Install Private Plugin

Configure git authentication so that /plugin marketplace add can access private GitHub repositories from within a Codespace.

Why This Is Needed

Claude Code's /plugin marketplace add uses an internal git library that does not read Codespace credential helpers. The auto-provisioned credential helper (/.codespaces/bin/gitcredential_github.sh) is scoped to only the repo the Codespace was created from. To clone a different private repo, git needs a credential helper that can authenticate to it.

Parse Arguments

Extract from $ARGUMENTS:

• Arg 1 (required): GitHub repository URL or shorthand
  • Full URL: https://github.com/owner/repo
  • Shorthand: github.com/owner/repo or owner/repo

Normalize all formats to extract OWNER/REPO.

If no arguments provided, show the Troubleshooting section and stop.

---

Workflow

Step 1: Check gh CLI authentication

gh auth status 2>&1

If gh is not authenticated at all, jump to Manual Setup below.

Step 2: Test repo access via gh CLI

gh api repos/OWNER/REPO --jq '.full_name' 2>&1

If successful: The current gh auth token can access the repo. Proceed to Step 3.

If failed (404 or 403): The token doesn't have access to this repo. Output:

Error: Your current gh auth token cannot access OWNER/REPO.

Your gh CLI is authenticated but the token doesn't have permissions for this
repository. To fix this:

1. Go to: github.com > Settings > Developer settings > Personal access tokens
2. Edit the token shown in `gh auth status`
3. Under "Repository access", add OWNER/REPO
4. Ensure "Contents: Read-only" and "Metadata: Read-only" are set
5. Save, then re-run: /install-private-plugin OWNER/REPO

Stop here if access check fails.

Step 3: Configure gh as git credential helper

gh auth setup-git 2>&1

This registers the gh CLI as a git credential helper in ~/.gitconfig. When any git client (including Claude Code's internal library) needs credentials for a GitHub repo, it asks gh, which provides the authenticated token.

Step 4: Verify git access

git ls-remote https://github.com/OWNER/REPO 2>&1 | head -3

If successful: Proceed to Step 5.

If failed: The credential helper didn't take effect. Try the fallback:

# Check if a classic PAT is in use (starts with ghp_)
TOKEN=$(gh auth token 2>/dev/null)
if [[ "$TOKEN" == ghp_* ]]; then
    # Classic PATs work with x-access-token URL rewrite
    git config --global url."https://x-access-token:${TOKEN}@github.com/OWNER/REPO".insteadOf "https://github.com/OWNER/REPO"
    git ls-remote https://github.com/OWNER/REPO 2>&1 | head -3
fi

If still failing, show Troubleshooting section and stop.

Step 5: Confirm and instruct

Output:

Git authentication configured for OWNER/REPO.

Now run:
  /plugin marketplace add https://github.com/OWNER/REPO

Note: After a Codespace rebuild, re-run these commands:
  gh auth setup-git
  /plugin marketplace add https://github.com/OWNER/REPO

---

Manual Setup

If gh CLI is not authenticated, walk the user through setup:

Option A: Use an existing Codespace secret (recommended)

If GH_TOKEN or another env var already contains a PAT:

# Check for existing PAT env vars
env | grep -E '^(GH_TOKEN|GITHUB_PAT|REGGIE_PAT)=' | sed 's/=.*/=***/'

If a PAT is found:

echo "$PAT_VALUE" | gh auth login --with-token 2>&1
gh auth setup-git 2>&1

Then return to Step 2 to verify access.

Option B: Create a new PAT

1. Go to github.com > Settings > Developer settings > Personal access tokens > Fine-grained tokens
2. Click "Generate new token"
3. Configure:
   • Token name: codespace-private-plugins
   • Expiration: 90 days (or longer)
   • Repository access: Select the private repo(s) you need
   • Permissions: Contents (Read-only), Metadata (Read-only)
4. Click "Generate token" and copy it
5. Store as a Codespace secret:
   • github.com > Settings > Codespaces > Secrets > New secret
   • Name it (e.g., PLUGIN_PAT) and paste the token
   • Grant access to your Codespace's repo
6. Rebuild the Codespace to inject the secret
7. Re-run this command

---

Troubleshooting

"Write access to repository not granted" (403)

The token doesn't have permissions for this repo. Edit the token in GitHub Settings > Developer settings > Personal access tokens and add the repo.

"Invalid username or token"

Fine-grained PATs (github_pat_...) do not work with the x-access-token:TOKEN@github.com URL rewrite format. Use gh auth setup-git instead, which handles all PAT types correctly.

Plugin install still fails after git auth works

Claude Code's plugin system may cache auth failures. Try:

1. Delete any leftover marketplace directories: rm -rf ~/.claude/plugins/marketplaces/temp_*
2. Re-run /plugin marketplace add https://github.com/OWNER/REPO

Auth doesn't persist after Codespace rebuild

~/.gitconfig is ephemeral in Codespaces. Add to .devcontainer/postCreateCommand:

"postCreateCommand": "gh auth setup-git"

Notes

• gh auth setup-git registers gh as a credential helper for all GitHub repos the token can access — not just one specific repo.
• This is safe in Codespaces (single-user, ephemeral environment).
• For non-GitHub repos (GitLab, Bitbucket), the URL rewrite approach with a classic PAT is still the recommended method.