| name | cloak-fetch |
| description | 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 |
| metadata | {"author":"Agents365-ai"} |
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, <title>blocked</title>, dd-cookie / datadome cookie, <head>...captcha-delivery.com, geo-block style 403 with empty body |
| Akamai Bot Manager | Access Denied with Reference #18. (long hex.epoch.hex) ID, <TITLE>Access Denied</TITLE> + Akamai <HTML><HEAD> 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), <title>Human Verification</title> |
| 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 | <head> containing ips.js, x-kpsdk-cd / x-kpsdk-cr response headers, 429 with empty body + kasada reference |
| AWS WAF | Request blocked + , cookie, body referencing |
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:
<SKILL_DIR>/cloak_fetch.sh "<URL>"
Where <SKILL_DIR> 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:
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"
- Agent tries
WebFetch — gets HTTP 403 Forbidden.
- Agent recognises the 403 → invokes this skill:
~/.claude/skills/cloak-fetch/cloak_fetch.sh \
"https://www.science.org/content/page/information-authors-research-articles"
- ~25 s later, ~26 KB of clean markdown lands on stdout.
- Agent answers the user from the markdown — no need to mention the
underlying fetch took two attempts.
Related
- cloakFetch hook — 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 — distributed by TomeVault.
