What is antigravity-companion AGENTS.md?

Repository instructions for a JetBrains IDE plugin that connects the Antigravity command-line agent to IntelliJ-based editors. The plugin runs a local Model Context Protocol server, allowing the agent to inspect the active editor, open files, diagnostics, and other IDE state.

Use them when developing or maintaining the plugin, its local server, its command-line relay, IDE actions, settings, MCP tools, or configuration integration.

They explain the bridge between the command-line agent and the IDE, so changes can follow the repository's intended architecture. They also identify where the Java, Kotlin, settings, and service code live.

How matasarei/antigravity-companion configures Codex and OpenCode

Reuse

Borrowing it

Nothing to install: this file belongs to matasarei/antigravity-companion. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/matasarei/antigravity-companion/main/AGENTS.md

Clone the repo

git clone --depth 1 https://github.com/matasarei/antigravity-companion

Made for: Codex, OpenCode.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/matasarei/antigravity-companion/agents-md/github.svg)](https://agentmods.dev/instructions/matasarei/antigravity-companion/agents-md)

Your own site

<a href="https://agentmods.dev/instructions/matasarei/antigravity-companion/agents-md"><img src="https://agentmods.dev/badge/instructions/matasarei/antigravity-companion/agents-md/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/matasarei/antigravity-companion/agents-md"><img src="https://agentmods.dev/badge/instructions/matasarei/antigravity-companion/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 3,257 This file is loaded in full into every session.

When invoked 3,257 The same file — it is already loaded in full.

Security scan B 1 finding. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.03257	$0.03257
Opus 5	$0.01629	$0.01629
Sonnet 5	$0.00651	$0.00651
Haiku 4.5	$0.00326	$0.00326

Measured 5d ago against content hash 6bbb9441a822, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade B, and why

antigravity-companion AGENTS.md scanned grade B with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 5d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Reads agent configuration directoriesmediumAgent snooping

.claude/, .codex/, .gemini/ hold keys, settings and other credentials a mod has no legitimate need for.

- The plugin merges itself into `~/.gemini/config/mcp_config.json` so `agy`

AGENTS.md · 297 lines

How it starts

The opening of the file, as written. The whole thing — 297 lines — stays where its author put it; the contents beside it link to each section on GitHub.

AGENTS.md

Guidance for coding agents (and humans) working on this repository.

What this is

A JetBrains plugin that bridges the Antigravity CLI (agy) with IntelliJ-based IDEs (IntelliJ IDEA, PhpStorm, WebStorm, PyCharm, GoLand, RustRover, etc. — anything 2023.2+) through the Model Context Protocol (MCP).

The plugin runs a local TCP MCP server inside the IDE process.
A tiny pure-Java stdio↔TCP relay (StdioBridge) is invoked from a per-project script that the plugin generates.
The plugin merges itself into ~/.gemini/config/mcp_config.json so agy discovers it automatically.
Four tools are exposed: ide_get_active_editor, ide_get_open_files, ide_get_diagnostics, ide_open_file.

Plugin id: dev.matasar.antigravity-companion. License: MIT. End-user docs are in README.md.

Repository layout

src/main/
├── java/dev/matasar/antigravity/bridge/
│   └── StdioBridge.java                            ← pure-Java stdio↔TCP relay
└── kotlin/dev/matasar/antigravity/
    ├── action/StartSessionAction.kt                ← toolbar button
    ├── service/AntigravityCompanionService.kt      ← MCP server + tool implementations
    ├── settings/AntigravitySettings.kt             ← persistent app-level state (agy path)
    ├── settings/AntigravitySettingsConfigurable.kt ← Settings → Tools → Antigravity CLI Companion
    └── startup/AntigravityStartupActivity.kt       ← eager-init the service on project open
src/main/resources/
├── META-INF/plugin.xml                             ← manifest, services, actions, change notes
└── icons/, pluginIcon.svg                          ← toolbar + plugin icons
build.gradle.kts, gradle.properties, settings.gradle.kts
LICENSE  README.md  AGENTS.md

There is intentionally no agy-companion/ Go subproject, no EditorContextListener, no DiffViewerHandler, no ToolWindowFactory, no Ktor. If you find yourself adding any of these, stop and re-read the principles below.

Read the full file on GitHub · 297 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

5d ago Changed · +1 tokens per session 6bbb9441a822
10d ago First seen · 297 lines · 3,256 tokens per session scan B 8f7e13163093

Subscribe to this mod's changes

antigravity-companion AGENTS.md is an instructions file published in the GitHub repository matasarei/antigravity-companion (3 stars, last pushed 6d ago), licensed MIT. It adds 3,257 tokens to every session, about $0.0163 per session on Opus 5. A static security scan graded it B with 1 finding (reads agent configuration directories). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

Building agents ai-agents antigravity cli developer-tools gemini goland

next.js AGENTS.md

AGENTS.md instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.

vercel/next.js · 7,296 tokens

codex AGENTS.md

AGENTS.md instructions for openai/codex, covering rust/codex-rs, the codex-core crate, code review rules, crate api surface and model visible context.

openai/codex · 5,153 tokens

vscode buildNext.instructions.md

Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).

microsoft/vscode · 6,785 tokens

antigravity-companion: Instructions file for Codex