Does Ultracite work with Antigravity IDE?

Yes. npx ultracite init --editors antigravity writes .vscode/settings.json for Oxlint and Oxfmt, Biome, or ESLint and Prettier. It installs the matching extension from Open VSX with the IDE’s antigravity-ide command.

Is Antigravity IDE the same as Antigravity 2.0?

No. Since May 2026, Antigravity 2.0 is a standalone app for running agents that works independently of an IDE, and Antigravity IDE is the editor, installed separately. Ultracite’s antigravity editor setup is for the IDE.

Does Antigravity IDE read AGENTS.md?

Yes, alongside GEMINI.md, since 1.20.5. It loads AGENTS.md at the workspace root and in each folder between a file the agent touches and the root, plus ~/.gemini/AGENTS.md for every project.

Why didn’t the Biome extension install in Antigravity?

init installs it with antigravity-ide --install-extension only when it creates .vscode/settings.json, and only if antigravity-ide is on your PATH. Otherwise, install biomejs.biome from the Extensions view: Antigravity searches Open VSX, where Biome publishes it.

Does Antigravity’s agent see Oxlint errors?

Its edit tools take a TargetLintErrorIds argument for fixing specific lint errors, so it can work through the ones your Oxc extension reports. For a full report, it can run npx ultracite check in the terminal.

Where does Antigravity IDE load skills from?

From .agents/skills/ in the workspace, where init installs the Ultracite skill, and from ~/.gemini/config/skills/ for every project. The older ~/.gemini/antigravity/skills/ still works.

Antigravity IDE, with AGENTS.md in every folder

ultracite init --editors antigravity writes .vscode/settings.json, so Antigravity IDE formats on save and applies safe fixes through Oxc, Biome or ESLint, and installs the extension from Open VSX with antigravity-ide. Its agent loads AGENTS.md folder by folder, and its edit tools can aim at the lint errors your extension reports, by ID.

Antigravity IDE by GoogleChecked against Antigravity IDE 2.5.5

{
  "editor.defaultFormatter": "esbenp.prettier-vscode",
  "editor.formatOnPaste": true,
  "editor.formatOnSave": true,Format on save
  "emmet.showExpandedAbbreviation": "never",
  "js/ts.tsdk.path": "node_modules/typescript/lib",The project’s TypeScript
  "js/ts.tsdk.promptToUseWorkspaceVersion": true,
  "[astro]": {
    "editor.defaultFormatter": "astro-build.astro-vscode"
  },
  "[css]": {
    "editor.defaultFormatter": "oxc.oxc-vscode"
  },
  "[graphql]": {
    "editor.defaultFormatter": "oxc.oxc-vscode"
  },
  "[handlebars]": {
    "editor.defaultFormatter": "oxc.oxc-vscode"
  },
  "[html]": {
    "editor.defaultFormatter": "oxc.oxc-vscode"
  },
  "[javascript]": {
    "editor.defaultFormatter": "oxc.oxc-vscode"
  },
  "[javascriptreact]": {
    "editor.defaultFormatter": "oxc.oxc-vscode"
  },
  "[json]": {
    "editor.defaultFormatter": "oxc.oxc-vscode"
  },
  "[jsonc]": {
    "editor.defaultFormatter": "oxc.oxc-vscode"
  },
  "[less]": {
    "editor.defaultFormatter": "oxc.oxc-vscode"
  },
  "[markdown]": {
    "editor.defaultFormatter": "oxc.oxc-vscode"
  },
  "[scss]": {
    "editor.defaultFormatter": "oxc.oxc-vscode"
  },
  "[typescript]": {Oxfmt formats it
    "editor.defaultFormatter": "oxc.oxc-vscode"
  },
  "[typescriptreact]": {
    "editor.defaultFormatter": "oxc.oxc-vscode"
  },
  "[vue-html]": {
    "editor.defaultFormatter": "oxc.oxc-vscode"
  },
  "[vue]": {
    "editor.defaultFormatter": "oxc.oxc-vscode"
  },
  "[yaml]": {
    "editor.defaultFormatter": "oxc.oxc-vscode"
  },
  "editor.codeActionsOnSave": {
    "source.fixAll.oxc": "explicit"Oxlint’s safe fixes
  },
  "typescript.enablePromptUseWorkspaceTsdk": true,
  "typescript.tsdk": "node_modules/typescript/lib"
}

Oxlint + Oxfmt

What init does in Antigravity IDE

1Writes .vscode/settings.jsonA new file, or merged into yours setting by setting, with your comments and other settings kept.
2Installs oxc.oxc-vscodeWith antigravity-ide --install-extension, when it creates the settings file.

Then, in Antigravity IDE

3If init couldn’t run antigravity-ide, install oxc.oxc-vscode from the Extensions view, or biomejs.biome if you picked Biome. Antigravity IDE searches Open VSX.
4Save a TypeScript file: Oxfmt formats it and Oxlint’s safe fixes apply.

Three toolchains, one settings.json

init writes the settings for the toolchain you pick, so Antigravity IDE formats with the same tool as ultracite fix and applies its fixes when you save.

Oxlint + OxfmtDefault
Extension
oxc.oxc-vscode
Formats with
oxc.oxc-vscode
On save
source.fixAll.oxc
--linter oxlint
Biome
Extension
biomejs.biome
Formats with
biomejs.biome
On save
source.fixAll.biomesource.organizeImports.biome
--linter biome
ESLint + Prettier + Stylelint
Extensions
dbaeumer.vscode-eslintesbenp.prettier-vscode
Formats with
esbenp.prettier-vscode
On save
source.fixAll.eslintsource.organizeImports
--linter eslint

Open VSX extensions and the agent’s reach

Antigravity IDE takes the same settings file as VS Code but gets its extensions from Open VSX. How far its agent can reach into .vscode and the terminal depends on your security settings.

