# CSV slice rows

`csv-slice-rows` · version 1.0.0 · CSV & tables · free, no key needed

Take a contiguous window of CSV data rows by offset and limit, keeping the header.

**Use when you need to: csv slice rows · slice csv rows · csv row window.**

## Supported

- csv slice rows
- slice csv rows
- csv row window

## Not supported

- negative indexes
- wrap-around slicing
- sample random rows
- filter by key
- read files
- fetch urls

## Behavior

- offset and limit are JSON integers with Number.isInteger; each is between 0 and 5000 inclusive.
- Data rows are sliced as the half-open interval [offset, offset + limit) without wrapping or negative-from-end indexes.
- If offset is past the last data row, the header is kept and zero data rows are returned.
- An empty document without a header is rejected; a header-only document returns the header and rows_out 0 for any valid offset and limit.
- Cell strings are preserved without trimming, case folding, or type coercion.
- The first output header name may not begin with U+FEFF because it is ambiguous with a CSV byte-order mark.

## Input

- `csv` (string, required): max length 256000
- `offset` (integer, required): min 0; max 5000
- `limit` (integer, required): min 0; max 5000

## Output

- `csv` (string, required)
- `rows_in` (integer, required): min 0
- `rows_out` (integer, required): min 0

## Limits

- max input bytes: 256000
- max data rows: 5000
- max columns: 256
- max header name bytes: 256
- max offset: 5000
- max limit: 5000
- max output bytes: 256000

## Example

Request input:

```json
{
  "csv": "id,name\n1,Ada\n2,Lin\n3,Zoe\n",
  "offset": 1,
  "limit": 1
}
```

Response:

```json
{
  "result": {
    "csv": "id,name\n2,Lin\n",
    "rows_in": 3,
    "rows_out": 1
  }
}
```

## How to call it

### MCP

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

```json
{
  "id": "csv-slice-rows",
  "version": "1.0.0",
  "input": {
    "csv": "id,name\n1,Ada\n2,Lin\n3,Zoe\n",
    "offset": 1,
    "limit": 1
  }
}
```

### HTTP (no key)

```sh
curl -X POST https://computefirst.net/v1/tools/csv-slice-rows/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"csv":"id,name\n1,Ada\n2,Lin\n3,Zoe\n","offset":1,"limit":1}'
```

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

### CLI

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

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

## Related tools

- [CSV add row number](/tools/csv-add-row-number): Prepend a 1-based row_number column of canonical integer strings.
- [CSV row diff](/tools/csv-row-diff): Compare two CSV documents with identical headers by unique key tuples and report added, removed, and changed rows.
- [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 dedupe](/tools/csv-dedupe): Remove duplicate CSV data rows while preserving the first occurrence.
- [CSV group count](/tools/csv-group-count): Count CSV rows by exact named-column tuples in first-seen order.