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

Annotations already declare readOnly, idempotent, non-destructive and open-world behavior, so the safety profile is covered. The description adds two pieces of non-redundant context: that no page content is fetched, and that a free SnoopScan API key is required — an auth prerequisite the 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 short, front-loaded sentences with no filler; the core behavior leads and the auth note trails. Slightly tighter phrasing could merge the second and third sentences, but nothing is wasted.

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?

An output schema exists, so return values need no explanation, and the auth requirement is stated. However, for a 3-parameter tool with zero schema description coverage, leaving 'limit' and 'search' entirely undefined makes the definition incomplete for correct invocation.

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% across three parameters, so the description carries the full burden — and it documents none of them. 'limit' and 'search' are never mentioned, and their purpose (result cap, URL filtering) must be guessed from the bare property names.

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: 'List the URLs on a website without fetching page content.' The clause 'without fetching page content' implicitly separates it from scrape/crawl, though it never names a sibling tool explicitly, so an agent still has to infer the contrast.

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?

'Use it to see a site's structure before choosing which pages to scrape' gives a concrete when-to-use scenario. It stops short of naming an alternative tool or stating when this is the wrong choice (e.g., when you already need page content).

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