Unclear behavior when same plugin loaded via marketplace and --plugin-dir

Summary

When a plugin is installed from a marketplace and loaded locally via --plugin-dir, it's unclear whether Claude Code deduplicates them or loads both copies simultaneously.

Context

From our internal repo:

If you still have the marketplace version of the same plugin installed, both copies will be active at once. This can cause confusing behavior (duplicate skills, commands, etc.).

We observed this while documenting local plugin development workflows. A teammate questioned whether this is actually the case, or if Claude Code handles deduplication.

Expected behavior

One of:

1. Claude Code deduplicates plugins by name, preferring --plugin-dir (local) over marketplace — and this is documented
2. Claude Code warns the user when a duplicate plugin is detected
3. Claude Code loads both copies (current suspected behavior) — if intentional, this should be documented

Steps to reproduce

1. Install a plugin from a marketplace: /plugin marketplace add <marketplace-repo>
2. Clone the same marketplace repo locally
3. Run claude --plugin-dir plugins/<same-plugin>
4. Observe whether skills, hooks, and commands from the plugin appear once or twice

Environment

• Claude Code CLI (latest)
• macOS