Unable to install this public marketplace via Claude Code due to upstream clone bug (anthropics/claude-code#27251)

[spiveym]

Update: Root cause identified and filed upstream as anthropics/claude-code#27251.

Since v2.1.7, Claude Code passes --recurse-submodules to git clone for marketplace installs. GitHub's June 2025 security advisory (Git security vulnerabilities announced) explicitly recommends avoiding git clone with --recurse-submodules against untrusted repositories due to CVE-2025-48384 (code execution via submodule path manipulation) and CVE-2025-48385 (arbitrary file writes via bundle protocol injection).

Therefore, corporate endpoint security tools (CrowdStrike Falcon, Uptycs Protect, etc.) enforce this by killing any git process whose argv contains --recurse-submodules, resulting in instant SIGKILL (exit 137) with empty stderr - which is why the error message is always blank:

✘ Failed to add marketplace: Failed to clone marketplace repository:

Confirmed on macOS with CrowdStrike + Uptycs. The kill is argv pattern-based, not behavioral, and even local clones of repos with no submodules get killed. This affects all marketplace installs including this Anthropic marketplace on startup (Failed to install Anthropic marketplace · Will retry on next startup).

Replacing --recurse-submodules with -c "submodule.recurse=true" avoids the kill while achieving the same behavior.

See anthropics/claude-code#27251 for full binary analysis, version-by-version confirmation, reproduction steps, and suggested fixes.

Workaround: Manual clone + registry entry:

git clone https://github.com/anthropics/knowledge-work-plugins.git \
  ~/.claude/plugins/marketplaces/knowledge-work-plugins

Then add to ~/.claude/plugins/known_marketplaces.json:

"knowledge-work-plugins": {
  "source": { "source": "github", "repo": "anthropics/knowledge-work-plugins" },
  "installLocation": "<HOME>/.claude/plugins/marketplaces/knowledge-work-plugins",
  "lastUpdated": "2026-02-20T00:00:00.000Z"
}

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Original issue description preserved below for context:
I've been unable to install this marketplace via Claude Code (v2.1.45, macOS Darwin 25.2.0) using the methods provided here. This is a public repo that should require zero authentication, but both HTTPS and SSH clone attempts fail silently. I could install via a manual workaround, but this appears to be a more pervasive issue.

Repro

claude plugin marketplace add anthropics/knowledge-work-plugins

Output

  Adding marketplace...
  SSH not configured, cloning via HTTPS: https://github.com/anthropics/knowledge-work-plugins.git
  Refreshing marketplace cache…
  Cloning repository: https://github.com/anthropics/knowledge-work-plugins.git
  HTTPS clone failed, retrying with SSH: git@github.com:anthropics/knowledge-work-plugins.git
  Refreshing marketplace cache…
  Cloning repository: git@github.com:anthropics/knowledge-work-plugins.git
  ✘ Failed to add marketplace: Failed to clone marketplace repository:

I get the same result with:

• /plugin marketplace add anthropics/knowledge-work-plugins (TUI)
• /plugin marketplace add https://github.com/anthropics/knowledge-work-plugins.git (full URL)
• /plugin marketplace add /tmp/test-kwp (local clone — blocked by reserved name validation)

Environment

• git clone https://github.com/anthropics/knowledge-work-plugins.git works fine from the terminal
• gh auth status shows authenticated (keyring, HTTPS protocol)
• gh auth setup-git run, no effect
• GITHUB_TOKEN exported via gh auth token, no effect
• GIT_TRACE=1 and GIT_TRACE=/tmp/file produce no output — suggesting Claude Code is not invoking system git at all
• Git credential helper: osxkeychain

Root cause

This appears to be a Claude Code clone subprocess bug, not an issue with this repo. However I believe this needs eyes aside from the issues that were filed upstream at anthropics/claude-code#18001 (see also anthropics/claude-code#13553).