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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so safety is covered. The description adds behavior beyond that by disclosing the shape of what comes back (slug, name, description, listing count) even though no output schema exists, though it says nothing about ordering or volume of results.

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?

One front-loaded sentence that carries the return fields and the downstream use in minimal space. The phrasing 'the trades Wired Home Pros lists' repeats the verb 'list' awkwardly, which is a minor blemish rather than a real cost.

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?

For a zero-parameter reference lookup with no output schema, the description supplies exactly what an agent needs: the fields returned and the role of the result as a filter vocabulary for search_installers. Nothing required to invoke or use it is missing.

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, so there are no parameter semantics to explain and the baseline of 4 applies. The description correctly does not invent parameters.

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 names a specific verb (List) and resource (trades), enumerates the fields returned (slug, name, description, listing count), and states the downstream purpose of feeding the trade filter of search_installers. An agent can distinguish it from search_installers and get_installer without opening any 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 clearly establishes the use case: call this to obtain trade values usable as the trade filter in search_installers, which implicitly frames it as a prerequisite lookup step. There is no explicit 'do not use this to search installers' exclusion, but the routing intent is unambiguous.

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