---
type: "Glossary term"
title: "Prompt injection"
description: "Malicious instructions hidden in tool descriptions or retrieved content."
tags: [glossary]
generated: { by: human:crpage, at: 2026-07-09T09:44:00Z }
aliases: "prompt injection; context injection; indirect injection"
status: stable
---

# Definition
Malicious instructions smuggled via tool descriptions, retrieved content or untrusted annotations. [MCP](../standards/mcp.md) warns that tool descriptions should be treated as **untrusted** unless from a trusted server.

# Used in this bundle
Appears in: [failure-taxonomy](../document/themes/failure-taxonomy.md), [mcp](../standards/mcp.md).

# Related terms
[least privilege](least-privilege.md).