# API, Database and Computer-Use Tools — AI Agents and Tool Use

Source: https://www.geekswithgeeks.com/en/ai-agents-mcp/kinds-api-computer

> Choose between structured API tools and screen-driving tools and prefer the first when possible.

## Structured beats screen-scraping

Where a system has an API or database, wrap it in a typed tool: it is fast, testable and easy to permission. For software with no API, **computer-use** tools let a model look at screenshots and click or type like a person. That is powerful but slower, costlier and more error-prone, so treat it as a fallback and add confirmations for anything irreversible.

## Choosing the interface

Prefer the first line that applies.

```text
1. A documented API exists          -> typed API tool
2. A database you may query         -> read-only SQL tool (parameterised)
3. Files in a workspace             -> file read/write tools with path limits
4. Only a graphical interface       -> computer-use tool + human confirmation
```

## Wrap, do not expose raw SQL

Prefer narrow tools such as `get_orders_for_customer(id)` to a free-form SQL tool. If you must allow SQL, use a read-only user, a statement timeout and a row limit.

**Quiz:** When is a computer-use tool the best choice?

- [x] When the software has no API and only a graphical interface
- [ ] Whenever an API exists
- [ ] Never
- [ ] Only for reading text files

*Answer:* When the software has no API and only a graphical interface. Structured APIs are better; screen control is the fallback when nothing else exists.