fetch

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

The annotations already declare readOnlyHint=true, so the safe read behavior is covered. The description adds no behavioral context beyond that, such as what happens when the SKU is not found, whether the response is a full inventory item, or any rate-limit considerations.

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, tightly written sentence with no filler. It front-loads the action and resource and conveys everything it intends to convey efficiently.

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 minimal one-parameter read operation, the description is mostly sufficient, but the absence of an output schema and lack of sibling differentiation mean it does not fully prepare an agent to know what response to expect or when this accessor is the right one among many.

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%, and the single 'id' parameter is already documented as 'Item SKU'. The description repeats this without adding deeper meaning, so it stays at the baseline rather than adding semantic value.

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 a specific verb ('Fetch'), resource ('eBay inventory item'), and access path ('by SKU'). It is easy to understand, but it does not differentiate itself from the sibling tool 'ebay_get_inventory_item', which appears to serve 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?

There is no guidance about when to use this tool versus alternatives such as 'ebay_get_inventory_items' or 'ebay_get_inventory_item'. With a very large sibling list, an agent would need more explicit routing information to select this tool confidently.

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