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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=true, covering the safety profile. The description adds one behavioral detail: the response follows the SimilarWeb v5 envelope (meta + data). This is useful context beyond the annotations, but it does not disclose rate limits, auth, or other operational traits. Given the strong annotation coverage, a 3 is appropriate.

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?

The description is very short (two sentences), so it is concise, but the first sentence 'Landing Pages' is redundant with the title and adds no value. The second sentence about the envelope is the only useful content. It is front-loaded but under-specified; it is not bloated, but it also doesn't earn all its space.

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?

With 10 parameters, 3 enums, and a clear need to know what data is returned, the description is grossly incomplete. It fails to state the tool's purpose, which is fundamental. Even though an output schema exists, the agent cannot correctly select this tool because it doesn't know what it does. The description is inadequate for a tool of this complexity.

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%, so every parameter already has a description in the schema. The tool description adds no extra meaning about parameters – it doesn't mention any of them or clarify their semantics beyond what the schema provides. Baseline 3 is correct.

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 simply repeats the title 'Landing Pages' without stating the function. It does not specify that the tool returns landing page data for a domain, and the only additional detail is about the response envelope, which is about format, not purpose. This is a tautology that gives an agent no clue what the tool actually does.

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 guidance on when to use this tool versus alternatives like get_similarweb_popular_pages or other SimilarWeb endpoints. No context is given about use cases, prerequisites, or why an agent would choose this over siblings. The description provides zero directional help.

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