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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds useful behavioral context by stating that this is a curated discovery tool that performs 'No new website probe', though it does not discuss rate limits or underlying data freshness beyond 'curated'.

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?

Two tight sentences, with the discovery scope front-loaded and the sibling-routing guidance immediately following. Every clause adds useful information and there is no redundant restatement.

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?

Given zero parameters, rich annotations, an output schema, and the need to distinguish from several sibling tools, the description supplies everything necessary: what is listed, that no live probe occurs, and which alternatives handle status observations and generic host checks.

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 has zero parameters, so there is nothing for the description to compensate for. Baseline 4 is appropriate for a parameterless tool, and the schema is fully covered.

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 uses a specific verb ('Discover') and enumerates exactly what the tool returns: curated service IDs, homepage URLs, measurement scopes, and official status dashboards. It also explicitly contrasts itself with get_service_status and check_website, so an agent can distinguish its role without opening the 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?

It gives explicit routing guidance: use get_service_status for existing observations, and check_website for any public hostname. Combined with 'No new website probe', it clearly establishes when this tool is appropriate and when a sibling is better.

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