nab

name	nab
version	2026.05.26
effort	low
triggers	fetch|fetch url|url to markdown|read this url|grab this page|scrape|authenticated fetch|behind login|paywall|paywalled|cookies|brave cookies|1password|totp|mfa|sso|internal dashboard|google workspace doc|saas page|webfetch|web fetch|batch fetch|form submit|csrf|clean markdown|token budget
description	How and WHY to use nab — the preferred URL->markdown microfetch tool for agents. Decision: nab (auth + cookies + anti-bot, ~50ms, LLM-shaped markdown) > jina (clean MD fallback) > NEVER WebFetch (~50K tokens/call, ~25x waste). Prefer the nab MCP tools (fetch, fetch_batch, submit, login, auth_lookup) when the plugin's nab server is loaded; fall back to the `nab` CLI. Auto-picks for "fetch this URL", "read the page", authenticated / paywalled / SaaS / Google Workspace content, multi-URL batches, and form submits. nab is a fetch tool, NOT a browser.
composes_with	research, url-insight, wayback, ia, oreilly

nab Skill — Auth-Aware URL→Markdown Microfetch

nab is the default way to turn any URL into clean, token-tight markdown — including pages behind cookies, 1Password/TOTP, passkeys, and anti-bot WAFs. It is not a browser: it reads your existing browser session, returns LLM-shaped markdown, and ships nothing else.

Prime directive (Fukasawa — without thought)

URL -> markdown      : nab (MCP fetch) -> nab CLI -> jina (FREE clean MD) -> NEVER WebFetch
authenticated URL    : nab --cookies brave  (existing session)  OR  nab --1password (login + TOTP)
3+ URLs              : nab fetch_batch (MCP)  /  nab fetch --batch file --parallel N (CLI)
form / login flow    : nab submit (CSRF-aware)  /  nab login (1Password auto-login)
WebFetch             : NEVER — ~50K tokens/call (~25x the nab cost in context)

Why nab wins: ~50ms, HTTP/3, real browser-cookie injection, 1Password auto-login with TOTP/MFA, WebAuthn/passkey, fingerprint spoofing, WAF evasion, 12 site providers (official APIs / stable structured data, not broad HTML scraping), BM25-lite query-focused extraction, and a structure-aware token budget. WebFetch dumps raw, unbudgeted HTML into context.

MCP-first, CLI-fallback

Prefer the nab MCP tools when the plugin's nab MCP server is loaded (registered as nab in plugin/.mcp.json; the host surfaces tools as mcp__nab__<tool>). The 12-tool surface includes these load-bearing tools (V — from README.md MCP table):

MCP tool	Use for
fetch	One URL → markdown, with cookies, query focus, token budget, session
fetch_batch	Parallel multi-URL fetch with task-augmented async execution (3+ URLs)
submit	Submit a form with CSRF + smart field extraction
login	1Password auto-login with TOTP support
auth_lookup	Look up 1Password credentials for a URL

Naming note (V — source-verified): the repo registers these under bare names via the derive macro, e.g. #[mcp_tool(name = "fetch")] and #[mcp_tool(name = "auth_lookup")] (src/bin/mcp_server/tools/fetch.rs:39, …/auth.rs:16; full map in …/tools/mod.rs). There is no nab_ prefix anywhere in src/bin/mcp_server/. When surfaced through a host the tools appear server-qualified — mcp__nab__fetch (Claude Code) or nab:fetch (mcp-gateway). The operator's earlier nab_fetch shorthand was a convention, not the wire name. Canonical set: fetch, fetch_batch, submit, login, auth_lookup, analyze, fingerprint, validate, benchmark, watch_create / watch_list / watch_remove.

