Check if the current webpage displays a CAPTCHA, such as reCAPTCHA, hCaptcha, Turnstile, GeeTest, or FunCaptcha, so you can handle the verification challenge.
Check whether the current page shows a CAPTCHA (recaptcha/hcaptcha/turnstile/geetest/funcaptcha)
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
v2.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden. 'Check whether' appropriately implies a non-mutating read operation, but it does not explicitly reveal whether the check waits for a CAPTCHA to appear, what happens if no page is loaded, or what the return value looks like. The provider list adds useful scope, but timing and response behavior remain implicit.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single sentence that front-loads the action and resource, then efficiently lists the supported CAPTCHA types. There is no redundancy or filler; every word contributes to understanding.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a zero-parameter detection tool, the core purpose is present and understandable. However, since there is no output schema, the description should clarify what the call returns (e.g., a boolean, provider name) and whether it is an immediate snapshot or a waiting check. The missing return-value and timing details leave the agent with uncertainty about how to consume the result.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The tool takes zero parameters and the schema properties are empty, so there are no parameter semantics to document. The description's mention of supported CAPTCHA providers is extra scope context rather than parameter documentation; the baseline for 0-parameter tools applies.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description uses a specific verb ('Check whether') and resource ('current page shows a CAPTCHA'), and enumerates the supported provider types (recaptcha/hcaptcha/turnstile/geetest/funcaptcha). It is clear about the tool's core function, though it does not explicitly contrast with the sibling tool wait_for_captcha.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
No guidance is given about when to call this tool versus alternatives like wait_for_captcha or other page-state tools. The description does not state whether it should be used after page load, whether it returns immediately, or under what conditions the sibling wait_for_captcha would be preferred.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.