@arnilo/prism-antigravity-agent

Delegated agent adapter around the official Google Antigravity CLI (agy) with per-run Prism MCP capability exposure, custom hybrid tool policies, and AG-UI timeline projection.

Overview

@arnilo/prism-antigravity-agent enables Prism orchestrators and supervisors to delegate tasks to the official agy CLI using the host's authenticated Google AI Pro or AI Ultra subscription quota while exposing selected Prism tools via Model Context Protocol (MCP).

• CLI-Owned Agent Loop: agy owns planning, model selection, reasoning, subagents, and loop execution.
• Prism Capabilities & Security: State-changing workspace mutations (file edits, command execution, browser automation) route through authorized Prism MCP tools with secret redaction and policy enforcement.
• Zero Credential Handling: Prism never reads, stores, refreshes, or copies Antigravity OAuth tokens. Headless CLI runs use cached host credentials from interactive agy login.
• Safe Timeline Projection: Streams init, step_update, and result events into typed Prism AgentEvents and AG-UI activity snapshots without exposing unreleased internal chain-of-thought transcripts.

Installation

npm install @arnilo/prism-antigravity-agent

Prerequisites

Ensure the official Antigravity CLI (agy) is installed and authenticated on the host system:

agy login

Quick Start

Basic CLI Delegation

import { createAntigravityCliAgent } from "@arnilo/prism-antigravity-agent";

const agent = createAntigravityCliAgent({
  toolPolicy: "prism-mutators", // default: route state changes to Prism MCP
});

const result = await agent.run({
  prompt: "Analyze repository test suite and fix failing cases",
  cwd: process.cwd(),
});

console.log("Agent status:", result.status);
console.log("Response:", result.response);

Exposing Prism MCP Tools to Antigravity

import { createAntigravityCliAgent } from "@arnilo/prism-antigravity-agent";

const agent = createAntigravityCliAgent({
  tools: [
    {
      name: "run_build",
      description: "Runs npm run build",
      execute: async () => ({ toolCallId: "1", name: "run_build", content: [{ type: "text", text: "Build succeeded" }] }),
    },
  ],
  toolPolicy: "prism-mutators",
});

const result = await agent.run({
  prompt: "Run the build and verify clean output",
  cwd: "/path/to/workspace",
  onEvent: (event) => {
    console.log("Prism AgentEvent:", event.type);
  },
});

Supervisor Delegation Tool

import { createAntigravityCliAgent, createAntigravityDelegationTool } from "@arnilo/prism-antigravity-agent";

const agent = createAntigravityCliAgent();
const delegationTool = createAntigravityDelegationTool({ agent });

// Register in Prism ToolRegistry
registry.register(delegationTool);

Tool Policies

• "prism-mutators" (default): Denies overlapping Antigravity built-in mutators (run_command, write_to_file, replace_file_content, delete_file, rename_file, launch_browser, browser_action) and routes state mutations to authorized Prism MCP tools.
• "prism-only": Denies all mutator and read-only built-in tools, requiring all operations to execute through Prism MCP.
• Custom: Explicit { allowBuiltins: [...], denyBuiltins: [...] }.

License

MIT