Install

Claude Code

Claude Code uses a plugin system with .claude-plugin/plugin.json manifests. Distribution via GitHub-hosted marketplace repos. All management through in-session /plugin slash commands.

From GitHub

Add the Subquadratic marketplace, then install the plugin.

Commands

/plugin marketplace add subquadratic-ai/subq-utility-plugin
/plugin install subq-utility@subquadratic
/reload-plugins

Local dev claude --plugin-dir ./subq-utility-plugin

Scopes User (all projects), Project (repo collaborators), Local (you only)

Auto-discovery skills/*/SKILL.md, hooks/hooks.json, .mcp.json, agents/, bin/

Manifest .claude-plugin/plugin.json

Codex CLI

Codex uses a plugin system with .codex-plugin/plugin.json manifests. Browse and install via the /plugins TUI, or add manually to config.toml.

INSTALL

Config

Add the plugin to your Codex configuration file.

~/.codex/config.toml

[plugins.subq-utility]
path = "https://github.com/subquadratic-ai/subq-utility-plugin"

TUI browser Run /plugins inside Codex CLI to browse and install

Skills format skills/*/SKILL.md with name/description frontmatter

Hooks hooks.json at plugin root — SessionStart, Stop, UserPromptSubmit

Manifest .codex-plugin/plugin.json

Gemini CLI

Gemini CLI uses “extensions” with a gemini-extension.json manifest. Install from GitHub via shell command. Tools exposed through MCP servers.

INSTALL

From GitHub

Install the extension directly from the repository.

Commands

gemini extensions install https://github.com/subquadratic-ai/subq-utility-plugin
gemini extensions install https://github.com/subquadratic-ai/subq-utility-plugin --auto-update

Local dev gemini extensions link .

Extension dir ~/.gemini/extensions/

Hook events BeforeAgent, AfterAgent, BeforeTool, AfterTool, OnUserInput

Manifest gemini-extension.json

Version pin --ref v1.2.0 flag on install

Compatibility Matrix

Side-by-side comparison of how each provider handles plugins, hooks, skills, and distribution.

Manifest

.claude-plugin/plugin.json

.codex-plugin/plugin.json

gemini-extension.json

Skills

skills/*/SKILL.md

MCP servers

Hook config

hooks/hooks.json

hooks.json (root)

settings.json

Hook events

SessionStart, Stop, PreCompact

SessionStart, Stop, UserPromptSubmit

BeforeAgent, AfterAgent, BeforeTool

Install

/plugin install

/plugins TUI

gemini extensions install

Distribution

GitHub marketplace repos

openai/plugins repo

GitHub URL

Local dev

--plugin-dir

config.toml

extensions link

Prerequisites

The plugin is a pure declaration shell—all hook logic lives in the SubQ CLI. You need the CLI installed and (optionally) the local server running.

SubQ CLI subq must be on PATH. SessionStart hook includes a command -v subq fallback.

Local server Optional. Hooks degrade gracefully if unreachable—blocking hooks timeout, non-blocking return {}.

Override path Set SUBQ_CODE_PATH env var to use a non-PATH CLI location.