bbb,ccc\r\nzzz,yyy,xxx\r\n"
  }
}
```

## How to call it

### MCP

Connect `https://computefirst.net/mcp` ([setup](/docs#connect)), then call `execute` with:

```json
{
  "id": "csv-dialect-format",
  "version": "1.0.0",
  "input": {
    "dialect": {
      "delimiter": ",",
      "quote": "\"",
      "escape": "double",
      "record_separator": "\r\n",
      "header": "absent"
    },
    "quoting": "minimal",
    "rows": [
      [
        "aaa",
        "bbb",
        "ccc"
      ],
      [
        "zzz",
        "yyy",
        "xxx"
      ]
    ]
  }
}
```

### HTTP (no key)

```sh
curl -X POST https://computefirst.net/v1/tools/csv-dialect-format/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"dialect":{"delimiter":",","quote":"\"","escape":"double","record_separator":"\r\n","header":"absent"},"quoting":"minimal","rows":[["aaa","bbb","ccc"],["zzz","yyy","xxx"]]}'
```

The machine-readable contract is at [/v1/tools/csv-dialect-format/versions/1.0.0](/v1/tools/csv-dialect-format/versions/1.0.0).

### CLI

```sh
node cli.mjs run csv-dialect-format 1.0.0 --input input.json --base-url https://computefirst.net
```

Get the client at [/clients/cli/](/clients/cli/).

## Related tools

- [CSV dialect parse](/tools/csv-dialect-parse): Parse CSV with an explicit dialect into string rows, keeping leading zeros and embedded breaks.
- [CSV dialect detect](/tools/csv-dialect-detect): Detect delimiter, quote, escape, record separator, and header for one rectangular CSV sample.
- [CSV fill defaults](/tools/csv-fill-defaults): Replace empty cells in named CSV columns with exact default strings.
- [CSV anti join](/tools/csv-anti-join): Keep left CSV rows whose exact key tuples do not appear in the right document.
- [CSV concat](/tools/csv-concat): Concatenate CSV documents that share identical headers, preserving document and row order.
- [CSV filter empty](/tools/csv-filter-empty): Keep or drop CSV rows whose named column is the empty string.