API, Database and Computer-Use Tools

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.

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.

Quick check: When is a computer-use tool the best choice?

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