Bkend Storage

What the source does

• FilesystemNone observedNo reads or writes in the source
• NetworkNone observedNo outbound calls in the source
• ShellNone observedNo commands run in the source
• DependenciesPinnedNothing floats
• SecretsNone foundNo keys in source

Five audit layers

Gates applied: no behavioural pass.

Audit 0.4.1 · source sha 1c89b145a4ba · 31 Oct 2026Report an issue or request a re-scan

• Publisherpopup-studio-ai GitHub organizationOwner of the repository this skill is read from
• Source folderpopup-studio-ai/bkit-claude-code/skills/bkend-storageThe exact folder we audited
• LicenceApache-2.0As the repository states it
• Commit pinned for this verdict1c89b145a4baA new audit runs when the source changes
• Repository statusNot archivedLast push 1 day ago
• Sandboxed runNot runSkills are read, not executed; layer L4 is skipped

Its description: bkend.ai file storage — upload (presigned URL), download (CDN), visibility levels, buckets. Triggers: bkend file, bkend upload, bkend download, bkend storage, bkend presigned URL

---
name: bkend-storage
classification: capability
classification-reason: Pattern guidance may overlap with model's built-in knowledge as it improves
deprecation-risk: medium
effort: medium
description: |
  bkend.ai file storage — upload (presigned URL), download (CDN), visibility levels, buckets.
  Triggers: bkend file, bkend upload, bkend download, bkend storage, bkend presigned URL
user-invocable: false
agent: bkit:bkend-expert
allowed-tools:
  - Read
  - Write
  - Edit
  - Glob
  - Grep
  - Bash
  - mcp__bkend__*
imports:
  - ${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/ww-w-ai/bkend-docs/main/en/storage/01-overview.md
- MCP Storage Guide: https://raw.githubusercontent.com/ww-w-ai/bkend-docs/main/en/mcp/07-storage-tools.md
- Full TOC: https://raw.githubusercontent.com/ww-w-ai/bkend-docs/main/SUMMARY.md

Excerpt, first 3,603 characters of SKILL.md, verbatim from the audited commit. It is text from someone else’s repository, quoted so you can judge it before your agent reads it.

git clone https://github.com/popup-studio-ai/bkit-claude-code
git -C bkit-claude-code checkout 1c89b145a4ba

Works in

1. 2026-10-31
   ✓SAFE B 89 / 100

   first audit · source 1c89b145a4ba

Questions about Bkend Storage

• github.com/popup-studio-ai/bkit-claude-code/tree/main/skills/bke — the audited source at commit 1c89b145a4ba and every finding aboveObserved · 31 Oct 2026

Spotted something wrong? Report a correction · Methodology