LochBot

LochBot is a free browser based prompt injection checker for people building chatbots. A developer pastes a system prompt and the tool analyzes its structure against 31 known injection attack patterns, then returns a security score from 0 to 100 with a letter grade from A to F. The patterns are grouped into seven categories: direct injection, context manipulation, delimiter attacks, data extraction, role play jailbreaks, encoding attacks and prompt leaking. Each failed check is rated critical, high, medium or low severity and comes with a specific fix suggestion that can be added to the prompt. Results can be exported as JSON for documentation, compliance reporting or a development workflow. The site also lists a short set of defensive practices, such as wrapping instructions in XML delimiters, forbidding instruction disclosure, blocking role changes, including refusal examples and declaring instructions immutable. The vendor is explicit about the limits. The checker looks for defensive language and structural elements in the prompt text; it does not test against a live AI model. All analysis runs client side in the browser, and the vendor states the prompt never leaves the user's machine. The tool is free to use, and the site publishes no paid plans.