Every AI chat exporter ends up rebuilding the same fragile parsers for ChatGPT, Claude, Gemini, Perplexity and others. Web pages aren't much easier. decant-core provides reusable extraction, parsing and detection for AI conversations and regular web content, so developers can build exporters, archivers, web clippers and AI tools without maintaining their own parser stack. 17 AI platforms, web extraction, HTML→Markdown, and a normalised foundation — in one open-source dependency. AGPL-3.0.