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

Annotations already cover readOnly, idempotent, openWorld and non-destructive, so the safety profile is handled elsewhere. The description adds genuinely new behavioral context the annotations cannot carry: an Authorization: Bearer key requirement, a paid tier, and a price point, which an agent needs before attempting a call. It stops short of describing rate limits or failure behavior per URL.

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?

Two sentences, front-loaded with the capability and the returned fields, then the access precondition. The raw URL plus "$15 per 3 months" is slightly bulky but earns its place as a gating fact; there is no filler.

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 single-parameter read tool with no output schema, the description compensates well by enumerating the returned data points and stating the auth requirement. Nothing essential to deciding whether and how to call it is missing.

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?

With one parameter at 100% schema description coverage, the schema already documents urls as "Public URLs" with minItems 1 and maxItems 10. The description's "up to 10 URLs in one call" merely restates the maxItems constraint rather than adding format, normalization, or validity guidance beyond it.

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 ("Quick on-page check of up to 10 URLs in one call") and enumerates exactly what is inspected: HTTP status, title, meta description, H1, canonical, noindex, lang, Open Graph, thin content. The "bulk / up to 10 URLs" framing implicitly separates it from a single-URL seo_check, but it never names that sibling, so the differentiation is left to inference.

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?

The word "Quick" and the bulk framing imply when to reach for this, and the paid-key requirement is a real gating prerequisite. However, there is no explicit statement of when to use this versus seo_check, full_site_crawl, or security_headers_check, and no exclusions (e.g., large sites, private URLs) are given.

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