# What is prompt injection? How hidden instructions trick AI agents

Prompt injection is when text an AI agent reads, such as a web page, email, or file, contains instructions that try to take over what it does. Plain examples, why it matters more for agents, and how to limit the damage.

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## Steps

1. **Require approval for actions.** Anything that sends, posts, buys, deletes, or shares waits for your yes. This is the single most effective defense. See review before place.
2. **Limit what the agent can reach.** A fooled agent can only misuse tools it has. See connect only what you need.
3. **Keep reading and acting apart.** Let the agent research the open web with no access to your email or money in the same session. See separate browser profile for the agent.
4. **Cap spending.** If it can pay, use a capped card and an allowed-merchant list. See whitelist merchants only.
5. **Read the action, not the summary.** When you approve, check the real recipient, amount, and link, not just the agent’s description of them.

## FAQ

### What is prompt injection in simple terms?

Instructions hidden in text an AI agent reads, such as a web page or email, that try to make it do something you did not ask for.

### What is indirect prompt injection?

When the hidden instructions come from outside content the agent reads, not from the person using it. It is the main risk for agents that browse the web or read email.

### Can prompt injection steal my data?

It can try, if the agent has access to your data and a way to send it somewhere. Limiting access and approving every send blocks most of that.

### Does telling the agent to ignore outside instructions work?

It helps a little but is not reliable on its own. Back it up with approval for actions and limited access.

### Can prompt injection make an AI agent spend money?

Yes, if the agent can pay without asking. Use a capped card, an allowed-merchant list, and approval before every purchase.