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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds behavioral details about the search ('active listings') and a ranking preference ('Prefer sellers with sales or isSeed=true'), which are useful and go beyond annotations. There is no contradiction.

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 two sentences, front-loaded with the core purpose, and contains zero wasted words. The second sentence adds actionable guidance without bloating.

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 search tool with no output schema, no parameter descriptions, and limited behavioral details, the description leaves out essential information such as result format, sorting/pagination behavior, and parameter semantics. It provides a high-level purpose but is not complete enough for an agent to invoke the tool effectively without guessing.

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 input schema has 3 parameters (q, limit, category) with zero description coverage, and the description provides no explanation of what these parameters mean or how to use them. Since the description must compensate for the lack of schema documentation, and it does not, this is a significant gap.

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 clearly states 'Search active marketplace listings' with a specific verb and resource, and distinguishes itself from the sibling 'purchase_service' by explicitly positioning this as a pre-purchase step. The '[Buy]' prefix further clarifies its context within the marketplace workflow.

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 provides clear usage context by saying 'before purchase_service', indicating when this tool should be used. It also offers selection guidance ('Prefer sellers with sales or isSeed=true'), but does not explicitly mention when not to use it or alternative search tools, so it falls just short of a 5.

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