name: sam-upload-file
description: Upload files to cloud storage and get a public URL. Supports Cloudflare R2, Vercel Blob, Backblaze B2, and AWS S3. Remembers your provider preference. Use when you need to upload local files for sharing or embedding.
metadata:
author: samhe
version: "1.0.0"

File Upload Skill

Upload any file to cloud storage and get a public URL.

Provider Selection

1. Check for explicit override

If the user mentions a specific provider (e.g. "upload to S3", "upload to Vercel"), skip the saved preference and use that provider directly.

Keyword mapping:
- "r2" or "cloudflare" → R2
- "vercel" or "blob" → Vercel Blob
- "b2" or "backblaze" → Backblaze B2
- "s3" or "aws" → AWS S3

2. Read saved preference

cat ~/.baoyu-skills/upload-config.json 2>/dev/null

Expected format: {"defaultProvider": "r2"} — valid values: r2, vercel, b2, s3

If a valid provider is saved, use it.

3. First run — ask the user

If no preference is saved, ask:

Which cloud storage provider would you like to use?
1. Cloudflare R2
2. Vercel Blob
3. Backblaze B2
4. AWS S3

Save the choice:

mkdir -p ~/.baoyu-skills && echo '{"defaultProvider": "CHOICE"}' > ~/.baoyu-skills/upload-config.json

4. Changing provider

If the user says "change provider", "switch provider", or similar, show the list again, save the new choice, and confirm.

Provider: Cloudflare R2

Setup

Credentials in ~/.baoyu-skills/.env:

R2_ACCESS_KEY_ID=...
R2_SECRET_ACCESS_KEY=...
R2_ENDPOINT=https://your-account-id.r2.cloudflarestorage.com
R2_BUCKET=your-bucket-name
R2_PUBLIC_URL=https://your-public-domain.com

If any are missing, tell the user which variables to add and where to find them in the Cloudflare dashboard (R2 > Manage API Tokens).

Dependencies (only if ${SKILL_DIR}/scripts/node_modules doesn't exist):

cd ${SKILL_DIR}/scripts && bun install

Upload

cd ${SKILL_DIR}/scripts && bun main.ts --file /absolute/path/to/file --json

With a custom key:

cd ${SKILL_DIR}/scripts && bun main.ts --file /path/to/file --key custom/path/file.ext --json

Output:

{
  "url": "https://your-domain.com/uploads/filename-1705123456789.ext",
  "key": "uploads/filename-1705123456789.ext",
  "bucket": "your-bucket",
  "size": 12345
}

Return the url to the user.

Provider: Vercel Blob

Setup

Check CLI: which vercel — if missing: npm i -g vercel

Credentials in ~/.baoyu-skills/.env:

BLOB_READ_WRITE_TOKEN=vercel_blob_rw_...

If missing, tell the user to get a token from the Vercel dashboard under Storage > Blob > Tokens.

Upload

FILENAME=$(basename "/path/to/file")
EXT="${FILENAME##*.}"
NAME="${FILENAME%.*}"
TIMESTAMP=$(date +%s%3N)
KEY="uploads/${NAME}-${TIMESTAMP}.${EXT}"

source ~/.baoyu-skills/.env && vercel blob put "$KEY" "/path/to/file" --token "$BLOB_READ_WRITE_TOKEN" --yes

The CLI prints the blob URL to stdout. Return it to the user.

Provider: Backblaze B2

Setup

Check CLI: which b2 — if missing: pipx install b2 (or pip install b2)

Credentials in ~/.baoyu-skills/.env:

B2_APPLICATION_KEY_ID=...
B2_APPLICATION_KEY=...
B2_BUCKET=your-bucket-name
B2_PUBLIC_URL=https://f000.backblazeb2.com/file/your-bucket

If missing, tell the user to get credentials from the Backblaze B2 dashboard under App Keys.

Upload

source ~/.baoyu-skills/.env
b2 account authorize "$B2_APPLICATION_KEY_ID" "$B2_APPLICATION_KEY"

FILENAME=$(basename "/path/to/file")
EXT="${FILENAME##*.}"
NAME="${FILENAME%.*}"
TIMESTAMP=$(date +%s%3N)
KEY="uploads/${NAME}-${TIMESTAMP}.${EXT}"

b2 file upload "b2://${B2_BUCKET}" "/path/to/file" "$KEY"

Construct URL: ${B2_PUBLIC_URL}/${KEY} — return it to the user.

Provider: AWS S3

Setup

Check CLI: which aws — if missing: brew install awscli

Credentials in ~/.baoyu-skills/.env:

AWS_ACCESS_KEY_ID=...
AWS_SECRET_ACCESS_KEY=...
AWS_S3_BUCKET=your-bucket-name
AWS_S3_REGION=us-east-1
AWS_S3_PUBLIC_URL=https://your-custom-domain.com

AWS_S3_PUBLIC_URL is optional. If not set, use: https://{bucket}.s3.{region}.amazonaws.com/{key}

Upload

FILENAME=$(basename "/path/to/file")
EXT="${FILENAME##*.}"
NAME="${FILENAME%.*}"
TIMESTAMP=$(date +%s%3N)
KEY="uploads/${NAME}-${TIMESTAMP}.${EXT}"

source ~/.baoyu-skills/.env && aws s3 cp "/path/to/file" "s3://${AWS_S3_BUCKET}/${KEY}" --region "$AWS_S3_REGION"

Construct URL: ${AWS_S3_PUBLIC_URL}/${KEY} (or standard S3 URL if no custom domain). Return it to the user.

Supported File Types

Images, videos, audio, documents, text, archives, and any other file type.

Error Handling

For any provider, if setup is incomplete (missing CLI tool or env vars), guide the user through the setup steps above before attempting the upload.