Add pkgx manifest for just-mcp

[elasticdotventures]

Summary

• add the pkgx pantry manifest so pkgx can install the just-mcp binary per host/arch
• document the release artifacts the manifest expects so CI upload remains compatible

Testing

• not run (packaging change only)

[Copilot]

Pull request overview

This PR adds a pkgx pantry manifest for the just-mcp project, enabling automated installation of precompiled binaries across multiple platforms. The manifest downloads platform-specific release artifacts and installs them to the appropriate location, with accompanying documentation on release requirements.

• Implements a pkgx package manifest with cross-platform binary downloads for Linux, macOS, and Windows
• Documents release artifact requirements for CI/CD compatibility
• Follows the pattern of similar cross-platform packages in the pantry

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
projects/github.com/promptexecution/just-mcp/package.yml	Defines the package manifest with platform detection, binary download via curl, and installation logic for x86_64/aarch64 across Linux/macOS/Windows
projects/github.com/promptexecution/just-mcp/README.md	Documents the package requirements and expected release artifact naming conventions for CI/CD systems

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[jhheider]

thanks for this, @elasticdotventures ! i love just, and this is a great idea.

[elasticdotventures]

thanks for this, @elasticdotventures ! i love just, and this is a great idea.

Thanks @jhheider -- thats great, I really love pkgx.

As a rust dev it's certainly the easiest way to publish mcp servers.
I've got ~10 different MCP servers I'll be adding to the pantry in the coming weeks.

Are you aware of a good URL agent recipe for pkgx -- if not -- would you be open to having an "official" pkgx agent?
i.e. a claude-code recipe most companies have started adding that a "marketplace" repo under the org.
it would explain the pantry format, checklist for pkgx, etc. info here:

https://code.claude.com/docs/en/plugin-marketplaces

the convention i've seen elsewhere is:
pkgxdev/agents or pkgxdev/claude-code
(*i like agents, but some repos have different versions for different tools)

so the syntax would be something like:

/plugin marketplace add pkgxdev/agents
/plugin install pkgx-package-maintainer@pkgxdev

then a user can just add pkgx as a marketplace and then use the pkgx-package-maintainer
the same marketplace might also have a pkgx-installer, or .. ?? but at least having a tool that can go from zero to pkgx
Let me know if you're open (I'm happy to build and test on my stuff to prove it works, I am testing prompt that I think does a good job but happy to incorporate feedback if you want to critique my/claudes pkgx submissions!)

[jhheider]

Would love to see it. If you develop it, you should get the credit. We do have pkgxdev/mcp, so you should be able to incorporate that.