Why Agents Need Tools › What Counts as a Tool?

When we talk about tools for AI agents, we mean any external function or service the agent can call to perform a specific task. This includes:

Computation tools:

• Calculator functions for precise math
• Data analysis libraries for statistics
• Code interpreters for running programs

Information retrieval tools:

• Web search APIs
• Database queries
• Document retrieval systems
• API calls to external services (weather, stocks, news)

Action tools:

• Email sending functions
• Calendar management APIs
• File system operations
• Payment processing APIs
• IoT device controls

Specialized tools:

• Image generation services
• Translation APIs
• Speech-to-text or text-to-speech services
• Domain-specific calculators (mortgage, tax, etc.)

The key characteristic of a tool is that it's deterministic and reliable. When you call a calculator with $1234 \times 5678$, you always get $7,006,652$. When you query a database for order #12345, you get the current status of that order. Tools provide ground truth that the agent can rely on.