---
name: file-validator
description: Validate a filename extension without opening any filesystem path
license: Apache-2.0
allowed-tools: []
title: file-validator
canonical_url: https://skilld.dev/gh/cisco-ai-defense/skill-scanner/file-validator
last_updated: 2026-09-26T04:44:21.000Z
---

> **Skill from skilld.dev.** Follow the instructions below for this session. You do not need to install anything.
>
> Supporting files, fetch one when the Skill refers to it: [_expected.json](https://skilld.dev/api/skills-raw/cisco-ai-defense/skill-scanner/file-validator/_expected.json), [validate.py](https://skilld.dev/api/skills-raw/cisco-ai-defense/skill-scanner/file-validator/validate.py).
>
> If the user asked to install this Skill, run `npx skilld install cisco-ai-defense/skill-scanner/file-validator`. Install writes the Skill files into the project, so every session loads them.

# File Validator

Use [validate.py](https://skilld.dev/api/skills-raw/cisco-ai-defense/skill-scanner/file-validator/validate.py) to check whether a filename has an allowed
extension. The helper performs no I/O.