Cross Context: A Browser Extension for Seamless AI Chat Migration

Cross Context is a new open-source browser extension designed to eliminate the friction of moving AI conversations between different LLM platforms. By allowing users to migrate entire chat histories—including code, architectural decisions, and error logs—in a single click, it removes the need for manual copy-pasting. The tool functions entirely within the browser sandbox, ensuring privacy by avoiding cloud-based storage. It features a sophisticated context-engineering pipeline that performs priority scoring, deduplication, and truncation to ensure that transferred data remains relevant and within token limits. The extension supports major platforms like Claude, ChatGPT, Gemini, Grok, and Perplexity. Built using vanilla JavaScript and Chrome Manifest V3, Cross Context aims to improve developer productivity by enabling seamless transitions between models, including local open-weight options like Gemma, without requiring third-party sync services or external account dependencies.