Google Antigravity SDK

The Google Antigravity SDK is a Python SDK for building AI agents powered by Antigravity and Gemini. It provides a secure, scalable, and stateful infrastructure layer that abstracts the agentic loop, letting you focus on what your agent does rather than how it runs.

Installation

pip install google-antigravity

Quickstart

Get started by running one of the examples/, such as the hello_world example with:

export GEMINI_API_KEY="your_api_key_here"
python ./examples/getting_started/hello_world.py

Gemini Enterprise Agent Platform (formerly Vertex AI)

To use the SDK with Gemini Enterprise Agent Platform (formerly Vertex AI), the SDK supports two authentication modes:

1. Express Mode (API Key)

For fast setup without requiring Google Cloud projects, regional configuration, or Application Default Credentials (ADC), provide an API key with vertex=True:

from google.antigravity import Agent, LocalAgentConfig

config = LocalAgentConfig(
    vertex=True,
    api_key="your_api_key_here",
)

async with Agent(config) as agent:
    response = await agent.chat("Hello!")
    print(await response.text())

2. Standard Mode (Project & Location with ADC)

For enterprise deployments routing to regional endpoints, configure LocalAgentConfig with vertex=True, project, and location. By default, this mode authenticates via Application Default Credentials (ADC).

from google.antigravity import Agent, LocalAgentConfig

config = LocalAgentConfig(
    vertex=True,
    project="your-gcp-project",
    location="us-central1",
)

async with Agent(config) as agent:
    response = await agent.chat("Hello!")
    print(await response.text())

Alternatively, you can leave these fields unset in LocalAgentConfig and export the environment variables instead:

# Either GOOGLE_GENAI_USE_VERTEXAI or GOOGLE_GENAI_USE_ENTERPRISE enable Vertex.
export GOOGLE_GENAI_USE_VERTEXAI=True
export GOOGLE_CLOUD_PROJECT="your-gcp-project"
export GOOGLE_CLOUD_LOCATION="us-central1"

Explicit kwargs always take precedence over env vars.

Ensure you have authenticated locally before running the agent in Standard Mode:

gcloud auth application-default login

See vertex.py for a complete example.

Concepts

Simple Agent

The Agent class is the easiest way to get started. It manages the full lifecycle — binary discovery, tool wiring, hook registration, and policy defaults — behind a single async context manager.

The system_instructions parameter is optional.

import asyncio
from google.antigravity import Agent, LocalAgentConfig

async def main():
    config = LocalAgentConfig(
        system_instructions="You are an expert assistant for codebase navigation.",
        # api_key="your_api_key_here",
    )
    async with Agent(config) as agent:
        response = await agent.chat("What files are in the current directory?")
        print(await response.text())

async def run():
    await main()

if __name__ == "__main__":
    asyncio.run(run())

Streaming Responses

To stream agent output in real-time (e.g., for fluid UI or console applications), simply iterate over the ChatResponse object using an async for loop. The stream wrapper natively yields conversational str text tokens as they arrive, with zero network overhead:

import asyncio
import sys
from google.antigravity import Agent, LocalAgentConfig

async def main():
    config = LocalAgentConfig()
    async with Agent(config) as agent:
        # Returns instantly — does not block
        response = await agent.chat("Write a short poem about space.")

        async for token in response:
            sys.stdout.write(token)
            sys.stdout.flush()
        print()

asyncio.run(main())

Sugared Thoughts & Tool Call Streams (Advanced)

For more complex use cases, you can also stream internal model reasoning/thinking or intercept tool call dispatches in real-time using dedicated async stream properties:

# 1. Stream reasoning/thinking deltas
async for thought in response.thoughts:
    show_thinking_bubble(thought)

# 2. Stream strongly-typed ToolCall events
async for call in response.tool_calls:
    show_executing_spinner(call.name)

By default, Agent runs in read-only mode for safety. Pass capabilities=CapabilitiesConfig() to enable all tools (including writes).

Interactive Loop

from google.antigravity import LocalAgentConfig, CapabilitiesConfig
from google.antigravity.utils.interactive import run_interactive_loop

config = LocalAgentConfig(
    # api_key="your_api_key_here",
    capabilities=CapabilitiesConfig(),
)
await run_interactive_loop(config)

Advanced Usage with Conversation

For full control over the connection lifecycle, use Conversation with a ConnectionStrategy directly. Conversation is a stateful session that accumulates step history, provides a chat() convenience method, and exposes state introspection:

import asyncio
from google.antigravity.connections.local import LocalConnectionStrategy
from google.antigravity.conversation.conversation import Conversation
from google.antigravity.tools.tool_runner import ToolRunner

async def main():
    tool_runner = ToolRunner()
    strategy = LocalConnectionStrategy(
        tool_runner=tool_runner,
    )

    async with Conversation.create(strategy) as conversation:
        # High-level: one-call send + collect
        response = await conversation.chat("What files are here?")
        print(await response.text())

        # Step history accumulates automatically
        print(f"Total steps: {len(conversation.history)}")
        print(f"Turns: {conversation.turn_count}")
        print(f"Last response: {conversation.last_response}")

        # Low-level: streaming steps
        await conversation.send("Tell me more.")
        async for step in conversation.receive_steps():
            if step.is_complete_response:
                print(step.content)

asyncio.run(main())

Features

Multimodal Ingestion

Pass rich multimedia file attachments (images, videos, audio, and documents) to the agent alongside textual instruction prompt lists.

