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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds genuinely new behavioral facts the annotations cannot convey: results are sorted by site name and are not paginated. It says nothing about result volume or error cases, which keeps it just short of a 5.

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 purpose, then workflow, then return shape and ordering, in four tight sentences. Minor redundancy in enumerating returned fields (identifier, name, tested-page count) that the output schema already exposes, but nothing is padded.

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 prose, yet the description still names the key fields and, more importantly, discloses sorting and the absence of pagination so the agent knows one call is sufficient. For a zero-parameter, read-only listing this is complete enough to call correctly on first attempt.

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?

The tool takes zero parameters and the schema is an empty object, so the baseline is 4 and there is no parameter semantics to add. The description does not attempt to invent or explain any inputs, which is correct here.

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 ("Lists all sites") with an explicit scope qualifier: only sites "of which Kilotest has tested pages." It also distinguishes itself from the sibling listPages by framing sites as the coarser first step, so an agent can separate the two without opening a schema.

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?

Gives an explicit ordered workflow: use this first to check whether a site was tested, then listPages with the returned site identifier to check the page, before requesting a test. The condition that selects this tool over its sibling is stated outright, not inferred.

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