Antigravity / Gemini CLI configuration guide: instruction files, MCP, permissions

Google moved individual Gemini CLI users to Antigravity CLI on June 18, 2026. Antigravity loads AGENTS.md or GEMINI.md (plus .agents/rules/*.md) per directory and global rules from ~/.gemini/AGENTS.md or ~/.gemini/GEMINI.md. Its MCP servers live in ~/.gemini/config/mcp_config.json or .agents/mcp_config.json, and permissions are Deny / Ask / Allow lists on top of a Default, Request Review or Turbo preset. Gemini CLI uses ~/.gemini/settings.json / .gemini/settings.json (mcpServers, context.fileName) plus policy TOML files, and reads only GEMINI.md unless you set context.fileName. Sign in with a Google account (Google AI Pro/Ultra included) or use a Gemini API key.

Antigravity / Gemini CLI at a glance

Exact file paths

Using a shared AGENTS.md with Antigravity / Gemini CLI

Antigravity: native. Gemini CLI: set context.fileName to ["AGENTS.md", "GEMINI.md"] in .gemini/settings.json (or symlink GEMINI.md). See one AGENTS.md for every agent, or generate one with the AGENTS.md generator.

Copy-paste examples

Make Gemini CLI read AGENTS.md

File: .gemini/settings.json

{
  "context": {
    "fileName": ["AGENTS.md", "GEMINI.md"]
  }
}

Antigravity workspace MCP server

File: .agents/mcp_config.json

{
  "mcpServers": {
    "context7": {
      "command": "npx",
      "args": ["-y", "@upstash/context7-mcp"]
    }
  }
}

Gemini CLI policy: deny rm -rf

File: ~/.gemini/policies/safety.toml

[[rule]]
toolName = "run_shell_command"
commandPrefix = "rm -rf"
decision = "deny"
priority = 100

[[rule]]
toolName = "run_shell_command"
commandPrefix = "git push"
decision = "ask_user"
priority = 100

Safe permissions preset

Safe Antigravity permissions (Deny / Ask lists)

File: Settings → Permissions

Preset: Default   (terminal sandbox on, workspace + temp dirs only, no network)

Deny:
  command(rm -rf)
  command(sudo)
  command(git push --force)
  command(git push -f)
  command(git reset --hard)
  command(terraform destroy)
  read_file(~/.ssh)
  read_file(~/.aws)
  write_file(.env)

Ask:
  command(git push)
  command(kubectl)
  command(psql)
  command(mysql)

Antigravity evaluates Deny > Ask > Allow and matches commands by literal token prefix (or regex: per token), so a SQL statement inside psql -c can't be matched; put database clients in Ask instead. Turbo disables the sandbox and allows everything. The docs don't name the file these lists are stored in, so set them in Settings.

Gotchas

• Gemini CLI stopped serving free, Google AI Pro and Ultra individual users on June 18, 2026; they were moved to Antigravity CLI. API-key, Vertex and enterprise users can still run Gemini CLI.
• Gemini CLI ignores AGENTS.md unless context.fileName lists it; Antigravity reads it natively.
• Antigravity only scans the immediate .md children of .agents/rules/.
• Antigravity's Turbo preset turns the sandbox off and allows commands without prompting.
• Command substitution such as $(...) or backticks can hide a command behind a harmless prefix; Antigravity treats those constructs specially, but keep destructive tools in Deny.

FAQ

Sources

Checked against these official pages on 2026-10-12. Cells marked "Not documented" mean we could not find the behaviour in these docs; it may still exist.

• Antigravity rules
• Antigravity MCP
• Antigravity skills
• Antigravity permissions
• Antigravity terminal sandbox
• Antigravity hooks
• Antigravity CLI install & auth
• Gemini CLI to Antigravity migration
• Gemini CLI GEMINI.md
• Gemini CLI configuration
• Gemini CLI policy engine
• Gemini CLI sandbox