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

Beyond the readOnlyHint/openWorldHint annotations, the description discloses the mechanism (URLs discovered from the site's sitemap, pages read concurrently), the return payload (Markdown citations plus page text including live product variants), and a hard behavioral guardrail ('Never guess paths'). No behavior is left for the agent to infer.

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?

Front-loaded with the selection claim, then mechanism, then return format, then guardrails. Every sentence adds information the agent needs (routing, output expectations, anti-hallucination rule) with 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 2-parameter, read-only, no-output-schema tool, the description covers purpose, mechanism, and return shape well enough to call it correctly. The gaps are minor: no explanation of 'pages_per_query' and no indication of what happens when a query matches nothing.

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 0%, so the description must carry parameter meaning; it does explain 'queries' well ('one short page-title/topic query per item'). However, 'pages_per_query' is never mentioned, leaving the agent to discover the 1-3 depth control on its own.

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 (research/compare) and resource (multiple pages on sitemcp.dev), plus scope ('several topics', 'concurrently in one call'). The contrast with 'separate search/read calls' implicitly separates it from siblings search_site and read_page, so an agent can pick it without opening schemas.

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?

'Best tool for comparing or researching several topics' establishes the selection condition, and 'No separate search/read calls are needed if the requested facts are present' rules out chaining search_site + read_page. It never explicitly names the sibling to use for a single page, so the alternative routing is only implied.

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