Secret Scanning Skill

Overview

This skill uses the GitHub MCP Server's run_secret_scanning tool to detect secrets in content, files, or git changes. It helps identify sensitive material like API keys, passwords, and credentials that could pose a security risk if exposed.

What counts as a secret?

In this context, values that grant access, impersonate a user or service, sign requests, or decrypt protected data are generally treated as secrets.

Treat these as high-confidence secret material:

• Access tokens, API keys, and bearer credentials
• Passwords, database DSNs with embedded credentials, and SMTP auth values
• Private keys, signing keys, certificates with private key blocks, and SSH keys
• OAuth client secrets, refresh tokens, and webhook secrets
• Cloud credentials (AWS/GCP/Azure) and CI/CD deployment credentials

Prefer context, not just regex:

• Values near names like password, token, secret, client_secret, private_key, or authorization are higher risk
• Long high-entropy strings in config files, scripts, and test fixtures deserve review even if unlabeled
• Treat uncertain findings as sensitive until verified

Not everything that looks random is a secret. Example placeholders such as YOUR_API_KEY_HERE, obvious test stubs, and documented sample values can be false positives.

Why this is important

This skill scans for secrets that could compromise security if leaked. A committed secret can persist in git history, trigger incident response, and block deployment at push protection checks.

Important: Only use this skill when a user explicitly asks to scan content or check for secrets. Do not run secret scanning unprompted or as part of general workflows.

Common Scenarios

User goal	How to respond	Tools needed
Check a config snippet or code paste	Scan as content	MCP
Check a specific file in the repo	Read file, then scan	Read + MCP
Check all staged changes before commit	Get diff, then scan	Bash(git:*) + MCP

Installation

Prerequisites & Inputs

GitHub MCP Server: The skill requires the GitHub MCP Server with the secret_protection toolset enabled. This repository includes a default .mcp.json configured for the GitHub MCP Server, allowing the skill to communicate with it out of the box.

Configure in your MCP settings:

{
  "mcpServers": {
    "github": {
      "type": "http",
      "url": "https://api.githubcopilot.com/mcp/"
    }
  }
}

Note: Cursor uses servers instead of mcpServers as the top-level key.

Required information for scanning:

• Repository owner: Usually available from git remote get-url origin or ask the user
• Repository name: Usually available from git remote get-url origin or ask the user
• Content to scan: Either a code snippet from the user, file content (read using the Read tool), or git diff output (from git diff)

If the user doesn't provide repository owner and repository name, ask for them before running the scan.

What NOT to scan: By default, avoid scanning large generated or vendor content (for example: node_modules/, build artifacts, compiled assets, or other machine-generated files) for performance and noise reduction. Files listed in .gitignore may still contain secrets (such as .env or local config), so only skip them if the user agrees; if the user explicitly asks to scan them, include them in the scan.

Scan Content

When to use: The user provides text or code snippets they want checked for secrets.

How: Use the run_secret_scanning tool with the content as input (as a single-item array).

Example

You: Check if this config snippet has secrets
User provides:
DB_PASSWORD=MyP@ssw0rd123
API_KEY=abc123xyz

Agent: I'll scan that for secrets.

     ⚠️ Found 2 potential secret(s):
     1. DB_PASSWORD value looks like a password
     2. API_KEY value looks like an API key

     Consider replacing hardcoded values with environment variables.

Scan File(s)

When to use: The user asks to check specific files in the repository for secrets.

How: Use the Read tool to get file contents, then pass them to run_secret_scanning.

Example (secrets found)

You: Check if config.py has secrets
Agent: I'll read and scan that file.

     ⚠️ Found 1 potential secret:
     - Line 10: database_password value looks like a password

     Suggestion: Move to environment variable or .env file.

Example (no secrets found)

You: Check if utils.js has any secrets
Agent: I'll read and scan that file.

     ✅ No secrets detected in utils.js

Scan Staged Changes

When to use: The user wants to check git staged changes for secrets before committing.

How: Use git diff --cached to get staged content, then pass it to run_secret_scanning.

Example (clean)

You: Check my staged changes for secrets before I commit
Agent: I'll scan your staged changes.

     ✅ No secrets found in staged changes. Safe to commit.

Example (secrets detected)

You: Scan my staged changes
Agent: I'll check your staged changes.

     ⚠️ Found 1 potential secret in staged changes:
     - database.js line 5: password value looks like a credential

     Suggestion: Unstage that change, move the credential to env vars, and restage.

How the Scan Works

When you call run_secret_scanning:

• Input: File contents to scan (passed as an array of strings), plus repository owner and name
• Process: GitHub's secret detection scans for patterns and context that match known secret types
• Output: List of potential secrets found with locations and confidence indicators

The tool works on content you provide. It doesn't need push access or special GitHub permissions.

Scanning Transparency

How Your Content Is Processed

When you request a scan, file contents are sent to GitHub's secret detection infrastructure. The scanning happens server-side against GitHub's known secret patterns. Scan results are returned without retaining the content on GitHub servers beyond the scan request.

What to Do With Results

If secrets are found:

• Obvious hardcoded values: Move them to environment variables or .env files
• Config files: Check if example.env or documentation exists that shows the expected structure
• Already committed: If the secret was already pushed, credential rotation may be needed (outside this skill's scope)

If no secrets are found:

• The scan completed successfully
• Check the output format in the scan result to make sure coverage was complete

Learn More

For more details on secret scanning, credential management, and GitHub security features:

• GitHub Secret Scanning Docs: How to enable and use secret scanning on repositories
• Credential Management Best Practices: Guidance on handling credentials safely
• GitHub Push Protection: Preventing secrets from reaching your repository