list_marketplaces

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

With no annotations, the description correctly indicates a read-only listing operation. However, it does not disclose potential behavioral details such as pagination (though likely unnecessary due to no parameters), rate limits, or the exact meaning of 'status'. The description is adequate but not comprehensive.

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 a single, clear sentence that conveys the essential information without unnecessary words. It is appropriately concise, though it could benefit from being split into purpose and output details for improved scannability.

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 simple tool with no parameters and no output schema, the description covers the basic purpose and output scope. However, it lacks detail on the structure of the response (e.g., what fields beyond 'status' are included), making it somewhat incomplete for an agent lacking additional context.

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 no parameters, so the description adds value by indicating the output will include 'all available marketplaces and their status'. This provides semantic context beyond the empty schema, though it could be more explicit about the output fields.

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 the verb 'List' and the resource 'all available marketplaces', and specifies the output includes 'their status'. It effectively conveys the tool's function, though it does not explicitly differentiate from siblings like get_listing_details or search_marketplace.

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 description implies usage when a complete list of marketplaces with status is needed, but provides no explicit guidance on when not to use this tool or alternatives (e.g., when details of a specific marketplace are required, use get_listing_details).

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