feat(cli): add support for the ${extensionPath} variable in extension TOML commands

[moisgobg]

Summary

This PR enables portability for custom commands defined within extensions by introducing a new ${extensionPath} variable, and immediately applies this feature to fix a critical path resolution bug in the built-in Conductor extension.

Previously, extension commands had no reliable way to reference files or assets bundled within their own directory (e.g., the templates folder in Conductor) without hardcoding absolute paths or relying on fragile assumptions about where the extension was installed.

By injecting the absolute extension path dynamically at load time, extensions can now reliably bundle and access their own resources regardless of whether they are user-installed or built-in to the CLI bundle.

Details

Commit 1: Core Framework Support

• Updates FileCommandLoader.ts to automatically detect and replace ${extensionPath} instances in parsed TOML prompt strings.
• The substitution is only applied if the command belongs to an active extension (protecting standard User and Workspace commands from unexpected behavior).
• Includes unit tests to verify the substitution logic.

Commit 2: Conductor Fix

• Migrates the built-in Conductor setup.toml command away from hardcoded paths by replacing them with ${extensionPath}/templates/... to copy code style guides and the workflow template.
• This directly unblocks the integration of Conductor as a built-in extension, as the bundled extension lives in a different installation directory, causing the previous hardcoded paths to fail.

How to Validate

1. Validate the Core Feature (Unit Tests)

Run the updated unit tests for the FileCommandLoader to ensure the injection logic is sound:

npm run test --workspace @google/gemini-cli -- src/services/FileCommandLoader.test.ts

2. Validate the Conductor Fix (Manual)

1. Ensure you have the feat/extension-path-injection branch checked out.
2. Run the CLI in a completely empty, temporary directory:

mkdir -p /tmp/conductor-test && cd /tmp/conductor-test
gemini

3. Run /conductor:setup.
4. Complete the interactive prompts. When you get to the code style guides step, you can either pick the recommended ones or choose specific guides.
5. The CLI will present a shell confirmation prompt (Allow execution of: cp ...).
6. Verify: Look closely at the cp command in the confirmation dialog. The source path should now correctly point to the absolute path of your current extension build directory rather than the hardcoded ~/.gemini/extensions/conductor/... path.

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
    • npx
    • Docker
    • Podman
    • Seatbelt
  • Windows
    • npm run
    • npx
    • Docker
  • Linux
    • npm run
    • npx
    • Docker

Fixes #22722

[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 significantly enhances the CLI's extension system by enabling extensions to reliably reference their internal resources, regardless of their installation location. It introduces a new ${extensionPath} variable that dynamically resolves to an extension's root directory, ensuring that custom commands can access bundled files without fragile, hardcoded paths. This change directly addresses and fixes a critical path resolution issue within the Conductor extension, making it fully portable when integrated as a built-in component.

Highlights

• Extension Path Variable Support: Introduced the ${extensionPath} variable, allowing extension TOML commands to dynamically reference their own installation directory for improved portability.
• Core Framework Implementation: Implemented logic within FileCommandLoader.ts to detect and replace ${extensionPath} instances in prompt strings, ensuring this functionality is applied only to active extension commands.
• Conductor Extension Fix: Resolved a critical path resolution bug in the built-in Conductor extension by updating its setup.toml command to utilize the new ${extensionPath} variable, replacing previously hardcoded paths.

Changelog

• packages/cli/src/services/FileCommandLoader.test.ts
  • Added a new unit test to verify the correct injection of the ${extensionPath} variable into extension command prompts.
• packages/cli/src/services/FileCommandLoader.ts
  • Extended the CommandDirectory interface to include an optional extensionPath property.
  • Modified the loadCommands method to pass the extensionPath when processing extension command directories.
  • Implemented a string replacement mechanism within loadCommandFile to substitute ${extensionPath} placeholders in command prompt strings with the actual extension path for extension-specific commands.
• packages/core/src/extensions/builtin/conductor/commands/conductor/setup.toml
  • Updated the setup.toml command to replace hardcoded paths (e.g., ~/.gemini/extensions/conductor/templates/) with the new ${extensionPath}/templates/ variable for listing and copying code style guides and workflow templates.

Activity

• The pull request was created by moisgobg.

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[gemini-code-assist]

Code Review

This pull request introduces a valuable ${extensionPath} variable for extension commands, which significantly improves their portability. The overall implementation is solid, and the updates to the Conductor extension and the new unit tests are great additions. However, I've identified one high-severity security issue in the string replacement logic. The current approach can misinterpret special characters (like $) in file paths, potentially leading to incorrect command generation and security risks. I've provided a code suggestion to resolve this by ensuring the path is treated as a literal string during substitution, aligning with best practices for path sanitization.