> ## Documentation Index
> Fetch the complete documentation index at: https://agents.nanonets.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Read File

> Returns the current text of an existing text file with 1-indexed line numbers.

Returns the current text of an existing text file with 1-indexed line numbers. Display name **"Read File"**. On by default for new agents.

Use this before `edit_file`: copy exact text (including whitespace) into `old_string`. Binary formats (`xlsx`, `docx`, `pdf`) belong with extraction tools, not here.

## Authentication and enablement

No integration. The file must already exist on the task (upload or `generate_file`). Default-on.

## Inputs

* `file_id` (required): UUID of the file.
* `offset` (optional): 1-indexed start line; default 1.
* `limit` (optional): max lines; default all.

## Output

File content prefixed with line numbers.

## Limits and side effects

* Text formats only: html, md, csv, txt, json, xml, svg, yaml.
* Read-only.

## Expected errors

* Invalid or unknown `file_id`.
* Negative `offset` / `limit`.
* Binary / unsupported format.