Add documentation and migration commands for Antigravity CLI

[DavidAPierce]

Summary

This Pull Request introduces platform-aware support for retrieving and displaying Antigravity CLI installation and migration details. It provides a seamless transition path for users migrating from Gemini CLI, allowing them to fetch exact setup instructions from both interactive banners and the built-in /help command, and introduces a dedicated antigravity-support skill.

---

Details

1. Platform-Specific Utility (antigravityUtils.ts)

• Encapsulates OS detection to return customized installation scripts:
  • macOS / Linux: Sourced via standard curl -fsSL https://antigravity.google/cli/install.sh | bash.
  • Windows (PowerShell): Generated as irm https://antigravity.google/cli/install.ps1 | iex (active if PSModulePath exists in environment).
  • Windows (Command Prompt): Falls back to a CMD curl-and-run sequence.
  • Unsupported (e.g. FreeBSD): Gracefully returns null, prompting a fallback link to the web documentation.

2. Interactive /help Command Integration

• Intercepts requests matching antigravity and install/migrate to print the exact, copy-pasteable installation script matching the user's current environment.

3. Dynamic Banner Injection

• Intercepts promotional banners that mention "Antigravity" and appends the customized installation instruction to the footer, styled using chalk.bold.

4. Dedicated Built-in Skill (antigravity-support)

• Registers antigravity-support built-in skill featuring in-depth documentation regarding installation, setup trust verification, styling configuration, and transition flows from Gemini CLI.

5. Tests Added

• antigravityUtils.test.ts: Verifies precise command return values for all operating systems and environment variations.
• helpCommand.test.ts: Verifies intercept-handling, correct text formats, and platform-fallback behavior.
• useBanner.test.ts: Verifies dynamic banner text modifications across platforms.
• skillLoader.test.ts: Validates successful loading and verification of the new built-in skill structure.

---

Related Issues

Related to the migration of users to the Antigravity CLI.

---

How to Validate

1. Automated Tests

Run unit tests across the CLI and Core workspaces to ensure all assertions pass successfully:

npm test -w @google/gemini-cli -- src/ui/utils/antigravityUtils.test.ts
npm test -w @google/gemini-cli -- src/ui/commands/helpCommand.test.ts
npm test -w @google/gemini-cli -- src/ui/hooks/useBanner.test.ts
npm test -w @google/gemini-cli-core -- src/skills/skillLoader.test.ts

2. Interactive Walkthrough

1. Build the packages:

   npm run build

2. Run the interactive development environment:

   npm run start

3. Type:

   /help install antigravity
   

   Verify that the output displays the correct command for your operating system.
4. Query for something related to Antigravity or how to install it and or migrate to it, and verify if the response makes use of the added skill and the output is actionable.

---

Pre-Merge Checklist

• Updated relevant documentation and README (if needed)
• Added/updated tests (if needed)
• Noted breaking changes (if any)
• Validated on required platforms/methods:
  • MacOS
    • npm run
  • Linux
    • npm run
  • Windows
    • npm run (validated via robust environment stubbing tests)

[github-actions]

📊 PR Size: size/L

• Lines changed: 406
• Additions: +395
• Deletions: -11
• Files changed: 8

[gemini-code-assist]

Summary of Changes

Hello, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request streamlines the onboarding experience for the Antigravity CLI by integrating platform-specific installation guidance directly into the user interface. By leveraging existing help commands, promotional banners, and a new support skill, users can easily discover and execute the correct setup steps for their specific environment, facilitating a smoother transition from previous tools.

Highlights

• Platform-Aware Installation: Introduced a utility to detect the user's operating system and provide the correct installation command for the Antigravity CLI.
• Interactive Help Integration: Updated the /help command to intercept queries related to Antigravity installation and migration, providing actionable instructions.
• Dynamic Banner Injection: Enhanced promotional banners to automatically append installation instructions when Antigravity is mentioned.
• New Support Skill: Added a dedicated 'antigravity-support' skill containing comprehensive documentation for setup and migration.

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[gemini-code-assist]

Code Review

This pull request adds platform-specific installation and migration support for the Antigravity CLI by updating the help command, banner hooks, and adding a new built-in skill with comprehensive documentation and tests. The review feedback highlights a critical issue on Windows where PSModulePath is always set, rendering the Command Prompt fallback unreachable. Additionally, the reviewer recommends downloading the Windows installer script to the temporary directory (%TEMP%) instead of the current working directory to prevent file overwrites, and suggests extracting duplicate installation command strings into a shared constant.

[github-actions]

Size Change: +2.03 kB (+0.01%)

Total Size: 33.9 MB

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[galdawave]

Code Review: PR 27765

Intent Summary: This PR introduces platform-aware installation commands for the Antigravity CLI to assist migrating users. It integrates these instructions into the /help command, appends them to relevant UI banners, and registers a new antigravity-support built-in skill.

🚨 Critical Concerns (P0/P1)

Action required before merging.

• packages/cli/src/ui/hooks/useBanner.ts:53: Hardcoding product-specific substring checks (activeText.includes('Antigravity')) inside a generic UI presentation hook violates separation of concerns. If a promotional banner requires an action or footer, the BannerData payload should be extended to include this information natively rather than intercepting raw strings in the React layer.

  // Prefer driving this via data from the backend/config:
  if (showBanner && bannerData.footerText) {
    bannerText += `\n \n${bannerData.footerText}`;
  }

🧹 Refactoring & Nits (P2/P3)

Recommended improvements.

• packages/cli/src/ui/commands/helpCommand.ts:18: Similar to the banner issue, intercepting hasAntigravity inside the generic /help command is an architectural smell. While acceptable as a temporary migration hack, this logic should ideally live in a command registry or rely on the agent's routing.
• packages/cli/src/ui/commands/helpCommand.test.ts:32: Directly mutating process.env = { ...originalEnv }; violates the project's testing conventions (as noted in GEMINI.md). Since this PR correctly introduces vi.unstubAllEnvs(), you should remove originalEnv entirely to eliminate the redundant manual caching.
• packages/cli/src/ui/hooks/useBanner.ts:56: Mixing chalk.bold strings with Ink components is an anti-pattern. While Ink can pass through ANSI escape codes, the idiomatic React/Ink approach is to return structured text (e.g., <Text bold>).
• packages/core/src/skills/builtin/antigravity-support/SKILL.md:33: The documentation specifies iwr -useb https://antigravity.google/cli/install.ps1 | iex for PowerShell, but the codebase (antigravityUtils.ts) returns irm ... | iex. Align both to use the same command (preferably irm).

[DavidAPierce]

The hard coded separation check is still needed, as this is a temp banner that needs updating asap without additional backend support. Ack that it would be a better long term solution.

Similar response to the help command interceptor. This behavior was specifically requested and is a temporary hack for migration.

Valid point on chalk.bold, however it is used in different parts of the repo, and works in local testing.

The help command test and the skill updates are good points, and have been updated to be addressed.