Pier_v1/.hmcmkit/knowledge/skills/bkend-storage/SKILL.md

name, classification, classification-reason, deprecation-risk, description, user-invocable, agent, allowed-tools, imports

name	classification	classification-reason	deprecation-risk	description	user-invocable	agent	allowed-tools	imports
bkend-storage	capability	Pattern guidance may overlap with model's built-in knowledge as it improves	medium	bkend.ai file storage — upload (presigned URL), download (CDN), visibility levels, buckets. Triggers: bkend file, upload, download, presigned URL, storage, 파일 업로드, 스토리지.	false	hmcmkit:bkend-expert	Read Write Edit Glob Grep Bash mcp__bkend__*	${PLUGIN_ROOT}/templates/shared/bkend-patterns.md

bkend.ai Storage Guide

Upload Methods

Method	Use Case	Process
Single	Normal files	Presigned URL -> PUT upload -> Register metadata
Multiple	Multiple files	Repeat single upload
Multipart	Large files	Initialize -> Part URLs -> Complete

Presigned URL

• Validity: 15 minutes
• PUT method with file binary
• Content-Type header required

File Visibility (4 levels)

Level	Access	URL Type
public	Anyone	CDN URL (no expiry)
private	Owner only	Presigned URL (1 hour)
protected	Authenticated users	Presigned URL (1 hour)
shared	Specified targets	Presigned URL (1 hour)

Size Limits

Category	Max Size
Images	10 MB
Videos	100 MB
Documents	20 MB

Storage Categories

images, documents, media, attachments

MCP Storage Workflow

bkend MCP does NOT have dedicated storage tools. Use this workflow:

1. Search docs: search_docs with query "file upload presigned url"
2. Get examples: search_docs with query "file upload code examples"
3. Generate code: AI generates REST API code for file operations

Searchable Storage Docs

Doc ID	Content
7_code_examples_data	CRUD + file upload code examples

REST Storage API

Method	Endpoint	Description
POST	/v1/files/presigned-url	Generate presigned URL
POST	/v1/files	Register metadata (complete upload)
GET	/v1/files	File list
GET	/v1/files/:fileId	File detail
PATCH	/v1/files/:fileId	Update metadata
DELETE	/v1/files/:fileId	Delete file
POST	/v1/files/:fileId/download-url	Generate download URL

Multipart Upload (Large Files)

Method	Endpoint	Description
POST	/v1/files/multipart/init	Initialize multipart upload
POST	/v1/files/multipart/presigned-url	Get part upload URL
POST	/v1/files/multipart/complete	Complete multipart upload
POST	/v1/files/multipart/abort	Abort multipart upload

Upload Flow (Single File)

1. POST /v1/files/presigned-url -> { url, fileId }
2. PUT {url} with file binary + Content-Type header
3. POST /v1/files with { fileId, filename, contentType, size, visibility }

Multipart Upload Flow (Large File)

1. POST /v1/files/multipart/init -> { uploadId }
2. POST /v1/files/multipart/presigned-url -> [{ partNumber, url }]
3. PUT each part URL with file chunk
4. POST /v1/files/multipart/complete -> { file }

Official Documentation (Live Reference)

For the latest storage documentation, use WebFetch:

• Storage Overview: https://raw.githubusercontent.com/popup-studio-ai/bkend-docs/main/en/storage/01-overview.md
• MCP Storage Guide: https://raw.githubusercontent.com/popup-studio-ai/bkend-docs/main/en/mcp/07-storage-tools.md
• Full TOC: https://raw.githubusercontent.com/popup-studio-ai/bkend-docs/main/SUMMARY.md