AI Agent Security: 10 Best Practices for 2026

As AI agents gain more autonomy, security becomes critical. Here are 10 practices to keep your agents safe.

1. Implement Input Validation

Never trust user input blindly.

Do This:

Sanitize all inputs
Set character limits
Validate data types
Block known attack patterns

Avoid This:

Passing raw input to LLMs
Assuming inputs are safe

2. Use Principle of Least Privilege

Agents should only access what they need.

✅ Read-only access to customer data
❌ Full admin access to database

3. Add Human-in-the-Loop for Critical Actions

Some decisions need human approval:

Financial transactions above threshold
Data deletion
Account modifications
External communications

4. Monitor and Log Everything

Track:

All agent decisions
API calls made
Data accessed
Errors encountered
Unusual patterns

5. Implement Rate Limiting

Prevent runaway agents:

Resource	Recommended Limit
API calls	100/minute
Database queries	50/minute
External requests	20/minute
LLM tokens	Budget-based

6. Sandbox Sensitive Operations

Run risky operations in isolated environments:

Code execution
File system access
Network requests
Data transformations

7. Defend Against Prompt Injection

Attackers try to manipulate agents through clever prompts.

Protection strategies:

Separate system and user prompts
Use prompt templates
Filter suspicious patterns
Validate output format

8. Encrypt Data in Transit and at Rest

Non-negotiable security basics:

TLS for all communications
Encrypted database storage
Secure API keys management
Regular key rotation

9. Plan for Failure

What happens when your agent:

Makes a wrong decision?
Gets stuck in a loop?
Accesses incorrect data?
Becomes unresponsive?

Have rollback procedures ready.

10. Regular Security Audits

Schedule quarterly reviews:

Penetration testing
Access control audit
Dependency vulnerability scan
Compliance verification

Quick Security Checklist

□ Input validation implemented
□ Access controls configured
□ Human approval for critical actions
□ Comprehensive logging enabled
□ Rate limiting active
□ Sandboxing for risky operations
□ Prompt injection defenses
□ Encryption enabled
□ Failure procedures documented
□ Audit schedule set

Need a security review for your AI agents? Our experts can help.