: Give It Tools — Talking to Machines
5

Chapter Five

Give It
Tools

The leap from "answer questions"
to "take actions."

Up until now, every AI interaction you've had follows the same pattern. You type something. The AI types something back. Text in, text out. A really sophisticated autocomplete. But here's the thing: that's not the ceiling. It's just the floor.

What if the AI could do things? Not just tell you about the weather, but actually check the forecast. Not just write code, but run it and tell you what happened. Not just suggest what to Google, but search the web itself and bring back what it found.

That's what tool use is. And it changes everything about what AI can be.

Beyond Text-In, Text-Out

Think about what happens when you ask a chatbot: "What time is it in Tokyo right now?" The AI doesn't actually know. It was trained on data that's months or years old. It has no clock. So it does the only thing it can — it guesses, based on patterns in its training data. Sometimes it's close. Sometimes it's hilariously wrong.

Without tools

User: What time is it in Tokyo?
AI: It should be around 2:30 PM JST. (Just guessing)

Now give that same AI a tool — a simple function that returns the current time in any timezone. Suddenly:

With tools

User: What time is it in Tokyo?
AI thinks: I have a timezone tool. Let me use it.
AI calls: get_time("Asia/Tokyo")
Tool returns: 14:47 JST
AI: It's currently 2:47 PM in Tokyo (JST). (Verified)

Same question. Completely different reliability. The AI didn't get smarter — it got connected. It can now reach outside its own brain and interact with the real world.

How Tool Use Actually Works

Here's the mental model. When you give an AI access to tools, you're handing it a toolbox and saying: "Here are things you can do. For each tool, here's what it's called, what it accepts, and what it returns. You decide when to use them."

The AI doesn't blindly use every tool on every request. It reasons about which tools are relevant, decides whether to use one, formulates the right input, calls the tool, reads the result, and then incorporates that result into its response. This process is called function calling — and it follows a remarkably consistent loop.

Observe. Read the user's request and any available context.

Think. Decide: "Do I need a tool for this, or can I answer directly?"

Act. Call the appropriate tool with the right arguments.

Observe. Read the tool's result.

Respond. Synthesize everything into a useful answer.

The AI isn't executing a script. It's making a judgment call every time: "Is this a situation where I should use a tool, or can I handle it myself?"

This is the agent loop — observe, think, act, observe, respond. And it's the same loop whether the AI has one tool or a hundred. The more tools you give it, the more capable it becomes. But also, the more trust you need to place in its judgment about which tool to use and when.

Seven Tools That Change Everything

There are hundreds of specific tools AI can use, but they mostly fall into seven categories. Each one extends what AI can do in a fundamentally different way. Some give it knowledge (web search, databases). Some give it abilities (code execution, image generation). Some give it hands (file editing, API calls).

Click any tool below to see the AI's full reasoning process — from recognizing it needs a tool, to calling it, to using the result.

Tool Catalog

Click a tool to see the AI use it

7 tools

The Trust Question

Once AI can do things — not just talk about them — a new question emerges. A question that has nothing to do with technology and everything to do with you:

How much should the AI do on its own before checking with you?

This isn't a technical question — it's a human one. And the answer depends on three things:

1

Stakes

What's the worst that could happen? Summarizing an article wrong is annoying. Deleting the wrong files is a disaster. Higher stakes demand more human oversight.

2

Reversibility

Can you undo it? Editing a file in a git repo is easily reversed. Sending an email to your boss is not. Irreversible actions should almost always require your approval.

3

Trust

How well do you know this tool? A calculator you've used a hundred times deserves more autonomy than a brand-new plugin you've never tested. Trust is earned, not assumed.

The spectrum of autonomy

It's not all-or-nothing. The best AI workflows give the AI freedom on low-stakes, reversible tasks while keeping humans in the loop for high-stakes, irreversible ones. Your job is to design the boundary.

Trust Thermometer

How much autonomy would you give?

1 / 8
low stakes

Scenario

Your AI agent wants to: summarize an article you're reading

The Tool-Use Mindset

There's a subtle shift that happens when you start thinking about AI as a tool-user instead of just a text-generator. You stop asking "What can the AI say about this?" and start asking "What can the AI do about this?"

Instead of asking the AI to describe how to analyze data, you give it a code execution tool and watch it write and run the analysis. Instead of asking for links to research, you give it web search and let it find and synthesize the information itself. The output goes from "here's what you could do" to "here's what I just did."

Old mindset

"Explain how I would calculate the compound interest on $5,000 at 6.5% over 10 years."

Tool-use mindset

"Calculate the compound interest on $5,000 at 6.5% APR compounded monthly for 10 years. Show me the exact number."

The first prompt gets you a tutorial. The second gets you an answer. With tools, the AI goes from advisor to assistant — from someone who tells you what to do, to someone who actually does it.

Key Concepts

The Agent Loop

Observe → Think → Act → Observe, repeat until done.

Tool Use / Function Calling

AI decides when to call functions and what arguments to pass.

Autonomy vs. Control

How much should agents do without asking? Depends on stakes, reversibility, and trust.

An AI with tools isn't just smarter. It's a different kind of thing entirely — one that can act, not just advise.

In the next chapter, we take this further. Tools are the building blocks. Now it's time to wire them together into something that can pursue goals on its own. It's time to build agents.