Prompt Injection Tester

Prompt injection is the #1 vulnerability in AI-powered applications (OWASP LLM01 2025). It occurs when an attacker crafts input that causes an AI model to ignore its system prompt and follow injected instructions instead — revealing confidential data, breaking role restrictions, or performing unauthorized actions.

Unlike traditional SQL injection or XSS, prompt injection exploits the fundamental nature of large language models: they process all text in their context window as instructions, regardless of source. An attacker who can get text into the model's context — via user input, a document, a webpage, or an API response — can potentially override your system prompt entirely. The OWASP Agentic AI guidelines highlight this risk as especially severe in autonomous agents where the model can take real-world actions.

Defending against prompt injection requires a layered approach: explicit role-locking, instruction override guards, output restrictions, confidentiality clauses, and defined behavior for unexpected inputs. No single guardrail is sufficient — attackers will find the gaps. This tool checks for the most commonly missing defenses and simulates real-world attack vectors so you can identify and fix them before deploying to production.