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

Annotations already cover safety (readOnly, idempotent, non-destructive, openWorld). The description adds non-obvious behavior beyond them: unavailable software is silently omitted without disclosing status, and the returned fields are named. That silent-omission quirk is exactly the kind of trait an agent would otherwise misread as 'not found'.

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?

Three short sentences, front-loaded with purpose, followed by output contents and limitations. No filler or redundancy.

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 low-complexity, single-parameter read tool with an output schema present, the description covers purpose, returns, and key limitations without needing to enumerate return fields. Minor gaps remain around partial-miss handling (e.g., fewer than requested results returned) though the omission note partially addresses this.

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 single slug parameter has 100% schema description coverage, including the 2-4 item bounds and ordering intent, so the schema does the heavy lifting. The description adds no slug-level detail (copy source, ordering semantics) beyond what the schema states, which is the expected baseline.

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 (Compare) and resource (public software listings from marketplace search) with an explicit scope (shortlist of public listings). It is clearly distinguishable from siblings like z2h_search_marketplace (discovery) and z2h_show_marketplace (single browse).

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?

Implies correct usage by tying input to search results (slugs come from z2h_search_marketplace) and explicitly states what the tool cannot do (purchase software, access private source). It does not spell out when to prefer this over z2h_get_listing for a single item, so it stops short of full explicit routing.

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