Extensions: From Open VSX by default (the antigravity.marketplaceExtensionGalleryServiceURL setting), not the Visual Studio Marketplace. oxc.oxc-vscode, biomejs.biome, dbaeumer.vscode-eslint and esbenp.prettier-vscode are all there.
Code OSS 1.107: Antigravity IDE 2.5.5 is built on Code OSS 1.107, which predates js/ts.tsdk.path, so for Antigravity init also writes typescript.tsdk.
Moving from 1.0: Since 2.0.3, the IDE can import settings, extensions and keybindings from Antigravity 1.0, the app before the split.
Strict mode: Since 2.1.1, strict mode asks before the agent touches .vscode or .cache. It also makes every terminal command ask, ignores the allowlist and respects .gitignore.
Terminal commands: Request Review asks before any command that isn’t on your allowlist; Always Proceed runs everything that isn’t on your denylist.
File access: By default the agent reaches only your project folders and ~/.gemini/antigravity-ide/, where it keeps artifacts and configuration.

Rules folder by folder, lint errors by ID

Antigravity IDE’s agent combines every rule file it finds instead of picking one, and loads the AGENTS.md in each folder between a file it touches and the workspace root. Its edit tools take a TargetLintErrorIds argument, so an edit can target specific errors your linter reports.

Where the agent looks for instructions

1~/.gemini/AGENTS.md, ~/.gemini/GEMINI.mdGlobal rules for every project: no frontmatter, always on. Modular global rules go in ~/.gemini/config/rules/.
2AGENTS.mdUltraciteAt the workspace root, where init writes Ultracite’s rules. Always on for its folder; a GEMINI.md beside it loads too.
3.agents/rules/*.mdModular rules. Each needs a trigger in its frontmatter (always_on, model_decision, glob or manual), or Antigravity drops it silently.
4src/**/AGENTS.mdLoaded when the agent reads or edits a file below that folder. The more specific folder wins when rules conflict.
5.agents/skills/Workspace skills, where init installs the Ultracite skill. The agent sees each skill’s name and description and reads the rest when it’s relevant.

01The agent edits a file with write_to_file, replace_file_content or multi_replace_file_content.
02Your Oxc, Biome or ESLint extension lints the change in the editor, as it does for your own edits.
03The agent can fix them in place, aiming at specific ones with TargetLintErrorIds, or run npx ultracite check through run_command.
04No Ultracite hook runs. .agents/hooks.json supports PostToolUse, but its documented output is an empty object, so a hook can’t send results back.

Agent pageUltracite for Antigravity CLI

Worth knowing about Antigravity IDE

Antigravity 2.0 is a different app
In May 2026 the original Antigravity split in two. Antigravity 2.0 became a standalone app for running agents, replacing the Agent Manager, and Antigravity IDE kept the editor. 2.0 has an Open IDE button that opens the current project in the IDE; --editors antigravity configures the IDE.
Global skills live in different places
Workspace rules, .agents/skills/ and .agents/hooks.json work the same in the IDE, Antigravity 2.0 and Antigravity CLI. Global skills don’t: the IDE reads ~/.gemini/config/skills/, while the CLI reads ~/.gemini/antigravity-cli/skills/. Keep the Ultracite skill in the workspace.
Rules have a size budget
Antigravity cuts any rule file past 24,000 bytes, and global and always_on rules, AGENTS.md included, share a 20,000-token budget. Past it, the largest files become pointers the agent reads on demand. Ultracite’s rules are about 5 KB.

Antigravity IDE questions, answered

Does Ultracite work with Antigravity IDE?: Yes. npx ultracite init --editors antigravity writes .vscode/settings.json for Oxlint and Oxfmt, Biome, or ESLint and Prettier. It installs the matching extension from Open VSX with the IDE’s antigravity-ide command.
Is Antigravity IDE the same as Antigravity 2.0?: No. Since May 2026, Antigravity 2.0 is a standalone app for running agents that works independently of an IDE, and Antigravity IDE is the editor, installed separately. Ultracite’s antigravity editor setup is for the IDE.
Does Antigravity IDE read AGENTS.md?: Yes, alongside GEMINI.md, since 1.20.5. It loads AGENTS.md at the workspace root and in each folder between a file the agent touches and the root, plus ~/.gemini/AGENTS.md for every project.
Why didn’t the Biome extension install in Antigravity?: init installs it with antigravity-ide --install-extension only when it creates .vscode/settings.json, and only if antigravity-ide is on your PATH. Otherwise, install biomejs.biome from the Extensions view: Antigravity searches Open VSX, where Biome publishes it.
Does Antigravity’s agent see Oxlint errors?: Its edit tools take a TargetLintErrorIds argument for fixing specific lint errors, so it can work through the ones your Oxc extension reports. For a full report, it can run npx ultracite check in the terminal.
Where does Antigravity IDE load skills from?: From .agents/skills/ in the workspace, where init installs the Ultracite skill, and from ~/.gemini/config/skills/ for every project. The older ~/.gemini/antigravity/skills/ still works.

Sources

Keep going

Ship less slop

One command sets up your linter, formatter, editor and agents. Works with Oxlint, Biome and ESLint.