ScrapeNinja MCP by usefulapi

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description adds useful behavioral context about billing, confirmation, proxy limits, no automatic retries, and untrusted returned content. But it labels the operation 'BILLABLE READ' while annotations declare readOnlyHint=false and destructiveHint=true, which is a direct contradiction under the rubric.

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?

Front-loads the billable warning, then states purpose and constraints in dense, purposeful sentences. There is no filler and the length is appropriate for a billable external render tool.

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?

Covers the key safety context: billing, required confirmation, proxy limitations, retry behavior, and untrusted output. It remains incomplete because block flags and waitForSelector are unexplained, and sibling differentiation is absent.

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?

Schema coverage is 57%; geo, url, confirm, and postWaitTime are documented, while blockMedia, blockImages, and waitForSelector are not. The description clarifies confirm and proxy restrictions but does not compensate for the undocumented parameters.

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?

States a specific verb ('Render') and resource ('one public page') and says it returns HTML. It does not name the sibling scrapeninja_scrape_page or explain how this differs from plain scraping.

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?

Provides constraints such as confirm:true, billing risk, basic proxies, and no premium proxies/custom scripts/headers/cookies/forms. However, it never explicitly says when to use this instead of scrapeninja_scrape_page; the JavaScript-rendering use case is only implied.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Goes well beyond the annotations: it discloses billing exposure, the mandatory confirm:true gate, basic-only proxies, a single attempt with no automatic API retries, and that returned content is untrusted. This also explains why readOnlyHint is false despite the operation being framed as a 'read'. It does not describe failure behavior or the shape of the response, which keeps it off a 5.

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?

Five short sentences, each carrying distinct information, with the billable/confirm warning front-loaded before mechanics. No filler or repetition of the title.

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?

No output schema exists, and the description covers the essentials: what is returned (raw HTML), the cost gate, proxy limitations, and the untrusted-data warning. It is only slightly short on what to expect on failure or partial responses for a single-attempt call.

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?

Schema description coverage is 100%, so url, geo, and confirm are already fully documented in the schema. The description restates proxy and attempt behavior but adds no parameter syntax or constraints beyond what the schema provides, so baseline 3 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?

States a specific verb and resource ('Retrieve one public page's HTML') plus a key delimiter, 'without JavaScript', which implicitly separates it from the render_page sibling. It never names the sibling explicitly, so an agent must infer that render_page is the JS-capable alternative.

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?

Usage context is implied through the 'without JavaScript' qualifier and the confirm requirement, but there is no explicit routing guidance such as 'use scrapeninja_render_page when the page needs JavaScript execution'. The agent has to derive the decision rule on its own.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.