Check one page

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

The description explicitly says 'Read-only: it only downloads the page', reinforcing and extending the readOnlyHint/idempotentHint annotations. It also discloses the output behavior ('returns what it found and a list of problems in order of importance') and the absence of credential requirements, which annotations do not convey.

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?

Three front-loaded sentences cover purpose, output, auth, and read-only behavior with no filler. Every sentence earns its place.

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 simple one-parameter read-only tool with no output schema, the description is complete: it lists inputs, outputs, access requirements, and side-effect behavior. There is no missing information an agent would need to invoke it correctly.

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 100%, so the URL parameter is already fully documented in the schema. The description confirms the URL should be a public page but adds no new parameter-level detail beyond that baseline.

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 names a specific action ('fetches one public page'), a concrete scope ('one public page the way a search engine does'), and enumerates the exact checks performed (title, meta description, canonical, noindex, robots.txt, H1s, word count, alt text, structured data). This scope clearly separates it from site-level siblings like site_overview and list_sites.

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 context is implicit: use this when you need a per-page SEO/crawlability audit. It also gives a useful prerequisite ('public page', 'without any Google credentials'), but it never explicitly states when to prefer a sibling or when not to use the tool.

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