Reverse Engineering Antigravity

Knowledge Base

• Identity & Core Mission - Who it is and how it operates.
• Tools Reference - A guide to its capabilities and toolset.
• Workflow & Agentic Mode - Understanding the "Task View" and artifacts.
• Browser Automation - Details on the browser subagent.

Goals

1. Reverse engineer Antigravity and learn things in reverse order.
2. Explore agent communication and implementation details.
3. Explore browser automation.

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Identity: Antigravity

Who is Antigravity?

Antigravity is an agentic AI coding assistant designed by the Google Deepmind team and released on 18th November 2025.

Operational Constraints

• Workspace: It can only access files in the specified active workspaces (e.g., /home/ravi/Desktop/antigravity).
• Internal Memory: It uses /home/ravi/.gemini for internal state and artifacts, but avoids writing project code there.
• Communication: When in "Agentic Mode" (focusing on a task), it communicates primarily through notify_user to minimize noise, only surfacing for reviews or critical questions.

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Tools

Antigravity possesses a suite of tools to interact with the file system, terminal, and browser.

File System Operations

• view_file / view_file_outline: Read file contents and structure.
• write_to_file: Create new files.
• replace_file_content / multi_replace_file_content: Precise editing of existing files.
• list_dir: Explore directory contents.
• find_by_name / grep_search: Innovative search capabilities.

System & Terminal

• run_command: Execute shell commands (requires user approval).
• command_status / read_terminal: Monitor command output.
• send_command_input: Interact with running processes.

Analysis & Communication

• codebase_search: Semantic search for code snippets.
• notify_user: The primary channel for updates and review requests during active tasks.
• task_boundary: Manages the "task view" UI to group related actions.

Web & Browser

• read_url_content: Fetch static web content.
• browser_subagent: Full browser control for complex interactions.

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Workflow & Agentic Mode

Antigravity operates in a structured "Agentic Mode" to handle complex tasks without overwhelming the user.

The Loop

1. Task Boundary: Defines a high-level task using task_boundary. This creates a UI block in the chat.
2. Iterative Work: Performs file edits, command runs, and analysis.
3. Updates: Periodically updates the task status to reflect progress.
4. Completion: Uses notify_user to exit the task mode and return control to the user.

Artifacts

It maintains persistent documents to track state across the conversation. These live in a dedicated "brain" directory (/home/ravi/.gemini/antigravity/brain/...).

• task.md: A living checklist of the current mission.
• implementation_plan.md: Design documents created during the PLANNING phase.
• walkthrough.md: Proof-of-work documents created during the VERIFICATION phase to show what was tested.

Modes

• PLANNING: Researching and designing. Output: implementation_plan.md.
• EXECUTION: Writing code. Output: Source code changes.
• VERIFICATION: Testing changes. Output: walkthrough.md.

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Browser Automation

For tasks involving web interaction, Antigravity can deploy a specialized Browser Subagent.

Capabilities

• Navigation: Open URLs, click links, navigate usage.
• Interaction: Click buttons, type text, fill forms.
• Observation: Read the DOM, capture screenshots.
• Recording: All sessions are recorded as videos (saved as artifacts).

Usage

It uses the browser_subagent tool. This agent has its own limited set of tools specifically for browser control.

Limitations

• The subagent is a separate entity; Antigravity provides it with a high-level task.
• It is best for verification (e.g., "Login and check if the dashboard loads") or data extraction.