If the MCP server is unavailable, fall back to the CLI (V — from README.md):

nab fetch <url>                                  # plain fetch → markdown
nab fetch <url> --cookies brave                  # use your existing Brave session
nab fetch <url> --1password                      # 1Password login (TOTP/MFA supported); alias: --op
nab fetch <url> --batch urls.txt --parallel 8    # batch CLI fetch
nab fetch <url> --format json                    # structured output instead of markdown
nab fetch <url> --render --browser-cdp-url wss://... # JS-heavy SPA via external CDP (opt-in)
nab otp <domain>                                 # pull a one-time code: 1Password TOTP → SMS → email

--cookies accepts: auto, brave, chrome, firefox, safari, edge, none (V).

TOTP/MFA (V — source-verified): two paths exist. (1) Inline — login / --1password handle TOTP during auto-login (README: "1Password auto-login with TOTP support"). (2) Standalone — nab otp <domain> does exist as a CLI subcommand (src/main.rs:361 Otp { domain } → src/cmd/otp.rs cmd_otp). It resolves a one-time code by searching, in order: 1Password TOTP → SMS via Beeper → Email via Gmail. Use nab otp <domain> to pull a code out-of-band; use login / --1password for an end-to-end authenticated flow.

When to use which (decision table)

Situation	Reach for	Conf
Public page, just need the text	fetch (MCP) / nab fetch <url>	V
Page where you are already signed in (browser)	fetch + cookies / --cookies brave	V
SaaS / internal dashboard / paywalled research	--cookies <browser> or --1password	V
Google Workspace doc you can open in your browser	--cookies brave on the doc URL	V
3+ URLs / a research fan-out	fetch_batch / --batch file --parallel N	V
Submitting a form (search, login form, action)	submit (CSRF-aware)	V
Need credentials resolved for a URL before fetch	auth_lookup	V
JS-only SPA returning thin content	--render + external CDP (opt-in)	V
Need structured fields, not prose	--format json	V

Cross-links — siblings in this plugin

nab is the fetch primitive; these bundled skills layer intent on top of it (all V — dirs exist in plugin/skills/):

• research — academic/literature orchestration (arxiv, semantic_scholar, openalex, …). Use for "find papers on X", prior art, SOTA maps. It still routes URL reads through nab.
• url-insight — URL triage + ROI scoring before you spend a fetch.
• wayback — Wayback Machine / CDX: lock durable evidence, fetch a prior version, then hand the archived URL to nab for clean markdown.
• ia — Internet Archive item metadata, uploads, downloads, collection search.
• oreilly — practitioner-grade books/chapters for production/operator guidance.

Composition pattern: url-insight (is it worth it?) → nab fetch/fetch_batch (get it) → wayback (pin it) → research/oreilly (widen it). The /nab command wires these together.

Anti-patterns (NEVER)

Anti-pattern	Do instead
WebFetch a URL	nab (MCP) → nab CLI → jina; ~25x cheaper in tokens
Pasting raw HTML into context when markdown suffices	let nab return budgeted markdown (fetch)
Looping single fetch calls over a URL list	fetch_batch / --batch --parallel
NAB_YARA_BYPASS=1 for convenience	leave the YARA-X fetch guard ON (audited bypass only)
Treating nab as public-web only	use --cookies / --1password for authed reach
Calling / describing nab as a "browser" or "engine"	it reads your browser's cookies; it is a fetch tool
Scraping a site nab already has a provider for	nab uses official APIs / structured data for 12 sites

Security note

nab scans fetched bodies with a fetch-time YARA-X guard by default (prompt-injection / exfil / secret signatures). Keep it on. NAB_YARA_BYPASS=1 is an audited emergency operator escape hatch only; NAB_YARA_ACTION=refuse blocks instead of redacting matched sections (V — CLAUDE.md).

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Confidence: V = verified in nab README.md / CLAUDE.md / plugin/.mcp.json (v0.10.3) or source (src/main.rs, src/cmd/otp.rs, src/bin/mcp_server/tools/) | I = schema/convention argument | A = operator-config assertion not confirmed in this repo. Both prior open flags (nab otp existence, MCP tool naming) are now source-verified V (2026-05-26).

2026.05.26 | closes the "no skill teaches nab itself" gap in the nab plugin