Constellation Agent Plugin

Agent Plugins MCP Server License: AGPL-3.0

Constellation upgrades your AI agent from text search to code understanding. This is the vendor-neutral Agent Plugins package: it works in any client that implements the Agent Plugins specification, bundling the Constellation MCP server with skills that teach the agent when and how to use it.

Feature	Benefit
MCP Server	The `constellation` server exposes the `code_intel` tool for querying your code graph
Contextual Skills	The agent automatically loads relevant knowledge, including proactive impact analysis before risky changes

Features

Skills

The agent activates specialized knowledge based on your questions:

Skill	Triggers When You Ask About...
impact-analysis	Renaming, refactoring, deleting, or moving symbols/files; "what would break if...", "is X safe to remove"
dependency-analysis	"What does X import", "what depends on X", circular dependencies
dead-code	Unused code, orphaned exports, cleanup opportunities
architecture-overview	"Explain the architecture", "how is this project structured"
constellation-status	"Is Constellation working", health checks, indexing status
constellation-troubleshooting	Error codes, connectivity issues, debugging problems

Example Trigger:

You: "Rename AuthService to AuthenticationService"
Agent: "Before renaming, let me analyze the potential impact..."
[impact-analysis skill activates, runs api.impactAnalysis, reports risk + dependents]

Installation

Prerequisites

Constellation Account (see Constellation)
Project indexed in Constellation (constellation index --full)
Access key configured: the MCP server reads CONSTELLATION_ACCESS_KEY from the environment your agent client runs in. Configure it with npx @constellationdev/cli auth or export it directly.

Install

Install this plugin with any client that supports the Agent Plugins specification. Installation steps vary by client; point yours at this repository or a local clone of it.

Looking for a client-specific plugin instead? Constellation also ships native plugins for Claude Code, Codex, Copilot, Cursor, Antigravity, and OpenCode.

Usage Examples

Check Your Setup

> Is Constellation working?

Constellation Health Check
===========================
MCP Server:  OK
API Auth:    OK
Project:     TypeScript project
Index:       1,247 files, 8,932 symbols

All systems operational.

Analyze Before Refactoring

> What's the impact of changing validateUser in src/auth/validator.ts?

Symbol: validateUser (function)
Risk Level: MEDIUM
Files Affected: 12
Direct Dependents: 34
Impacted Test Files: 3

Recommendations:
- Update unit tests in auth.spec.ts
- Check integration with UserController

Find Dead Code

> Find unused functions in this codebase

Found 7 orphaned functions:
├── src/utils/legacy.ts
│   ├── formatLegacyDate
│   └── parseLegacyConfig
├── src/helpers/deprecated.ts
│   └── oldValidation
...

Understand Dependencies

> What does src/services/payment.service.ts depend on?

Dependencies (12):
├── Internal (8)
│   ├── src/models/payment.model.ts
│   ├── src/utils/currency.ts
│   └── ...
└── External (4)
    ├── stripe
    ├── lodash
    └── ...

No circular dependencies detected.

Troubleshooting

Common Issues

Issue	Solution
`AUTH_ERROR`	Ensure `CONSTELLATION_ACCESS_KEY` is set in your client's environment; run `constellation auth` to configure
`PROJECT_NOT_INDEXED`	Run `constellation index --full` in your project
MCP server unavailable	Restart your agent client; verify `npx -y @constellationdev/mcp@latest --version` runs

The constellation-troubleshooting skill includes a full error code reference.

Documentation

Constellation Documentation - Full platform documentation
MCP Server - Underlying MCP server
Agent Plugins Specification - The packaging standard this plugin targets

License

GNU Affero General Public License v3.0 (AGPL-3.0)

See LICENSE file for details.