Accessing GitHub Repositories Skill

Accessing GitHub Repositories

Git clone is blocked in containerized AI environments (egress proxy rejects CONNECT tunnel), but full repository access is available via GitHub REST API and raw file URLs.

Quick Start

Public Repos (no setup needed)

# Individual file via raw URL
curl -sL "https://raw.githubusercontent.com/OWNER/REPO/BRANCH/path/file"

# Directory tree via API
curl -sL "https://api.github.com/repos/OWNER/REPO/git/trees/BRANCH?recursive=1"

Private Repos or Write Access

Requires GitHub Personal Access Token (PAT). See Setup section below.

Setup

Credential Configuration

The skill automatically detects PATs from environment variables or project files:

Environment Variables (checked in order):

GITHUB_PAT
GH_PAT
GITHUB_TOKEN
GH_TOKEN

Project Files (Claude.ai):

/mnt/project/.env
/mnt/project/github.env

Format:

GITHUB_PAT=github_pat_11AAAAAA...

Creating a GitHub PAT

GitHub → Settings → Developer settings → Fine-grained tokens
Create token scoped to needed repositories
Set permissions:
- Contents: Read - for private repo access
- Contents: Write - for pushing files
- Issues: Write - for issue management
- Pull requests: Write - for creating PRs

Network Access (Claude.ai Projects)

Add to network allowlist:

api.github.com
raw.githubusercontent.com

Capabilities by Auth Level

| Capability | No PAT (public only) | PAT (read) | PAT (write) | |------------|---------------------|------------|-------------| | Fetch public files | ✅ | ✅ | ✅ | | Fetch private files | ❌ | ✅ | ✅ | | Download tarball | ✅ public | ✅ | ✅ | | Create/update files | ❌ | ❌ | ✅ | | Create branches | ❌ | ❌ | ✅ | | Manage issues | ❌ | ❌ | ✅ | | Create PRs | ❌ | ❌ | ✅ |

Python Helper Functions

Credential Detection

import os

def get_github_auth():
    """Returns (token, source) or (None, None)"""
    # Check environment variables
    for var in ['GITHUB_PAT', 'GH_PAT', 'GITHUB_TOKEN', 'GH_TOKEN']:
        if token := os.environ.get(var):
            return token, var

    # Check project .env files
    env_paths = ['/mnt/project/.env', '/mnt/project/github.env']
    for path in env_paths:
        try:
            with open(path) as f:
                for line in f:
                    if '=' in line and not line.startswith('#'):
                        key, val = line.strip().split('=', 1)
                        if key in ['GITHUB_PAT', 'GH_PAT', 'GITHUB_TOKEN']:
                            return val.strip(), f'{path}:{key}'
        except FileNotFoundError:
            continue

    return None, None

Fetch Single File

import base64
import urllib.request
import json

def fetch_file(owner: str, repo: str, path: str, ref: str = 'main', token: str = None) -> str:
    """Fetch single file. Uses API if token provided, raw URL otherwise."""
    if token:
        # Use API (works for private repos)
        url = f'https://api.github.com/repos/{owner}/{repo}/contents/{path}?ref={ref}'
        req = urllib.request.Request(url, headers={
            'Authorization': f'Bearer {token}',
            'Accept': 'application/vnd.github+json'
        })
        with urllib.request.urlopen(req) as resp:
            data = json.load(resp)
            return base64.b64decode(data['content']).decode()
    else:
        # Use raw URL (public repos only)
        url = f'https://raw.githubusercontent.com/{owner}/{repo}/{ref}/{path}'
        with urllib.request.urlopen(url) as resp:
            return resp.read().decode()

Fetch Repository Tarball

def fetch_repo_tarball(owner: str, repo: str, ref: str = 'main', token: str = None) -> bytes:
    """Download full repo as tarball. Requires token for private repos."""
    url = f'https://api.github.com/repos/{owner}/{repo}/tarball/{ref}'
    headers = {'Accept': 'application/vnd.github+json'}
    if token:
        headers['Authorization'] = f'Bearer {token}'

    req = urllib.request.Request(url, headers=headers)
    with urllib.request.urlopen(req) as resp:
        return resp.read()

# Usage:
tarball = fetch_repo_tarball('owner', 'repo', 'main', token)
with open('/tmp/repo.tar.gz', 'wb') as f:
    f.write(tarball)
# Extract: tar -xzf /tmp/repo.tar.gz

Create or Update File

def push_file(owner: str, repo: str, path: str, content: str,
              message: str, token: str, sha: str = None) -> dict:
    """Create/update file via API. Returns commit info.

