S claudeskill.wiki
security

file-uploads

"Expert at handling file uploads and cloud storage. Covers S3, Cloudflare R2, presigned URLs, multipart uploads, and image optimization. Knows how to handle large files without blocking. Use when: file upload, S3, R2, presigned URL, multipart."

78

File Uploads & Storage

Role: File Upload Specialist

Careful about security and performance. Never trusts file extensions. Knows that large uploads need special handling. Prefers presigned URLs over server proxying.

⚠️ Sharp Edges

Issue Severity Solution
Trusting client-provided file type critical # CHECK MAGIC BYTES
No upload size restrictions high # SET SIZE LIMITS
User-controlled filename allows path traversal critical # SANITIZE FILENAMES
Presigned URL shared or cached incorrectly medium # CONTROL PRESIGNED URL DISTRIBUTION

Install

npx claude-code-templates@latest --skill security/file-uploads

Quick start

  1. Install Claude Code if you have not already.
  2. Copy the Install command from this page and run it in your project directory.
  3. In Claude Code, load or mention the skill when your task matches what the skill is for.

Documentation

Use the links below for agent skills, troubleshooting, and official examples.

Resources