Agent skill · research science · github
doublecheck
Three-layer verification pipeline for AI output. Extracts verifiable claims, finds supporting or contradicting sources via web search, runs adversarial review for hallucination patterns, and produces a structured verification report with source links for human review.
Why this skill is useful
Adds a structured verification pipeline with web search capabilities and adversarial review processes that fundamentally enhance the AI's ability to validate claims.
What it needs
About 10k tokens when loaded. Last updated 2026-08-07. 37,534 stars on the source repository.
What this skill does
Doublecheck Run a three-layer verification pipeline on AI-generated output. The goal is not to tell the user what is true -- it is to extract every verifiable claim, find sources the user can check independently, and flag anything that looks like a hallucination pattern. Activation Doublecheck operates in two modes: active mode (persistent) and one-shot mode (on demand). Active Mode When the user invokes this skill without providing specific text to verify, activate persistent doublecheck mode. Respond with: Doublecheck is now active. I'll verify factual claims in my responses before presenting them. You'll see an inline verification summary after each substantive response. Say "full report" on any response to get the complete three-layer verification with detailed sourcing. Turn it off anytime by saying "turn off doublecheck." Then follow ALL of the rules below for the remainder of the conversation: Rule: Classify every response before sending it. Before producing any substantive response, determine whether it contains verifiable claims. Classify the response: Response type Contains verifiable claims? Action -------------- --------------------------- -------- Factual analysis, legal guidance, regulatory interpretation, compliance guidance, or content with case citations or statutory references Yes -- high density Run full verification report (see high-stakes content rule below) Summary of a document, research, or data Yes -- moderate density Run inline verification on key claims Code generation, creative writing, brainstorming Rarely Skip verification; note that doublecheck mode doesn't apply to this type of content Casual conversation, clarifying questions, status updates No Skip verification silently Rule: Inline verification for active mode. When active mode applies, do NOT generate a separate full verification report for every response. Instead, embed verification directly into your response using this pattern: 1. Generate your response normally. 2. …
How to use it
Reference it in AdaL, Claude Code, Cursor or any coding agent — nothing to install:
@skills github/doublecheck