# Cloak Fetch > Use as a fallback when a web page won't load via WebFetch, curl, or any HTTP client because it's behind anti-bot protection — Cloudflare, DataDome, Akamai Bot Manager, PerimeterX/HUMAN, Imperva/Incapsula, F5/Distil, Kasada, AWS WAF, Sucuri, or generic WAF/CDN screening — and returns 403/429/"Just a moment"/"Access Denied"/"Pardon Our Interruption"/"Please verify you are a human"/"Incapsula incident"/"Sucuri WebSite Firewall"/"Reference - Skill: `tomevault-io/cloak-fetch` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/cloak-fetch` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/cloak-fetch/raw - Safety review: pending (external: skill-scanner PASS, skillspector PASS) - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: DevOps & Infra - Author: tomevault-io (https://skillmd.com/u/tomevault-io) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tomevault-io/cloak-fetch --- # cloak-fetch — bot-protection / WAF fetch fallback When a normal HTTP fetcher fails because the target site uses bot protection or WAF screening, route the same URL through CloakBrowser (a real Chromium with anti-bot patches at the C++ level and a genuine TLS/JA3 fingerprint) and return clean markdown via trafilatura. The agent never has to tell the user "the page is unfetchable" — it can try this skill first. The underlying engine doesn't care which vendor is blocking the request — Cloudflare, DataDome, Akamai, PerimeterX, Imperva, Distil, Kasada, AWS WAF, or a no-name WAF rule. They all eventually let a real browser through, and CloakBrowser is a real browser. ## When to trigger Use **immediately** after any of these symptoms from a recent fetch tool call: | Symptom in tool output | Likely cause | |---|---| | `HTTP 403`, `403 Forbidden`, `HTTP 429` | Bot protection or rate-limit block | | Empty body / a few hundred bytes of nothing on a content-rich URL | Silent WAF / TLS-fingerprint reject | | Page rendered as a near-empty shell with a JS challenge script | SPA-only page or anti-bot challenge | | `Resource was not loaded`, `net::ERR_HTTP2_PROTOCOL_ERROR` | Upstream blocked the fetch handshake | | `Access denied`, `Blocked`, `You don't have permission` | Generic WAF / bot detection | ### Vendor-specific signatures If the failure string roughly matches one of these, **it's a CloakBrowser case** — don't waste another round-trip on a plain HTTP client: | Vendor | Telltale strings / headers | |---|---| | **Cloudflare** | `Just a moment...`, `Enable JavaScript and cookies to continue`, `cf-ray:` header, `__cf_bm` cookie, `Attention Required! \| Cloudflare`, `Sorry, you have been blocked` | | **DataDome** | `blocked by DataDome`, `blocked`, `dd-cookie` / `datadome` cookie, `...captcha-delivery.com`, geo-block style 403 with empty body | | **Akamai Bot Manager** | `Access Denied` with `Reference #18.` (long hex.epoch.hex) ID, `Access Denied` + Akamai `` boilerplate, `Pragma: akamai-x-cache`, `akamai-bot-manager` cookie | | **PerimeterX / HUMAN** | `Please verify you are a human`, `Access to this page has been denied because we believe you are using automation tools`, `_px*` cookies (`_pxhd`, `_px3`), `Human Verification` | | **Imperva / Incapsula** | `Incapsula incident ID:`, `Request unsuccessful. Incapsula incident ID`, `_Incapsula_Resource`, `visid_incap_*` cookie, `X-Iinfo` header | | **F5 / Distil** | `Pardon Our Interruption`, `As you were browsing something about your browser made us think you were a bot`, `distil_r_captcha`, `D_RID` cookie | | **Kasada** | `` containing `ips.js`, `x-kpsdk-cd` / `x-kpsdk-cr` response headers, `429` with empty body + `kasada` reference | | **AWS WAF** | `Request blocked` + ``, `awswaf` cookie, body referencing `aws-waf-token` | | **Sucuri** | `Sucuri WebSite Firewall - Access Denied`, `Sucuri WebSite Firewall - CloudProxy`, `X-Sucuri-ID` / `X-Sucuri-Cache` header, `sucuri-cf-id` cookie (very common on self-hosted WordPress) | | **reCAPTCHA / hCaptcha passive triggers** | Interstitial that *displays without user interaction* — page replaced with `g-recaptcha`/`h-captcha` div and no real content. (See "When NOT to trigger" for interactive checkbox/slider cases.) | | **TLS / JA3 fingerprint reject** | Connection drops, empty body, `ERR_HTTP2_PROTOCOL_ERROR`, `SSL_ERROR_ZERO_RETURN` on a site that loads fine in a normal browser | Also trigger preemptively when the user asks to fetch a page on a domain known to live behind one of these stacks — publishers (science.org, nature.com, sciencedirect.com, jstor.org), news (nytimes.com, bloomberg.com, ft.com, wsj.com), retail (nike.com, adidas.com, sephora.com), travel (kayak.com, southwest.com), financial (most broker portals). Going straight to this skill avoids a guaranteed-to-fail plain-HTTP round trip. ## When NOT to trigger | Symptom | Why this skill won't help | |---|---| | `404 Not Found` | Page genuinely doesn't exist | | `500 Internal Server Error` | Origin is broken, not blocking you | | `401 Unauthorized` / login wall | Credentials needed — CloakBrowser does not carry them | | Plain network error (DNS, connection refused, no route to host) | Network unreachable, not a bot block | | **Interactive** captcha — slider, image-grid (reCAPTCHA "select all crosswalks"), Cloudflare Turnstile **checkbox** that requires a click, hCaptcha challenge | Needs a human or a paid solver service. CloakBrowser passes *passive* fingerprint checks but does not solve human-interaction challenges. | | Geo-block where your IP's country is the actual reason (`This content is not available in your region`) | CloakBrowser uses the same IP — proxy/VPN is the fix, not a different browser | | Site requires a session cookie, OAuth, or signed URL | No credential plumbing — fetch the auth artifact first via the proper channel | | The normal fetcher already succeeded | No need to re-fetch | In these cases, report the actual failure to the user instead of masking it. ## How to invoke One command — the wrapper picks the right Python, runs the headless browser, extracts the main content with trafilatura, and writes clean markdown to stdout: ```bash /cloak_fetch.sh "" ``` Where `` is wherever this skill is installed. Common locations: - Claude Code: `~/.claude/skills/cloak-fetch` - OpenClaw: `~/.openclaw/skills/cloak-fetch` - Codex: `~/.codex/skills/cloak-fetch` - Project-local: `.claude/skills/cloak-fetch` or `skills/cloak-fetch` A portable invocation that finds the skill across these locations: ```bash for d in \ "$HOME/.claude/skills/cloak-fetch" \ "$HOME/.openclaw/skills/cloak-fetch" \ "$HOME/.codex/skills/cloak-fetch" \ ".claude/skills/cloak-fetch" \ "skills/cloak-fetch"; do if [ -x "$d/cloak_fetch.sh" ]; then SKILL_DIR="$d"; break fi done "$SKILL_DIR/cloak_fetch.sh" "https://www.science.org/content/page/information-authors-research-articles" ``` The wrapper streams clean markdown on stdout. Save to a file with `> out.md` or pipe directly into further processing. ## Behavior - **Headless by default** — no browser window opens. - **Latency:** ~20–40 s per call (browser launch + page render + content settle). - **Output:** clean markdown via trafilatura. Page chrome, navigation, ads, and cookie banners stripped. Headings, lists, links, and code blocks preserved. When trafilatura can't isolate a main content node, the wrapper falls back to emitting the rendered HTML so the agent still has something to read. - **Failure modes:** exits non-zero with a message on stderr if no cloakbrowser-enabled Python is found, the browser couldn't reach the URL, or CloakBrowser couldn't pass the challenge. Surface the failure honestly to the user — do not fabricate page content. ## Configuration | Env var | Purpose | Default | |---|---|---| | `CLOAKBROWSER_PYTHON` | Path to the Python interpreter with `cloakbrowser` installed | `~/github/CloakBrowser/.venv/bin/python`, falling back to `python3` | For more advanced tuning (headless toggle, content-selector wait list, settle timing), edit `cloak_fetch.py` directly — see comments in that file. ## Example end-to-end User: "Get the authors info from https://www.science.org/content/page/information-authors-research-articles" 1. Agent tries `WebFetch` — gets `HTTP 403 Forbidden`. 2. Agent recognises the 403 → invokes this skill: ```bash ~/.claude/skills/cloak-fetch/cloak_fetch.sh \ "https://www.science.org/content/page/information-authors-research-articles" ``` 3. ~25 s later, ~26 KB of clean markdown lands on stdout. 4. Agent answers the user from the markdown — no need to mention the underlying fetch took two attempts. ## Related - [cloakFetch hook](../../hooks/) — same fallback wired up as a Claude Code `PostToolUse` hook (fully automatic, no agent decision required). Use the hook on Claude Code; use this skill on agents that lack a hook system (Codex, OpenCode, OpenClaw, etc.). --- > Source: [Agents365-ai/cloakFetch](https://github.com/Agents365-ai/cloakFetch) — distributed by [TomeVault](https://tomevault.io).