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

There are no annotations, so the description carries the behavioral burden. It discloses that the tool is free to call, which is a useful cost-related behavior, and clarifies how the kind parameter changes the result set to include owner-fulfilled work. It does not mention auth, rate limits, or side effects, but the verb 'list' implies a read operation and the core behavioral traits are covered.

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?

Two sentences contain the essential information with no filler. The primary purpose and default behavior are front-loaded, followed by the optional parameter guidance and the free-to-call note.

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 one-parameter listing tool with no output schema and no annotations, the description is complete: it names the resource, what is returned, the optional parameter values and their effect, and the cost of calling. An agent can reasonably decide whether and how to invoke this tool without further clarification.

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 schema already documents the kind parameter with an enum and a default of data, so the baseline is 3. The description adds meaning by explaining that service and all include owner-fulfilled work, which gives an agent a reason to choose one value over another beyond the raw enum.

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 states a specific verb and resource: it lists shelves sold by Ni Biashara, with the default being data shelves. It also names the return contents (price in USD, params, job-tool name, x402 URL), which clearly distinguishes it from purchase-focused siblings like buy_shelf.

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 gives clear context for when to use it: to list shelves, with data as the default and service/all available via the kind parameter. It does not explicitly name alternatives or state when not to use it, but the context is sufficient for this simple listing tool.

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