captcha.cc Human Verification
REMOTE · CAPTCHA.CC · SCANNED SEP 20
Human verification CAPTCHA with visual and selective-listening audio challenges.
Available components
How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. How we score → Why this is hard to score →
Endpoint Security63
- The endpoint's TLS certificate is valid, in date, and uses a strong key. View diagnostics → Pass
- No authorisation is required to call this server. Every tool declares its destructiveHint and none is destructive, so open access doesn't expose one. See how to fix → View diagnostics → Partial
- HTTPS check failed: the endpoint is reachable over plaintext HTTP. See how to fix → View diagnostics → Fail
- HSTS check failed: the Strict-Transport-Security header is absent. See how to fix → View diagnostics → Fail
- DNSSEC check failed: this domain isn't protected by DNSSEC. See how to fix → View diagnostics → Fail
Transport & Reachability100
- Verified streamable-http transport via a live MCP handshake. View diagnostics → Pass
Schema Quality & AI Usability82
- 100% of prompts and resources have a non-trivial description (not blank, and not just the item's name).Pass
- AI-judged instruction clarity (good).Pass
- Tool/resource definitions use about 222 tokens (~55/item across 4 items; 3 tools + 1 resources), lean.Pass
- Usage-examples check failed: none of the tools include examples. See how to fix → Fail
Stability & Change Management100
- No destabilizing schema changes in the last 30 days.Pass
Tool Coverage92
- 100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
- 75% of tool parameters carry a description.Partial
Tool Safety100
- No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.Pass
- We read all 3 captured tool definition(s), and no name or description among them implies an irreversible operation.Pass
- An AI judge read all 4 captured unit(s) of tool text and found none that tries to manipulate the model reading it.Pass
Capabilities100
- Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.Pass
How do I install the captcha.cc Human Verification MCP server?
captcha.cc Human Verification is a hosted endpoint at https://captcha.cc/mcp, so there is nothing to install locally. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.
remote · captcha.cc
claude mcp add --transport http cc-captcha-captchacc 'https://captcha.cc/mcp'
{
"mcpServers": {
"cc-captcha-captchacc": {
"url": "https://captcha.cc/mcp"
}
}
} {
"servers": {
"cc-captcha-captchacc": {
"type": "http",
"url": "https://captcha.cc/mcp"
}
}
} [mcp_servers.cc-captcha-captchacc] url = "https://captcha.cc/mcp"
{
"$schema": "https://opencode.ai/config.json",
"mcp": {
"cc-captcha-captchacc": {
"type": "remote",
"url": "https://captcha.cc/mcp",
"enabled": true
}
}
} openclaw mcp add cc-captcha-captchacc --url 'https://captcha.cc/mcp' --transport streamable-http
mcp_servers:
cc-captcha-captchacc:
url: "https://captcha.cc/mcp" {
"McpServers": {
"cc-captcha-captchacc": {
"Transport": "http",
"Url": "https://captcha.cc/mcp"
}
}
} assistant mcp add cc-captcha-captchacc -t streamable-http -u 'https://captcha.cc/mcp'
{
"mcpServers": {
"cc-captcha-captchacc": {
"type": "http",
"url": "https://captcha.cc/mcp"
}
}
} The mcpServers block is a cross-client convention. Remote transports vary, so check your client's docs.
Every change we have recorded for this component, newest first. Security-relevant changes are always shown. ▲ marks a change for the better, ▼ a change for the worse; unmarked changes are neutral.
- 26 Aug 26 0
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
- 25 Aug 26 +1
- Stability: 0.97 → pass security
- 23 Aug 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 90 to 93. That category is still filling its 30-day observation window: 27 days of observed history at the previous scan, 28 at this one. The score rises as the window fills, whether or not the server changes.
- 11 Aug 26 0
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
- 31 Jul 26 0
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
- 30 Jul 26 0
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
- 27 Jul 26 0
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
- 26 Jul 26 0
First indexed and scored.
Diagnostic detail from the automated scan of this channel: what the scanner observed at each step, so you can see exactly where a check passed or failed. It is informational only and never changes the trust score.
