Plugin installation fails with EPERM error when running from Claude Code session

Problem

When running claude plugins install from within a Claude Code session (via the Bash tool), the installation fails with permission errors:

Error: EPERM: operation not permitted, open '/Users/username/.claude.json'
Error: EPERM: operation not permitted, open '/Users/username/.claude/projects/.../session.jsonl'

Steps to Reproduce

1. Start a Claude Code session (CLI or VSCode extension)
2. Ask Claude to install a plugin via the Bash tool:

``bash
claude plugins install claude-md-management@claude-plugins-official
``

1. Installation fails with EPERM errors

Expected Behavior

Either:

• Plugin installs successfully from within session, OR
• Clear error message indicating installation must be done outside an active session

Workaround

Run the install command manually in a separate terminal (outside the Claude Code session).

Environment

• macOS Sequoia (Darwin 24.6.0)
• Claude Code installed via Homebrew (@anthropic-ai/claude-code)
• Running from VSCode extension

Additional Context

The sandbox appears to block writes to .claude.json and session files during plugin installation. This prevents users from installing plugins when Claude suggests them during a conversation.