Nab

What MikkoParkkola/nab does

MikkoParkkola/nab combines web retrieval, local media analysis, and URL monitoring in one Rust binary. Web pages are returned as clean Markdown shaped for LLM context rather than as raw HTML. Fetching can use browser cookies, focused extraction, readability processing, token budgets, and sessions. The server also supports form submission with CSRF handling and automatic field extraction.

Media analysis runs locally. Audio and video can be transcribed and diarized, with multilingual support, word-level timestamps, and model choices that include FluidAudio, Sherpa-ONNX, Whisper, and optional Qwen3-ASR coverage for Chinese, Japanese, Korean, and Vietnamese. Apple Vision OCR is available on macOS.

URL watches use MCP resources to notify clients about changes. The watcher supports conditional requests, semantic differences, adaptive polling, and RSS-style monitoring for arbitrary web pages.

How it works

The nab-mcp executable exposes the MCP interface over stdio and Streamable HTTP. Fetching uses HTTP/2 and HTTP/3 capabilities, with optional JavaScript rendering through a configured Chrome DevTools Protocol WebSocket endpoint. Browser rendering is explicitly enabled rather than automatically started by ordinary fetches.

All processing is local by default, and no API keys are required for the basic setup. Browser cookies can be read from supported browsers, while 1Password integration can look up credentials and perform logins that include TOTP or MFA. A fingerprint tool can create Chrome, Firefox, or Safari profiles.

Fetched content is also checked by local prompt-injection defenses. Hidden machine-directed markup is surfaced or removed, and YARA-X signatures can redact suspicious prompt-injection, exfiltration, secret-leak, or obfuscation content. The default behavior is to redact matched sections; refusal and audited bypass options are available through environment variables.

Setup and configuration

Install the binary with Homebrew on macOS, cargo binstall, or a pre-built binary from the GitHub releases. The release artifacts include both the nab command-line tool and the nab-mcp server for macOS, Linux, and Windows targets. A Rust toolchain is not needed when using a pre-built binary.

Configure an MCP client to launch nab-mcp for stdio transport, or use its Streamable HTTP endpoint. The project specifically describes use with Claude Code, Cursor, Windsurf, and VS Code. Download inference models separately with the nab models fetch command; available model families include FluidAudio, Sherpa-ONNX, and Whisper.

Tools and capabilities

• fetch retrieves one URL as clean Markdown with cookies, focus, token-budget, and session controls.
• fetch_batch retrieves multiple URLs in parallel.
• submit sends web forms with CSRF handling and smart field extraction.
• login performs website login using 1Password credentials, including TOTP or MFA.
• auth_lookup finds 1Password credentials for a URL without returning the password.
• fingerprint generates browser fingerprint profiles for Chrome, Firefox, or Safari.
• analyze transcribes and diarizes audio or video with multilingual ASR.
• watch_create, watch_list, and watch_remove manage URL monitors and their MCP resource notifications.
• validate exercises protocol, transport, TLS, and 1Password-related checks against real sites; benchmark measures repeated URL fetches with minimum, average, and maximum timings.

The server also exposes MCP prompts, resources, structured logging, sampling, roots, and elicitation capabilities. Its security modules are free for personal and non-commercial use under PolyForm Noncommercial 1.0.0; commercial or business use requires a commercial license.