Google's Antigravity is an AI coding IDE that uses a .agent/ directory convention for configuration. ECC provides first-class support for Antigravity through its selective install system.
# Install ECC with Antigravity target
./install.sh --target antigravity typescript
# Or with multiple language modules
./install.sh --target antigravity typescript python goThis installs ECC components into your project's .agent/ directory, ready for Antigravity to pick up.
ECC remaps its component structure to match Antigravity's expected layout:
| ECC Source | Antigravity Destination | What It Contains |
|---|---|---|
rules/ |
.agent/rules/ |
Language rules and coding standards (flattened) |
commands/ |
.agent/workflows/ |
Slash commands become Antigravity workflows |
agents/ |
.agent/skills/ |
Agent definitions become Antigravity skills |
Note on
.agents/vs.agent/vsagents/: The installer only handles three source paths explicitly:rules→.agent/rules/,commands→.agent/workflows/, andagents(no dot prefix) →.agent/skills/. The dot-prefixed.agents/directory in the ECC repo is a static layout for Codex/Antigravity skill definitions andopenai.yamlconfigs — it is not directly mapped by the installer. Any.agents/path falls through to the default scaffold operation. If you want.agents/skills/content available in the Antigravity runtime, you must manually copy it to.agent/skills/.
- Rules are flattened: Claude Code nests rules under subdirectories (
rules/common/,rules/typescript/). Antigravity expects a flatrules/directory — the installer handles this automatically. - Commands become workflows: ECC's
/commandfiles land in.agent/workflows/, which is Antigravity's equivalent of slash commands. - Agents become skills: ECC agent definitions map to
.agent/skills/, where Antigravity looks for skill configurations.
your-project/
├── .agent/
│ ├── rules/
│ │ ├── coding-standards.md
│ │ ├── testing.md
│ │ ├── security.md
│ │ └── typescript.md # language-specific rules
│ ├── workflows/
│ │ ├── plan.md
│ │ ├── code-review.md
│ │ ├── tdd.md
│ │ └── ...
│ ├── skills/
│ │ ├── planner.md
│ │ ├── code-reviewer.md
│ │ ├── tdd-guide.md
│ │ └── ...
│ └── ecc-install-state.json # tracks what ECC installed
Each skill directory under .agents/skills/ contains an agents/openai.yaml file at the path .agents/skills/<skill-name>/agents/openai.yaml that configures the skill for Antigravity:
interface:
display_name: "API Design"
short_description: "REST API design patterns and best practices"
brand_color: "#F97316"
default_prompt: "Design REST API: resources, status codes, pagination"
policy:
allow_implicit_invocation: true| Field | Purpose |
|---|---|
display_name |
Human-readable name shown in Antigravity's UI |
short_description |
Brief description of what the skill does |
brand_color |
Hex color for the skill's visual badge |
default_prompt |
Suggested prompt when the skill is invoked manually |
allow_implicit_invocation |
When true, Antigravity can activate the skill automatically based on context |
node scripts/list-installed.js --target antigravity# First, diagnose what's wrong
node scripts/doctor.js --target antigravity
# Then, restore missing or drifted files
node scripts/repair.js --target antigravitynode scripts/uninstall.js --target antigravityThe installer writes .agent/ecc-install-state.json to track which files ECC owns. This enables safe uninstall and repair — ECC will never touch files it didn't create.
If you're contributing a new skill and want it available on Antigravity:
- Create the skill under
skills/your-skill-name/SKILL.mdas usual - Add an agent definition at
agents/your-skill-name.md— this is the path the installer maps to.agent/skills/at runtime, making your skill available in the Antigravity harness - Add the Antigravity agent config at
.agents/skills/your-skill-name/agents/openai.yaml— this is a static repo layout consumed by Codex for implicit invocation metadata - Mirror the
SKILL.mdcontent to.agents/skills/your-skill-name/SKILL.md— this static copy is used by Codex and serves as a reference for Antigravity - Mention in your PR that you added Antigravity support
Key distinction: The installer deploys
agents/(no dot) →.agent/skills/— this is what makes skills available at runtime. The.agents/(dot-prefixed) directory is a separate static layout for Codexopenai.yamlconfigs and is not auto-deployed by the installer.
See CONTRIBUTING.md for the full contribution guide.
| Feature | Claude Code | Cursor | Codex | Antigravity |
|---|---|---|---|---|
| Install target | claude-home |
cursor-project |
codex-home |
antigravity |
| Config root | ~/.claude/ |
.cursor/ |
~/.codex/ |
.agent/ |
| Scope | User-level | Project-level | User-level | Project-level |
| Rules format | Nested dirs | Flat | Flat | Flat |
| Commands | commands/ |
N/A | N/A | workflows/ |
| Agents/Skills | agents/ |
N/A | N/A | skills/ |
| Install state | ecc-install-state.json |
ecc-install-state.json |
ecc-install-state.json |
ecc-install-state.json |
- Verify the
.agent/directory exists in your project root (not home directory) - Check that
ecc-install-state.jsonwas created — if missing, re-run the installer - Ensure files have
.mdextension and valid frontmatter
- Rules must be in
.agent/rules/, not nested in subdirectories - Run
node scripts/doctor.js --target antigravityto verify the install
- Antigravity looks for workflows in
.agent/workflows/, notcommands/ - If you manually copied ECC commands, rename the directory
- Selective Install Architecture — how the install system works under the hood
- Selective Install Design — design decisions and target adapter contracts
- CONTRIBUTING.md — how to contribute skills, agents, and commands