Archive Format

File Extension and MIME Type

Property	Value
File extension	`.ccpkg`
MIME type	`application/vnd.ccpkg+zip`
Magic bytes	`PK` (standard ZIP header, bytes `50 4B 03 04`)

Archive Requirements

A ccpkg archive is a standard ZIP file. The following requirements apply:

The archive MUST contain a manifest.json file at the archive root.
All paths within the archive MUST use forward slashes (/) as path separators.
The archive MUST NOT contain entries with paths that traverse outside the archive root (e.g., ../escape/file.txt). Installers MUST reject archives containing path traversal sequences.
The archive SHOULD be compressed using the DEFLATE algorithm.
Archives SHOULD NOT exceed 50 MB. Packages requiring large binary dependencies SHOULD use Mode 3 (referenced mcpb) to keep the archive small.
The archive filename SHOULD follow the convention {name}-{version}.ccpkg.

Directory Structure

example-plugin-1.2.0.ccpkg (ZIP)
├── manifest.json                   # REQUIRED — package manifest
├── skills/
│   └── skill-name/
│       ├── SKILL.md                # Agent Skills format
│       ├── scripts/
│       │   └── extract.py
│       └── references/
│           └── REFERENCE.md
├── agents/
│   └── agent-name/
│       └── AGENT.md
├── commands/
│   └── command-name.md
├── hooks/
│   └── hooks.json
├── scripts/
│   └── hook-handler.sh             # Backing scripts for hooks
├── mcp/
│   └── .mcp.json                   # MCP server config template
├── lsp/
│   └── .lsp.json                   # LSP server config template
├── instructions/
│   ├── base.md                     # Base instructions (shared across all hosts)
│   └── hosts/                      # Per-host overlay files
│       ├── claude-code.md           # Claude Code-specific overlay
│       ├── copilot-cli.md          # Copilot-specific overlay
│       └── gemini-cli.md           # Gemini-specific overlay
├── config.schema.json              # OPTIONAL — JSON Schema for config
├── icon.png                        # OPTIONAL — package icon (PNG, max 512x512)
└── LICENSE                         # OPTIONAL — license file

Only manifest.json is REQUIRED. All other files and directories are OPTIONAL and declared via the components field in the manifest.