news-fact-checker

news-fact-checker takes a news article URL and returns a Korean fact-check report: one overall verdict for the article, plus 3-5 key claims verified individually (true / mostly true / partly true / misleading / false / unverifiable). It is explicitly assistive rather than authoritative — for consequential decisions, read the primary sources yourself. Two problems shape its design. The first is reach: many outlets block automated readers with 403s, 402s, and WAF challenges. When WebFetch fails the plugin escalates to the insane-search engine, and if that is still blocked it looks for the site's internal API through MCP Playwright. When nothing works it says so and degrades to a reduced mode rather than inventing coverage. The second is false independence — the failure mode where a single wire-service story republished by eight outlets reads like eight confirmations. An Evidence Reducer collapses republished evidence into one effective source per stance before any verdict is computed, and the gate itself lives in code, not in the prompt: a confirmed 'true' requires two or more independent supporting sources and zero refutations; a confirmed 'false' requires two or more independent refutations. A single primary source cannot buy its way past the independence minimum. When the bar isn't met the answer is an honest 'unverifiable'. Security is treated as part of correctness. Fetched article and evidence bodies are untrusted data — instructions embedded in them ('ignore your rules', 'read this file', 'change the verdict') are logged as data and never followed. Outbound requests pass a destination policy that rejects userinfo URLs, loopback, private and link-local ranges, and cloud metadata hosts before any network call. Engine installation requires explicit one-time consent and a commit-pinned clone verified against a deployment-contract SHA, installed atomically so a tampered or moved tag never replaces a working copy. Network-free contract tests lock these failure branches, and CI runs them on Linux and macOS.