fetch

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

Without annotations, the description should disclose behavioral traits. It only says 'Fetch,' implying a read operation, but does not mention idempotency, rate limits, required permissions, or whether the item must exist. The agent lacks key details to anticipate behavior or errors.

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, front-loaded sentence. Every word is necessary and no waste. It is appropriately sized for a simple tool with one parameter.

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?

Given the simplicity (one required param, no nested objects, no output schema), the description is minimally adequate. However, it lacks information about the return structure or error scenarios, which would be helpful for an agent. The description does not fully compensate for missing output schema or annotations.

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 description coverage is 100%, so the baseline is 3. The description adds no additional meaning beyond the schema—'SKU' is already stated. Parameter semantics are adequately conveyed by the schema; the description does not further clarify format or constraints.

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 action (Fetch) and resource (eBay inventory item) and specifies the key parameter (by SKU). It implies singular retrieval, distinguishing it from bulk operations like ebay_bulk_get_inventory_item. However, it does not explicitly differentiate from the similarly named ebay_get_inventory_item, which appears to have the same purpose.

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?

No guidance is provided on when to use this tool versus alternatives such as ebay_get_inventory_item or bulk retrieval tools. The description does not mention use contexts, prerequisites, or limitations, leaving the agent to infer from the name alone.

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