Building AI Agents with Tool Use and Function Calling

AI agents that can use tools and call functions are transforming how we build applications. This guide covers the architecture patterns for production-ready agent systems.

Core Components

• Tool Definitions: JSON schemas that describe available functions
• Agent Loop: Think → Act → Observe cycle
• Memory Management: Maintaining context across interactions
• Error Handling: Graceful degradation when tools fail

Popular Frameworks

LangChain, LlamaIndex, and Anthropic's SDK provide robust abstractions for building agents. For production, consider Claude's tool use with structured outputs for reliable function calling.

Best Practices

1. Design tools with clear, singular purposes
2. Implement timeouts for external API calls
3. Use sandboxing for code execution tools
4. Maintain audit trails of all tool invocations

Security Considerations

Never trust tool outputs blindly. Treat all tool results as untrusted input and validate before using in downstream decisions.