You can attach assets directly using content classes (perfect for in-memory bytes) or conveniently from a filesystem path (which automatically resolves types and guesses MIME formats):

from google.antigravity import Agent, LocalAgentConfig
from google.antigravity.types import Image, from_file

config = LocalAgentConfig(system_instructions="You are an expert software architect.")
async with Agent(config) as agent:
    # 1. Flat filesystem shortcut (automatically resolves as types.Document)
    pdf_spec = from_file("spec.pdf")

    # 2. Direct constructor instantiation (perfect for in-memory raw bytes)
    chart_image = Image(
        data=b"raw_png_bytes_here",
        mime_type="image/png",
        description="Architecture blueprint"
    )

    # Send a mixed list of text instructions and content classes
    prompt = [
        "Analyze this chart against the specification and list three security vulnerabilities:",
        chart_image,
        pdf_spec
    ]
    response = await agent.chat(prompt)
    print(await response.text())

Custom Tools

Register Python functions as tools that the agent can call:

def get_weather(city: str) -> str:
    """Returns the current weather for a city."""
    return f"It's sunny in {city}."

config = LocalAgentConfig(
    tools=[get_weather],
)
async with Agent(config) as agent:
    response = await agent.chat("What's the weather in Tokyo?")

MCP Integration

Connect to external MCP servers and expose their tools to the agent:

from google.antigravity import Agent, LocalAgentConfig
from google.antigravity.types import McpStdioServer

config = LocalAgentConfig(
    mcp_servers=[McpStdioServer(name="my_server", command="npx", args=["my-mcp-server"])],
)
async with Agent(config) as agent:
    response = await agent.chat("Use the MCP tools to help me.")

Hooks and Policies

Control agent behavior with a declarative policy system:

from google.antigravity import LocalAgentConfig, CapabilitiesConfig
from google.antigravity.hooks.policy import deny, allow, ask_user, enforce
from google.antigravity.utils.interactive import run_interactive_loop

policies = [
    deny("*"),                          # Block all tools by default
    allow("view_file"),                 # Allow reading files
    ask_user("run_command", handler=my_handler),  # Ask before running commands
]

config = LocalAgentConfig(
    capabilities=CapabilitiesConfig(),
    policies=policies,
)
await run_interactive_loop(config)

Triggers

Run background tasks that react to external events and push messages into the agent:

from google.antigravity import LocalAgentConfig
from google.antigravity.triggers import every
from google.antigravity.utils.interactive import run_interactive_loop

async def check_status(ctx):
    await ctx.send("Check the deployment status.")

config = LocalAgentConfig(
    triggers=[every(60, check_status)],
)
await run_interactive_loop(config)

Local AI Models

The Antigravity SDK supports local, offline agentic workflows powered by Gemma 4 and LiteRT-LM. By pairing your SDK scripts with local models, you can run LLM-driven tasks completely offline.

Prerequisites and Installation

First, it is recommended to create and activate a virtual environment:

python3 -m venv .venv
source .venv/bin/activate

Next, install the Antigravity SDK along with LiteRT-LM:

pip install google-antigravity litert-lm

Import the Gemma 4 26B MoE model. Take note of the imported model path (e.g. on MacOS, typically models are imported to USER/.litert-lm/models):

litert-lm import \
  --from-huggingface-repo=litert-community/gemma-4-26B-A4B-it-litert-lm \
  gemma-4-26B-A4B-it-gpu.litertlm \
  gemma4-26b

Quick Start for Local Models:

import asyncio
import os
from google.antigravity import Agent, LiteRTAgentConfig

# Point directly to the locally imported LiteRT-LM model path
MODEL_PATH = os.path.expanduser("~/.litert-lm/models/gemma4-26b/model.litertlm")

async def main():
    print(f"Using local LiteRT model: {MODEL_PATH}")
    config = LiteRTAgentConfig(
        model_path=MODEL_PATH,
    ).lightweight()

    async with Agent(config) as agent:
        response = await agent.chat("What files are in the current directory?")
        async for token in response:
            print(token, end="", flush=True)

if __name__ == "__main__":
    asyncio.run(main())

Architecture

The SDK follows a three-layer architecture:

Component Documentation

For more detailed documentation on specific components, see:

• Agent — High-level, batteries-included entry point.
• Connections — Transport and backend abstraction.
• Conversation — Stateful session management.
• Hooks — Agent lifecycle interception and policies.
• MCP — Model Context Protocol integration.
• Tools — In-process tool execution.
• Triggers — Background tasks and external events.

License

Apache License 2.0