Description

/plugin marketplace add and /plugin install commands fail with Error: Failed to clone marketplace repository / Error: Failed to install: Failed to clone repository. The internal git clone mechanism used by Claude Code fails silently, while git clone from the terminal works perfectly.

Steps to Reproduce

1. Run /plugin marketplace add anthropics/claude-plugins-official
2. Observe: Error: Failed to clone marketplace repository:
3. Also tried: /plugin marketplace add https://github.com/anthropics/claude-plugins-official.git — same error
4. Run /plugin install slack@claude-plugins-official (after manual marketplace registration)
5. Observe: Error: Failed to install: Failed to clone repository

Meanwhile, from the terminal:

git clone https://github.com/anthropics/claude-plugins-official.git  # succeeds
git ls-remote https://github.com/slackapi/slack-mcp-plugin.git HEAD  # succeeds

Workaround

Manually cloning the marketplace repo and writing ~/.claude/plugins/known_marketplaces.json allows the marketplace to be listed, but individual plugin installs still fail due to the same clone issue.

{
  "claude-plugins-official": {
    "source": {
      "source": "github",
      "repo": "anthropics/claude-plugins-official",
      "ref": "main"
    },
    "installLocation": "~/.claude/plugins/marketplaces/claude-plugins-official",
    "lastUpdated": "2026-02-24T18:00:00.000Z"
  }
}

Environment

• Claude Code version: 2.1.53
• OS: macOS 26.3 (Darwin 25.3.0, build 25D125)
• Git: /usr/bin/git version 2.50.1 (Apple Git-155)
• No git URL rewrites configured (git config --global --get-regexp 'url\.' returns empty)
• No proxy configured
• Git signing: SSH-based (gpg.format=ssh)

Expected Behavior

/plugin marketplace add anthropics/claude-plugins-official should clone the repository and register the marketplace. /plugin install <name> should clone the plugin repo and install it.

Actual Behavior

Both commands fail with a silent clone error. No additional error details are provided beyond "Failed to clone marketplace repository:" / "Failed to clone repository".

Additional Context

The error message after the colon is empty, suggesting the underlying git error is not being captured or propagated. More verbose error output would help diagnose whether this is a network, auth, sandboxing, or path issue.