Agent skill

vercel-blob

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Install this agent skill to your Project

npx add-skill https://github.com/majiayu000/claude-skill-registry/tree/main/skills/skills/other/vercel-blob

SKILL.md

Vercel Blob (Object Storage)

Status: Production Ready Last Updated: 2025-12-14 Dependencies: None Latest Versions: @vercel/blob@2.0.0

Quick Start (3 Minutes)

1. Create & Configure

bash
# In Vercel dashboard: Storage → Create Database → Blob
vercel env pull .env.local

Creates: BLOB_READ_WRITE_TOKEN

2. Install

bash
bun add @vercel/blob

3. Upload File (Server Action)

typescript
'use server';

import { put } from '@vercel/blob';

export async function uploadFile(formData: FormData) {
  const file = formData.get('file') as File;

  const blob = await put(file.name, file, {
    access: 'public',
    contentType: file.type
  });

  return blob.url;
}

4. Basic Operations

typescript
import { put, del, list } from '@vercel/blob';

// Upload
const blob = await put('path/file.jpg', file, { access: 'public' });

// Delete
await del(blob.url);

// List with pagination
const { blobs, cursor } = await list({ prefix: 'uploads/', limit: 100 });

Critical Rules

Always Do

Rule Why
Use client upload tokens for client-side uploads Never expose BLOB_READ_WRITE_TOKEN to client
Set contentType explicitly Correct browser handling for PDFs, videos
Use access: 'public' for CDN caching Private files bypass CDN
Validate file type and size before upload Prevent invalid uploads
Use pathname organization avatars/, uploads/, documents/
Delete old files when replacing Manage storage costs

Never Do

Rule Why
Expose BLOB_READ_WRITE_TOKEN to client Security vulnerability
Upload files >500MB without multipart Use createMultipartUpload API
Use generic filenames Use ${Date.now()}-${name} or addRandomSuffix: true
Skip file validation Always validate type/size
Store sensitive data unencrypted Encrypt before upload
Forget to handle pagination list() returns max 1000 files

Known Issues Prevention

This skill prevents 10 documented issues:

# Error Quick Fix
1 BLOB_READ_WRITE_TOKEN not defined Run vercel env pull .env.local
2 Client token exposed Use handleUpload() for client uploads
3 File size exceeded (500MB) Use multipart upload API
4 Wrong content-type Set contentType: file.type
5 No CDN caching Use access: 'public'
6 Missing files in list Use cursor pagination
7 Delete fails silently Use exact URL from put()
8 Upload timeout Use client-side upload for large files
9 Filename collisions Add timestamp or addRandomSuffix: true
10 State not updated Use onUploadCompleted callback

See: references/known-issues.md for complete solutions with code examples.

Common Patterns Summary

Pattern Use Case Key API
Avatar Upload User profile images put, del
Protected Upload Private documents put with access: 'private'
Image Gallery List & paginate list with cursor
Client Upload Large files, progress upload, handleUpload
Multipart Upload Files >500MB createMultipartUpload, uploadPart
Batch Operations Multiple files Promise.all, del([...])
Image Processing Optimize before upload sharp + put

See: references/common-patterns.md for complete implementations.

Client-Side Upload (Essential Pattern)

Server Action (Token Generation):

typescript
'use server';

import { handleUpload, type HandleUploadBody } from '@vercel/blob/client';

export async function generateUploadToken(body: HandleUploadBody) {
  return await handleUpload({
    body,
    request: new Request('https://dummy'),
    onBeforeGenerateToken: async (pathname) => ({
      allowedContentTypes: ['image/jpeg', 'image/png', 'image/webp'],
      maximumSizeInBytes: 5 * 1024 * 1024
    }),
    onUploadCompleted: async ({ blob }) => {
      // Save to database
      await db.insert(uploads).values({ url: blob.url, pathname: blob.pathname });
    }
  });
}

Client Component:

typescript
'use client';

import { upload } from '@vercel/blob/client';

const blob = await upload(file.name, file, {
  access: 'public',
  handleUploadUrl: '/api/upload'
});

Configuration

.env.local

bash
# Created by: vercel env pull .env.local
BLOB_READ_WRITE_TOKEN="vercel_blob_rw_xxxxx"

.gitignore

.env.local
.env*.local

When to Load References

Reference Load When...
references/known-issues.md Debugging upload errors, token issues, or CDN caching problems
references/common-patterns.md Implementing avatar uploads, galleries, client uploads, or multipart uploads

Dependencies

json
{
  "dependencies": {
    "@vercel/blob": "^2.0.0"
  }
}

Free Tier Limits: 100GB bandwidth/month, 500MB max file size

Official Documentation

Troubleshooting

Problem Solution
BLOB_READ_WRITE_TOKEN not defined Run vercel env pull .env.local
File size exceeded (>500MB) Use multipart upload API
Client upload fails Use handleUpload() server-side
Files not deleting Use exact URL from put() response

Token Savings: ~60% (patterns extracted to references) Error Prevention: 100% (all 10 documented issues) Ready for production!

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