Show HN: Cont3xt – Infinite context window on laptop (github.com)

Cont3xt (v0.1.1) is an MVP MCP stdio server that gives agents and LLMs a “virtual infinite” rolling context window on your laptop: it continuously stores conversation chunks and surfaces the most relevant memories within a strict token budget. Designed to plug into the Cline VS Code extension, it runs locally (SQLite by default) with zero external services required, making it useful for private, offline workflows like guided code edits, multi-step planning, and long-lived assistant sessions. Technically, Cont3xt exposes four stdio tools—memory_upsert, search_memory, context_pack, and health_ping—returning a uniform JSON envelope for easy integration. It’s a Python 3.11+ console app (virtual-context-mcp) that creates ./data/memory.db, supports env/YAML configuration (default CONTEXT_MAX_TOKENS=12000, chunk size 3200, 500-token buffer), and packs context most-recent-first up to the budget with strict truncation (returns BUDGET_TOO_SMALL if nothing fits). Search is a recency-biased substring lookup over SQLite chunks; optional Qdrant/Neo4j backends exist but are disabled in the MVP. For agent builders this is significant: it provides an auditable, token-aware retriever/packer for long-context agent loops (search → pack → plan → act → upsert) without cloud dependencies, speeding local experiments around memory, retrieval policies, and agent orchestration.