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

Annotations already declare readOnlyHint and openWorldHint=false, so the description adds real value on top: stable ordering ('same order as before'), default page sizes tied to query mode, and the shape of each returned record including the nullable category object. It stops short of stating total counts or what happens on an out-of-range offset.

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 the core behavior and defaults, then the parameters, then the return shape. Every clause carries information, though the parameter walkthrough is somewhat list-like and partly redundant with the schema.

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?

There is no output schema, so the description usefully covers return fields (created_at, category object with slug/name/group, null when unclassified). For a small read-only list tool with full schema coverage, the remaining gap (pagination totals, empty-result behavior) is minor.

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 coverage is 100%, so the schema already documents all five parameters. The description largely restates those definitions, adding only the slight nuance that category may be a group or a 'promoted leaf' and that q spans title, description, or URL.

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?

Opens with a specific resource and format ('Active listings as JSON') and the tool name supplies the verb. It is clearly distinct from the mutation siblings (submit_listing, upgrade_listing) and from stat tools, though it never explicitly differentiates itself from list_categories.

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 default case is stated precisely ('No query returns every listing'), which tells an agent when no parameters are needed, but there is no guidance on when to reach for this versus list_categories or get_stats, and no exclusions are given.

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