Antigravity CLI

Config name: antigravity

Google’s Antigravity CLI, invoked as agy. Antigravity ships three surfaces — the CLI, the IDE and the web app — which share the same configuration roots, so what symposium writes applies to all of them.

Skills

Hooks

Symposium merges a single named entry, symposium, into Antigravity’s hooks.json. Other entries in the file are left alone, and only symposium’s own is removed when the agent is unconfigured.

Events registered: PreToolUse, PostToolUse, PreInvocation, SessionStart, Stop.

Output format: JSON. Timeouts are in seconds (30 by default). Exit codes are ignored — only what a hook writes to stdout affects the agent. Context reaches the model at session start and on the first PreInvocation of a turn; after a tool call it does not (PostToolUse output carries nothing back), and on PreToolUse only a denial’s reason is shown.

Caveat: PreInvocation stands in for symposium’s user-prompt-submit because Antigravity has no prompt event. It fires before every model call, so symposium runs the prompt event only on the first invocation of a turn.

Caveat: in headless print mode (agy -p), Antigravity adopts no workspace unless it is given --add-dir <absolute path> — it cannot read project files and loads no project .agents/ configuration. A relative path is ignored. Ordinary interactive use is unaffected; this only matters for automation and CI.

MCP servers

Unlike Gemini CLI, MCP configuration lives in its own file rather than sharing one with hooks. agy mcp add has no scope flag and writes the global file.