Tool Integration

Models are more useful when they can act.

Why Tools Matter

Models can read files, run code, query APIs
Extends capability beyond text generation
Enables agentic workflows
Grounds output in real data

Integration Patterns

Function Calling

Define functions the model can invoke
Model decides when/how to call
Results feed back into generation

MCP (Model Context Protocol)

Standardized tool interface
Server provides tools, resources, prompts
Client (harness) orchestrates

Direct API Access

Model generates API calls
System executes and returns results
Verification of API responses

Tool Design Principles

Clear, unambiguous tool descriptions
Minimal required parameters
Useful error messages
Idempotent when possible

Security Considerations

What can the model access?
Permission scoping
Audit logging
Sandboxing execution

Anti-patterns

Too many tools (model gets confused)
Vague tool descriptions
No error handling
Trusting tool output without validation