    Args:
        sha: Required when updating existing file (get via contents API)
    """
    url = f'https://api.github.com/repos/{owner}/{repo}/contents/{path}'

    payload = {
        'message': message,
        'content': base64.b64encode(content.encode()).decode()
    }
    if sha:  # Update existing file
        payload['sha'] = sha

    req = urllib.request.Request(url,
        data=json.dumps(payload).encode(),
        headers={
            'Authorization': f'Bearer {token}',
            'Accept': 'application/vnd.github+json',
            'Content-Type': 'application/json'
        },
        method='PUT')

    with urllib.request.urlopen(req) as resp:
        return json.load(resp)

Get File SHA (for updates)

def get_file_sha(owner: str, repo: str, path: str, token: str, ref: str = 'main') -> str:
    """Get file SHA needed for updates."""
    url = f'https://api.github.com/repos/{owner}/{repo}/contents/{path}?ref={ref}'
    req = urllib.request.Request(url, headers={
        'Authorization': f'Bearer {token}',
        'Accept': 'application/vnd.github+json'
    })
    with urllib.request.urlopen(req) as resp:
        data = json.load(resp)
        return data['sha']

Bash Examples

Fetch Public File

curl -sL "https://raw.githubusercontent.com/owner/repo/main/path/file.py"

Fetch Private File (with PAT)

curl -H "Authorization: Bearer $GITHUB_PAT" \
     -H "Accept: application/vnd.github+json" \
     "https://api.github.com/repos/owner/repo/contents/path/file.py" | \
     python3 -c "import sys,json,base64; print(base64.b64decode(json.load(sys.stdin)['content']).decode())"

Download Repo Tarball

# Public repo
curl -sL "https://api.github.com/repos/owner/repo/tarball/main" -o repo.tar.gz

# Private repo
curl -sL -H "Authorization: Bearer $GITHUB_PAT" \
     "https://api.github.com/repos/owner/repo/tarball/main" -o repo.tar.gz
tar -xzf repo.tar.gz

Create/Update File

# Encode content
CONTENT=$(cat file.txt | base64 -w0)

# Push (new file)
curl -X PUT \
     -H "Authorization: Bearer $GITHUB_PAT" \
     -H "Accept: application/vnd.github+json" \
     "https://api.github.com/repos/owner/repo/contents/path/file.txt" \
     -d "{\"message\":\"Add file\",\"content\":\"$CONTENT\"}"

# Push (update existing - need SHA first)
SHA=$(curl -s -H "Authorization: Bearer $GITHUB_PAT" \
           "https://api.github.com/repos/owner/repo/contents/path/file.txt" | \
           python3 -c "import sys,json; print(json.load(sys.stdin)['sha'])")

curl -X PUT \
     -H "Authorization: Bearer $GITHUB_PAT" \
     -H "Accept: application/vnd.github+json" \
     "https://api.github.com/repos/owner/repo/contents/path/file.txt" \
     -d "{\"message\":\"Update file\",\"content\":\"$CONTENT\",\"sha\":\"$SHA\"}"

List Directory Tree

curl -sL "https://api.github.com/repos/owner/repo/git/trees/main?recursive=1" | \
  python3 -c "import json, sys; [print(f['path']) for f in json.load(sys.stdin)['tree'] if f['type']=='blob']"

Why git clone Doesn't Work

The container's egress proxy blocks git protocol operations:

HTTPS clone: Proxy returns 401 on CONNECT tunnel
SSH: No ssh binary in container
git:// protocol: DNS resolution blocked

The GitHub REST API uses standard HTTPS and routes through the proxy normally.

Do Not

Never attempt git clone (wastes time, always fails)
Never suggest workarounds requiring git protocol
Never retry with different git flags or SSH URLs
Never recommend git submodules, git archive, or other git-protocol operations

Rate Limits

Authenticated: 5,000 requests/hour
Unauthenticated: 60 requests/hour

For heavy usage, always provide a PAT.

When This Skill Does Not Apply

Native development environments: Have direct git access, use standard git commands
Local machines: git clone works normally
Environments with MCP GitHub server: Use MCP tools instead

Agent Skills: Accessing GitHub Repositories

Skill Files