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

Annotations already declare readOnlyHint, openWorldHint, and destructiveHint, so safety is covered. The description adds real behavior beyond that: it enumerates which checks run, discloses the output shape (0-100 score, letter grade, per-gap fix), and notes the tool is free, which is cost information annotations do not carry. With no output schema, that return-shape disclosure is doing genuine work.

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 core purpose and followed by the scope of checks and the return format. Every clause is information-bearing, though the parenthetical list of engines and the trailing 'Free.' are slightly list-heavy for the length.

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 inspection tool with no output schema, the description supplies the purpose, the checked dimensions, and the return shape, which is exactly what an agent needs to invoke it and interpret results. Nothing material 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?

Schema description coverage is 100% and the schema already gives the accepted formats (example.com or https://example.com). The description adds no syntax, normalization, or defaulting detail beyond 'the website to check', so the baseline of 3 for fully documented parameters is appropriate.

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 gives a specific verb ('check whether a website is visible') plus the resource and the exact dimensions examined (crawler access, JSON-LD, title/meta, Open Graph, sitemap, llms.txt). That is far more concrete than a restatement of the name. It stops short of explicitly differentiating from the sibling check_agent_readiness, which is the main thing keeping it from a 5.

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?

There is no when-to-use statement, no prerequisites, and no named alternative or exclusion. An agent must infer from the phrasing that this is the 'website-side' check rather than an agent-side check, and nothing tells it when it would call check_agent_readiness instead.

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