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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds real value beyond that by disclosing the graded output ('Returns an A-F grade') and the enumerated audit surface, which matters because there is no output schema to convey the return shape.

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?

A single sentence that front-loads the action and resource, then lists the audit scope. No filler, no restating of the tool name, and the return of an A-F grade is tacked on efficiently at the end.

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 read-only auditing tool with no output schema, the description covers both what is inspected and the shape of the result (a letter grade), which is the main thing an agent needs. Minor gaps remain around accessibility/crawlability requirements of the target URL and expected runtime, but nothing critical 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?

Only one parameter and the schema already documents it at 100% coverage ('Full https URL to check'), so the baseline is 3. The description adds nothing about URL requirements — e.g. whether the page must be publicly crawlable, whether redirects are followed, or how non-https or malformed URLs are handled.

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 action (on-page SEO audit) on a specific resource (a URL) and enumerates the exact check categories covered: title, meta description, H1, canonical, indexability, Open Graph, structured data, image alt coverage, sitemap. This clearly separates it from siblings like check_security_headers or check_ssl.

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 name and description — audit a single page's on-page SEO — but there is no explicit statement of when to prefer this over check_ai_visibility, scan_website, or scan_local_code, nor any exclusions or prerequisites. A reader can infer intent but gets no routing guidance.

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