Tools, multimodal inputs, and agent boundaries
Keep information from a webpage from becoming permission to act.
Reviewed: 2026-10-03
Source-based teaching example · Fictional data
Narration: Microsoft Mark · locally synthesized

00:00:00.000 — What you will learn

Keep information from a webpage from becoming permission to act.

Visual description:
Keep information from a webpage from becoming permission to act.

00:00:06.792 — The idea

A page may contain text that tries to redirect the assistant. Treat that text as something to inspect, not a command from the user. Limit what the tools can actually do.

Visual description:
A page may contain text that tries to redirect the assistant. Treat that text as something to inspect, not a command from the user. Limit what the tools can actually do.

00:00:20.708 — One useful term

Prompt injection. Instructions in untrusted content that try to change the assistant’s task. They may be visible or hidden.

Visual description:
Instructions in untrusted content that try to change the assistant’s task. They may be visible or hidden.

00:00:31.958 — A worked example · 1

The task is to summarize three public pages. One page asks the assistant to upload local files. That request is outside the task.

Visual description:
The task is to summarize three public pages. One page asks the assistant to upload local files. That request is outside the task.

00:00:44.417 — A worked example · 2

Read-only tools with no file-upload access help block that action.

Visual description:
Read-only tools with no file-upload access help block that action.

00:00:51.500 — Your turn to think

Does a sentence on a webpage give permission to upload files? Pause and decide before continuing.

Visual description:
Does a sentence on a webpage give permission to upload files?
Pause the video if you need more time.

00:01:08.875 — Why this answer works

No. The same applies if the sentence appears in an image. Real permissions must be enforced outside the prompt.

Visual description:
No. The same applies if the sentence appears in an image. Real permissions must be enforced outside the prompt.

00:01:19.333 — Check 1

Use only the needed sources and tools.

Visual description:
Use only the needed sources and tools.

00:01:24.750 — Check 2

Do not add access when the task fails.

Visual description:
Do not add access when the task fails.

00:01:30.333 — Check 3

Stop when the approved limits are reached.

Visual description:
Stop when the approved limits are reached.

00:01:35.708 — Now try a different case

Open the lesson and try its different practice case. Use every check in the full task. Watching alone does not mark the lesson complete.

Visual description:
Open the lesson
Try the new case
Check and revise
The full task and its requirements are in the linked lesson.