System prompt
A system prompt is the instruction set an application gives an AI model before a conversation or task starts, establishing its role, behavior boundaries and what it's permitted to do, as distinct from the user's own input and from any content the model reads afterward while performing a task. Because a model reads its system prompt and the content it later encounters -- a web page, a document, a tool's response -- through the same text channel, it doesn't automatically know which parts are trusted instructions and which are untrusted data, which is the root cause of prompt injection. AdminKit's guide to securing an MCP server flags this directly: text that merely resembles system-prompt-style instructions, embedded in otherwise ordinary tool output, is a common red flag worth filtering before it reaches the model, precisely because the model can't reliably tell a genuine system prompt from an imitation.
By AdminKit team, Netbase JSC · Updated