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

The annotations already declare readOnlyHint, openWorld, idempotent, and non-destructive, and the description adds meaningful behavioral detail beyond them: the single-month date bucket, the latest-available-month requirement, country-dependent availability, and the specific error_code 101. This materially helps an agent anticipate failure and avoid invalid calls.

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 compact and mostly dense with the critical date constraint explained efficiently. The opening phrase 'Website Technologies.' is redundant filler, but the remaining sentences earn their place by explaining the envelope and the non-obvious date behavior without unnecessary detail.

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?

The output schema and annotations carry much of the burden, and the description covers the main hidden trap (date range). However, it never explicitly states what the returned technologies data actually represents, and it leaves tool-selection context entirely absent for an agent choosing among other SimilarWeb tools.

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%, which provides a baseline of 3. The description goes beyond the schema by clarifying the relationship between start_date and end_date: they must be the same month, must be the latest available month, may differ by country, and invalid combinations return error_code 101. This is important semantic content the schema does not express.

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 opens by repeating the title 'Website Technologies' but never states an action such as retrieves, lists, or returns the technologies used by a domain. It focuses almost entirely on the response envelope and date constraints, so an agent must infer the tool's purpose from its name rather than from the description.

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 description gives no guidance on when to choose this tool over the many similar get_similarweb_* siblings, nor does it name an alternative. The date constraint is invocation-level guidance, not tool-selection guidance, so an agent deciding between this and similar tools gets no help.

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