This repository implements an MCP (Model Context Protocol) server that bridges AI assistants with SearXNG, a privacy-respecting metasearch engine. It exposes four primary tools: `searxng_web_search` for web queries, `searxng_search_suggestions` for autocomplete, `searxng_instance_info` for capability discovery, and `web_url_read` for fetching and converting web pages to markdown. The server runs in two transport modes: STDIO (default) for simple MCP integration, and HTTP for stateful/stateless remote access with optional OAuth and static bearer authentication. The architecture is modular and security-focused. Core modules include a proxy layer with per-type agent selection, SSRF protection via private IP blocking and DNS rebinding detection, a browser solver chain (FlareSolverr/Byparr) for challenge solving, worker-threaded PDF extraction, and multi-instance failover/fanout for SearXNG replicas. All credential-bearing output (logs, errors, MCP resources) is redacted by a centralized sanitizer. Extensive environment-variable configuration (~40+ knobs) controls caching, timeouts, rate limiting, TLS, and result formatting. Highlights include a strict integer parser that rejects unsafe or malformed values, an LFU cache with age tie-breakers and configurable TTL, and a comprehensive URL security module covering both IPv4 and IPv6 private ranges. The test suite achieves over 90% line coverage and includes integration, unit, fuzz, and e2e tests, with documentation tests that verify README and configuration docs match source contracts. The project is actively maintained with frequent releases, pinned dependencies, and a verification gate that enforces zero-vulnerability audits before publishing.