antigravity

Antigravity (Gemini / agy) — Adapter Specification

Based on the Agent Adapter Template.

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1. Official References

• Plugin docs: https://antigravity.google/docs/cli/plugins
• Note: Antigravity has a convention-based discovery model. There is no rich manifest schema — plugins are discovered by directory structure and file presence.

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2. Projection Output

• Output directory: Plugin root (no subdirectory)
• Manifest file: plugin.json (at plugin root)
• MCP config: mcp_config.json (at plugin root, copied from source .mcp.json)
• Hooks config: hooks.json (at plugin root, translated from canonical format)
• Runner script: .antigravity-plugin/hook-runner.mjs (generated bridge)
• Adapter source: src/adapters/antigravity.ts, src/adapters/antigravity-hooks.ts

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3. Manifest Schema

Required fields: name only.

The projected plugin.json contains only the plugin name. All other metadata is discovered by convention (presence of sibling directories/files).

// Projected plugin.json — minimal by design
{ "name": "my-plugin" }

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4. Supported Components

Component	Supported	Manifest Key	Discovery Mechanism
Skills	✅	—	Auto-scan skills/ dir for sub-dirs with SKILL.md
Agents	✅	—	Auto-scan agents/ dir
Commands	✅	—	Auto-scan commands/ dir
Hooks	✅	—	Root hooks.json file (native schema)
MCP	✅	—	Root mcp_config.json file
Apps	❌	—	Not supported by Antigravity

Key difference: Antigravity does NOT read the manifest for component paths. It discovers components purely by scanning known directory names and file names at the plugin root. The ADG adapter materializes files at these conventional locations.

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5. Skills

• Declared form: No manifest field. Antigravity scans skills/ at the plugin root.
• Strict mode: N/A — always auto-discovers. No explicit skill list in manifest.
• Array encoding: N/A — not declared in manifest.
• Auto-discovery: Scans skills/ for sub-dirs containing SKILL.md. Each sub-dir's SKILL.md YAML frontmatter provides name and description.
• SKILL.md structure: Identical across all agents:

  skills/<name>/
  └── SKILL.md          # Required: YAML frontmatter (name, description) + body