[External Plugin]: constellation

[lowdrag84]

Plugin name

constellation

Short description

MCP profile management for GitHub Copilot CLI. Controls which MCP servers are active per task domain through named profiles, reducing token usage by ~50% per turn. Provides 11 tools for profile switching, creation, updates, and a la carte MCP server loading — all at runtime without restarting the session.

GitHub repository

lowdrag84/constellation

Plugin path inside the repository

No response

Immutable ref to review

refs/tags/v1.0.0

Version

1.0.0

License identifier

MIT

Author name

Garrett Curtin

Author URL

https://github.com/lowdrag84

Homepage URL

https://github.com/lowdrag84/constellation

Keywords

mcp
profile-management
token-optimization
copilot-cli
developer-tools
configuration
mcp-servers

Additional notes for reviewers

Constellation is a Copilot CLI extension that addresses a significant token cost problem: each MCP server registers 5-35 tools into the system prompt, costing ~150-300 tokens per tool per turn. With 10+ MCPs loaded, the system prompt consumes 30,000+ tokens per turn — mostly for unused tools.

Measured impact from real-world testing: a full-to-lean profile switch removed ~109 tools across 6 MCPs, saving 16,000-33,000 tokens per turn (480K-990K tokens over a 30-turn session).

The extension uses the public @github/copilot-sdk/extension package (MIT, npm) for tool registration and live MCP toggling via session.rpc.mcp.enable/disable. Zero external dependencies — the SDK is bundled with the CLI runtime.

Currently Windows-only (PowerShell setup script). Mac/Linux support planned.

Submission checklist

• The plugin lives in a public GitHub repository.
• The ref I provided is an immutable release tag or full 40-character commit SHA, not a branch.
• This submission follows this repository's contribution, security, and responsible AI policies.
• This plugin is not already listed in the Awesome Copilot marketplace.

[aaronpowell]

Extensions aren't part of plugins

[lowdrag84]

Thanks for the feedback. To clarify what Constellation is:

It's a .github/extensions extension built with @github/copilot-sdk/extension — the same SDK and discovery mechanism used by hooks. It registers tools and an onSessionStart hook via joinSession(). The extension manages which MCP servers are active through named profiles, reducing system prompt token usage by ~50% per turn.

It installs to .github/extensions/constellation/extension.mjs (project-level) or the user extensions directory, and works in both Copilot CLI and the coding agent since they share the same runtime.

Given that it's an extension using the SDK (not a plugin in the marketplace sense), where would this belong in Awesome Copilot?

@aaronpowell