Bug: Project-scoped plugins incorrectly detected as installed globally

[ianaswanson]

Summary

When a plugin is installed with --scope project, other projects incorrectly show the plugin as "(installed)" in the Marketplaces view and refuse to install it, even though it's not active in those projects.

Claude Code Version: 2.0.70

Steps to Reproduce

1. Create a local plugin marketplace with a plugin (e.g., my-plugin@my-marketplace)

2. In Project A, install the plugin with project scope:

   /plugin marketplace add /path/to/marketplace
   /plugin install my-plugin@my-marketplace --scope project
   

3. Verify it works in Project A:

   • /plugin → Installed tab shows the plugin ✓

4. Open Claude Code in Project B (different directory)

5. Run /plugin and navigate to Marketplaces tab

   Expected: Plugin shows as available to install (not installed in this project)

   Actual: Plugin shows "(installed)" with a checkmark

6. Try to install the plugin for Project B:

   /plugin install my-plugin@my-marketplace --scope project
   

   Expected: Plugin installs for Project B

   Actual: Installation fails/skips because Claude Code thinks it's already installed

7. Check Installed tab in Project B

   Result: Plugin does NOT appear in Installed tab (correctly filtered by projectPath)

Root Cause Analysis

The bug is an inconsistency in how projectPath is checked across different plugin operations:

Operation	Checks projectPath?	Behavior
Marketplaces "(installed)" indicator	❌ No	Shows installed globally
Install command	❌ No	Refuses if exists globally
Installed tab listing	✓ Yes	Correctly filters by project

The plugin registry at ~/.claude/plugins/installed_plugins.json correctly stores projectPath for project-scoped installs, but the Marketplaces view and install command only check if the plugin key exists in the registry, not whether it's installed for the current project.

Workaround

Manually add the new project to ~/.claude/plugins/installed_plugins.json and create .claude/settings.json in the target project with enabledPlugins reference.

Impact

This bug prevents using the same local plugin across multiple projects with project-scoped isolation, which is a core use case for local plugin marketplaces in monorepos or multi-project setups.

[ejfn]

+1
same here.

[MarkMolina]

Thanks for reporting, was about to do this.

+1

[tettuan]

I've encountered a related issue and documented it in #15524.

The root cause appears to be that /plugin install doesn't update the project-level <project>/.claude/settings.json with enabledPlugins. Even when installed_plugins.json has the correct entry with projectPath, the plugin won't appear in the "Installed" tab until enabledPlugins is manually added to the project's settings.json.

Required files for project-scoped plugins to work:

1. ~/.claude/plugins/installed_plugins.json with correct projectPath
2. <project>/.claude/settings.json with enabledPlugins: { "plugin@marketplace": true }

Workaround: Manually create both files.

[kuanwen-liu]

---

I can confirm experiencing this exact bug. Here's my detailed experience:

Summary

The /plugin install command reports "already installed" for frontend-design@claude-plugins-official, but the plugin doesn't appear in /plugin list and is not actually installed anywhere in the system.

What I Tried

Attempt 1: Clear the plugin cache
rm -rf ~/.claude/plugins/cache
/plugin install frontend-design@claude-plugins-official
Result: Still says "already installed"

Attempt 2: Clear the installation registry

Edited ~/.claude/plugins/installed_plugins.json to:

{
"version": 2,
"plugins": {}
}
Then tried installing again.
Result: Still says "already installed"

Attempt 3: Clear both cache AND registry
rm -rf ~/.claude/plugins/cache/claude-plugins-official/frontend-design

Verified installed_plugins.json was empty

/plugin install frontend-design@claude-plugins-official
Result: Still says "already installed"

Evidence of Bug

1. Installation registry is empty:
   cat ~/.claude/plugins/installed_plugins.json

{"version": 2, "plugins": {}}

2. Cache directory is empty:
   ls ~/.claude/plugins/cache/claude-plugins-official/

(empty - only . and ..)

3. No plugin.json files in cache:
   find ~/.claude/plugins/cache -type f -name "plugin.json"

(no results)

4. UI shows conflicting state:
   - Installed tab: "No plugins installed" ✓ (correct)
   - Marketplaces tab: Shows "(installed)" ✗ (incorrect)
   - Install command: "already installed" ✗ (incorrect)

Root Cause Hypothesis

The plugin system appears to check if the plugin exists in the marketplace catalog directory (~/.claude/plugins/marketplaces/claude-plugins-official/plugins/frontend-design/) rather than checking the actual installation state in:

• ~/.claude/plugins/cache/
• ~/.claude/plugins/installed_plugins.json

This directory exists because I have the marketplace installed, but it's just the catalog/source, not an actual plugin installation.

Environment

• OS: macOS (Darwin 22.4.0)
• Date: December 27, 2025

Impact

Cannot install this plugin at all, even after completely clearing all plugin state. The bug persists across Claude Code sessions.

Workaround Used

Created a project-level skill in .claude/skills/frontend-design/ instead of using the plugin.

---

[thienanblog]

The issue remains unresolved. I'm also experiencing this problem with my repository: https://github.com/thienanblog/awesome-ai-agent-skills , which prevents users from installing any plugins if they are already installed locally in another repository, but it still shows as installed.

[diegomarino]

Additional edge case: orphaned project paths

The same behavior occurs when the original projectPath no longer exists (deleted directory):

Operation	Checks projectPath exists?	Behavior
Marketplaces "(installed)"	❌ No	Shows installed for a non-existent path
Install command	❌ No	Refuses to install in new project

Steps to reproduce:

1. Install plugin with --scope project in Project A
2. Delete Project A directory
3. Open Claude Code in Project B → plugin shows "(installed)", cannot reinstall

Workaround: Manually remove the orphaned entry from ~/.claude/plugins/installed_plugins.json