Runtimes

Runtimes are host environments that consume repo-managed surfaces through native support, generated projections, plugin manifests, MCPHub endpoints, or Skills CLI installs.

compatibility truth

Runtime	Instructions	Skills	Tools	Hooks	Agents
Antigravity	generated	Skills CLI	MCP projection	limited	not primary
Claude Code	native import	plugin/Skills CLI	MCP	generated	native subagents
Codex	AGENTS.md + config	plugin/Skills CLI	MCPHub	generated	dynamic delegation
Crush	AGENTS.md	Skills CLI	MCP projection	limited	not primary
Cursor	rules + AGENTS.md	Skills CLI	MCPHub	native hooks	.cursor/agents
Gemini CLI	GEMINI.md	Skills CLI	MCP projection	generated	not primary
GitHub Copilot	generated instructions	Skills CLI	MCP projection	baseline hooks	Copilot-only agents
Grok Build	generated config	mirrored skills	MCPHub	generated	delegation
OpenCode	AGENTS.md	Skills CLI	MCPHub + plugins	generated	native agents

Fixture-backed detail

Use Harness Support for support tiers, fixture status, sync commands, rollback coverage, and validation commands.

AntigravityAdvanced Agentic Coding assistant.

Claude CodeAnthropic's official CLI for Claude.

CodexAutonomous coding workflows for command-line development.

CrushAutonomous development agent focused on fast terminal workflows.

CursorThe AI Code Editor.

Gemini CLIGoogle's command-line interface for Gemini.

GitHub CopilotYour AI pair programmer, right in your IDE.

Grok BuildxAI's agentic coding CLI with skills, MCP, and Claude Code compatibility.

OpenCodeNative AGENTS.md support plus repo-level OpenCode config and subagents.

Harness SupportFixture-backed support tiers and validation commands.

Sync ManifestGenerated surface projection and sync behavior.