Gemini CLI Extension

The Constellation extension for Gemini CLI supercharges your AI-assisted development workflow with deep codebase understanding. It provides specialized skills, custom slash commands, and session hooks that leverage Constellation's code intelligence platform.

Source: github.com/ShiftinBits/constellation-gemini

Overview

Feature	Description
2 Skills	Procedural guidance for troubleshooting and impact analysis
6 Commands	Custom slash commands for connectivity checks, architecture overview, and more
4 Hooks	Intelligent context injection across sessions, sub-agents, and tool selection

Installation

Prerequisites

• Gemini CLI installed
• A Constellation account
• Constellation CLI utility installed
• A project previously indexed in Constellation

Quick Start

1. Install the extension:

   _{Enter the following in your terminal:}

   gemini extensions install https://github.com/ShiftinBits/constellation-gemini

2. Configure authentication:

   _{Enter the following in your terminal:}

   npx @constellationdev/cli auth

3. Verify the connection:

   _{Enter the following in Gemini CLI:}

   /constellation:status

Uninstall

_{Enter the following in your terminal:}

gemini extensions uninstall constellation

Commands

The extension adds several slash commands to Gemini CLI for quick access to Constellation's features.

Status

/constellation:status

Check API connectivity and authentication status.

> /constellation:status

Status: Connected
- Authentication valid, project access confirmed
- Note: Use /constellation:diagnose to check indexing status

Diagnose

/constellation:diagnose

Perform a full health check of the Constellation connection, authentication, and project indexing.

Architecture

/constellation:architecture

Get a high-level overview of the codebase architecture, including language distribution and key modules.

Dependencies

/constellation:deps <file-path> [--reverse]

Analyze dependencies for a specific file. Use the --reverse flag to see what depends on the file.

Impact Analysis

/constellation:impact <symbol-name>

Analyze the impact of changing a specific symbol to understand the potential "blast radius" of a change.

Unused Code

/constellation:unused

Find dead code that is exported but never imported or used anywhere in the codebase.

Skills

Skills are procedural guidance that Gemini CLI activates based on conversation keywords.

Constellation Troubleshooting

Diagnostic procedures for Constellation-specific errors, indexing problems, MCP server issues, and connectivity failures. Includes a quick error code reference (AUTH_ERROR, PROJECT_NOT_INDEXED, SYMBOL_NOT_FOUND, FILE_NOT_FOUND, API_UNREACHABLE).

Impact Analysis

Pre-change risk assessment guidance. Triggered by questions like "impact of changing X", "what would break if I modify X", "blast radius", "risk of renaming X", or "safe to delete X". Walks through symbol lookup, dependent enumeration, test coverage, and recommendation reporting.

Hooks

Hooks transparently steer Gemini toward code_intel for structural code questions. All hooks are gated on CONSTELLATION_ACCESS_KEY being set (prefix ak:) and emit context only — they never block execution.

Event	Matcher	Behavior
SessionStart	.*	Establishes code_intel as the primary tool for code understanding when a session starts
BeforeAgent	.*	Injects the same awareness into spawned sub-agents (built-ins don't inherit GEMINI.md)
BeforeTool	grep_search|glob	Reminds Gemini to prefer code_intel for structural queries before falling back to text search
BeforeTool	run_shell_command	Inspects tool_input.command and emits the same reminder when grep, rg, glob, awk, or findstr appears