API Key (Glossary): What It Means for Agent Security
API keys authenticate your agent to external services. Learn what they are, why leaks are dangerous, and how to protect them.
API Key
Definition: An API key is a secret credential that authenticates your agent (or application) to an external service.
Why It Matters for Agents
Tool-enabled agents often need API keys to access external services: databases, AI models, payment processors, email providers.
A leaked API key means:
| Risk | Impact |
|---|---|
| Unauthorized access | Attacker uses your service quota |
| Financial damage | Bills charged to your account |
| Data breach | Access to data your key can reach |
| Reputation harm | Actions taken in your name |
Real-World Incidents
API key leaks are common and costly:
- GitHub scans find thousands of exposed keys daily
- Cloud provider keys have led to six-figure bills from crypto mining
- AI API keys can drain credits in minutes
How to Protect API Keys
Step 1: Never Hardcode
❌ API_KEY = "sk-abc123..." // In code
✅ API_KEY = process.env.API_KEY // From environmentStep 2: Use Secrets Management
- Environment variables for local development
- Secrets managers for production (AWS Secrets Manager, HashiCorp Vault)
- Never commit
.envfiles to version control
Step 3: Scope Permissions
Many services let you create limited keys:
- Read-only vs read-write
- Specific resources only
- Rate limits and quotas
Step 4: Rotate Regularly
- Set rotation schedules (30-90 days)
- Revoke immediately if suspected leak
- Monitor for unusual usage
Step 5: Monitor Usage
- Enable logging on your API keys
- Set up alerts for unusual patterns
- Review access logs regularly
Common Mistakes
| Mistake | Better Approach |
|---|---|
| Committing keys to git | Use .gitignore and environment variables |
| Sharing keys in chat | Use secure secrets sharing tools |
| Using one key everywhere | Create separate keys per environment/service |
| Never rotating keys | Schedule regular rotation |
Agent-Specific Risks
Agents introduce unique API key risks:
- Prompt injection could trick an agent into revealing keys
- Log exposure might capture keys in debug output
- Over-scoped keys give agents more access than needed
Apply least privilege to agent API keys.