Self-hosted alternatives to doublecheck

D

doublecheck

Three-layer verification pipeline for AI output

doublecheck is an agent skill from the github/awesome-copilot collection that runs a three-layer verification pipeline on AI-generated output. Its goal is not to declare what is true, but to extract every verifiable claim in a response, find sources the user can check independently, and flag anything that looks like a hallucination pattern. It works in two modes. In active mode, invoked without specific text, it stays on for the rest of the conversation and adds an inline verification summary after each substantive response, and the user can ask for the full report on any response or turn the mode off. In one-shot mode it checks a given piece of text on request. Before any substantive response, the skill classifies whether the response contains verifiable claims, and it applies its rules to the claims it finds. Web search is used to locate supporting or contradicting sources, and an adversarial review pass looks for weak points in the claims. The skill is useful when a person relies on an AI answer for facts, and wants a trail to check. Its findings depend on the search results, which can be incomplete, so a claim the skill cannot source is not thereby false, and the user should check the sources that matter. The skill is installed with the skills CLI from the github/awesome-copilot repository. Its skills.sh page showed about 4.2K installs, with Gen Agent Trust Hub and Socket passing and Snyk showing a warning at the time of the scan.