[BUG] plugin install copies gitignored files, including a root .env, from a directory marketplace

Preflight

• Searched open issues for plugin cache and gitignore reports; found none matching.
• Single bug report.
• Running the latest version (2.1.266).

What's Wrong?

claude plugin install and claude plugin update copy the marketplace root into ~/.claude/plugins/cache/<marketplace>/<plugin>/<version>/. When the marketplace source is a directory, which is the local plugin development path, the copy includes files git ignores.

Measured on my checkout (github.com/bostonaholic/team, 90 skills and 13 agents):

• cache copy: 128M
• content tracked by git: 4.5M
• node_modules/ accounts for 51M of that difference. The rest is local scratch: .playwright-mcp/, .claude/worktrees/, .agents/friction-log/.

The copy already excludes .git, so some filtering happens, but it does not read .gitignore.

.gitignore is also where local secrets go by convention. My repo reserves a root .env for the API key its eval suite reads. I confirmed that file gets copied by writing a probe value to it and reinstalling:

$ cat ~/.claude/plugins/cache/team-dev/team/0.97.0-claude.20260910173552/.env
TEAM_DEV_COPY_PROBE=not-a-real-secret

The install prints no warning, and the copied file stays until the install is replaced.

What Should Happen?

When the marketplace source is a directory, skip files git ignores, honoring global excludes and core.excludesFile. An explicit exclude list in marketplace.json or plugin.json would work too.

Steps to Reproduce

1. Clone a plugin repo whose .gitignore covers node_modules/ and a root .env.
2. bun install (or npm install), and write any value to .env.
3. claude plugin marketplace add <path> --scope user
4. claude plugin install <plugin>@<marketplace> --scope user
5. ls -A ~/.claude/plugins/cache/<marketplace>/<plugin>/<version>/ shows both node_modules/ and .env in the copy.

Is this a regression?

Unknown. This is the first version I have measured.

Claude Code Version

2.1.266

Platform

macOS (arm64)

Operating System

macOS 26.6.2

Terminal/Shell

zsh

Additional Information

--plugin-dir skips the copy for a session, and I use it while iterating. My dev install script goes through plugin install so the install I test is the one users get, and that path is where the ignored files come along.