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

No annotations are supplied, so the description carries the full burden. It does add genuine value by disclosing the credit cost (2 credits) and the breadth of the returned report, and "check" implies a read-only operation. It stops short of describing failure modes: no word on timeouts, unreachable URLs, JS-rendered pages, or whether redirects are followed or merely reported.

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?

One front-loaded sentence: purpose first, then the enumerated checklist, then cost in parentheses. The long comma list of checks is bulky but every item informs the agent about coverage. Minor cost: the sentence is dense for a single-line description.

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 one-parameter tool with no output schema, the enumeration of inspected elements effectively substitutes for a return-value description, and the cost note covers billing behavior. What remains thin is operational context — expected latency, error handling, and how the "list of issues" is structured.

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?

There is a single `url` parameter and schema coverage is reported at 100%, so the baseline is 3. The description only restates that the input is "a URL" of the page being checked; it adds no constraints on format (scheme required? absolute only?), query strings, or authenticated pages.

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 ("On-page SEO check of a URL") and then enumerates exactly what is inspected: title, canonical, robots, hreflang, Open Graph, structured data, headings, alt text, redirects, word count, issues. An agent can distinguish this from sibling checkers such as domain_check, ssl_check or vuln_check because the scope is explicitly on-page content rather than domain/DNS/security posture.

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 is implied by the scope phrase "On-page SEO check" — an agent can infer this is the tool for auditing a page's SEO metadata. However, there is no explicit when-to-use/when-not guidance, no mention of alternatives (domain_check, read_url, ssl_check) and no note on prerequisites such as whether the URL must be publicly reachable.

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