[fnzko]

What does this PR do?

Part of #277.
Depends on #332 (until it merges, only the last commit is new here).

An author who wants to hand their plugin to an agent directly, without Symposium, has no way to get the directory agents load. Symposium builds that directory only for plugins a user enables with use --global.

Now cargo agents plugin compile <dir> --out <out> validates a plugin or skill directory and writes <out>/<name>/ with plugin.json, the same manifest in .claude-plugin/plugin.json, and the skills. It then prints how to load the result in each agent, for example claude --plugin-dir. Running it again replaces its own output. A directory it did not write is left alone, and nothing else under <out> is touched.

Verified with integration tests, and in Claude Code and Copilot CLI with --plugin-dir: each agent loads the plugin and its skill, and claude plugin validate passes.

Take into account:

• Only skills are compiled. Hooks, MCP servers and subcommands are left out with a warning.
• Conflicts with fix(plugins): validate a crate folder as its users get it #370 and feat(plugin-tooling): validate, try and import plugins as an author #373 in the authoring guide and the plugin reference. Whichever merges second adds plugin compile to the author tools list.

Disclosure questions

AI disclosure.

• The AI tool authored large parts of the code

[fnzko]

Closing for now: it builds on #332, which waits on the plugin delivery decision.