Captured 20 Sept 2026 · Probed https://captcha.cc/mcp
TLS valid
Negotiated TLS 1.3 with TLS_AES_128_GCM_SHA256 .
| Subject | Issuer | Valid from | Valid until | Key | Signature | Serial |
|---|---|---|---|---|---|---|
| CN=captcha.cc | CN=YE1,O=Let's Encrypt,C=US | 17 Sept 2026 | 16 Dec 2026 | ECDSA 256 | ECDSA-SHA384 | 6b15cda6d25191a1c023e3c78a98e4045a4 |
| SANs: *.captcha.cc, captcha.cc | ||||||
| CN=YE1,O=Let's Encrypt,C=US (CA) | CN=Root YE,O=ISRG,C=US | 3 Sept 2025 | 2 Sept 2028 | ECDSA 384 | ECDSA-SHA384 | 5ddd70dd31f801c85c186a7a04b80afe |
| CN=Root YE,O=ISRG,C=US (CA) | CN=ISRG Root X2,O=Internet Security Research Group,C=US | 13 May 2026 | 2 Sept 2032 | ECDSA 384 | ECDSA-SHA384 | 872165fc34b6e5fba8add5b3705fb53a |
| CN=ISRG Root X2,O=Internet Security Research Group,C=US (CA) | CN=ISRG Root X1,O=Internet Security Research Group,C=US | 13 May 2026 | 2 Sept 2032 | ECDSA 384 | SHA256-RSA | 6c8f1dc727c7117f7baf853ac980f9cd |
Background: What to check on a remote MCP endpoint →
DNSSEC insecure
Validation of captcha.cc. — Not signed
| Zone | DS | Keys | Algorithms | Outcome |
|---|---|---|---|---|
| . | trust_anchor | 20326, 38696 | 8, 8 | Verified |
| cc. | present | 12593 | 13 | Verified |
| captcha.cc. | absent | Unsigned (proven) parent-signed NSEC/NSEC3 proves an unsigned delegation |
Authentication No authorisation required
The endpoint answered without asking for a token. Anyone who knows the URL can reach it.
| Result | No authorisation required |
|---|---|
| HTTP status | 200 |
Background: How OAuth 2.1 works in the 2026 MCP spec →
Transports 2 probes
| Transport | URL | Outcome | Status | Location |
|---|---|---|---|---|
| streamable-http | https://captcha.cc/mcp | Verified | 200 | |
| http (plaintext) | http://captcha.cc/mcp | Served over HTTP | 200 |
The tools this component advertises to a client, with an estimated token cost for each. Expand a tool to see its parameters and schema. The per-tool counts are indicative and are not scored directly; the schema's total context footprint is one signal in Schema Quality & AI Usability. A tool's description is untrusted text the model reads on every call, which is what makes this list a security surface and not just an inventory: how tool poisoning works →
create_challenge Create Challenge ~59
Create a live captcha.cc challenge for a site key and allowed hostname. Useful for smoke tests and integration checks.
| Name | Type | Req | Description |
|---|---|---|---|
| hostname | string | yes | Hostname configured on the captcha.cc site. |
| site_key | string | yes | Public captcha.cc site key. |
No output schema declared.
No examples provided.
make_siteverify_request Make Siteverify Request ~45
Return a server-side fetch example for redeeming a captcha.cc proof token exactly once.
| Name | Type | Req | Description |
|---|---|---|---|
| proof_token_expression | string | – | – |
| secret_env_var | string | – | – |
No output schema declared.
No examples provided.
make_widget_snippet Make Widget Snippet ~96
Return a minimal browser SDK snippet for mounting captcha.cc and submitting the proof token to an application endpoint.
| Name | Type | Req | Description |
|---|---|---|---|
| element_id | string | – | DOM element id where the widget should mount. |
| form_id | string | – | Form id to attach submit handling to. |
| site_key | string | yes | Public captcha.cc site key, for example pk_live_xxx. |
| submit_path | string | – | Application endpoint that receives the proof token. |
No output schema declared.
No examples provided.
What is the captcha.cc Human Verification MCP server?
captcha.cc Human Verification is an MCP server listed in the public MCP registry as cc.captcha/captchacc. Human verification CAPTCHA with visual and selective-listening audio challenges. This page covers its hosted endpoint (https://captcha.cc/mcp).
Is the captcha.cc Human Verification MCP server safe to use?
captcha.cc Human Verification scores 81 out of 100 on VerifyMCP. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.
What tools does the captcha.cc Human Verification MCP server expose?
captcha.cc Human Verification exposes 3 tools: make_widget_snippet, make_siteverify_request, create_challenge. Their descriptions and schemas cost roughly 200 tokens of context every time the server is loaded.
Does the captcha.cc Human Verification MCP server require authentication?
No. We connected to captcha.cc Human Verification without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.
Is the captcha.cc Human Verification MCP server still maintained?
captcha.cc Human Verification is still listed as active in the MCP registry. We last reached this channel on 20 September 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.