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

readOnlyHint=true already tells the agent this is a safe read, so the bar is lower. The description adds useful context by naming the payload fields the agent will receive, but says nothing about lookup failure behavior when an id does not exist or about the API's rate/auth profile.

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 compact fragments covering purpose and endpoint, with the identifying information front-loaded and zero filler. It is slightly telegraphic, but nothing is wasted.

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 single-parameter read tool with no output schema, the description rounds out the picture by enumerating the returned fields, which the schema cannot convey. Only the error/not-found behavior is unaddressed, a minor gap given readOnlyHint covers safety.

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 coverage is 100% and the single parameter is fully documented ('Stock item id (from superfaktura_list_stock_items)'), so the baseline of 3 applies. The description adds no format or constraint detail beyond what the schema already states.

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+resource ('One warehouse item') and enumerates the returned fields (SKU, price, VAT, purchase price, quantity), which distinguishes it from the sibling superfaktura_list_stock_items by being singular. Sibling differentiation is implied by 'One' rather than stated explicitly, so it stops short of a 5.

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 offers no when-to-use or when-not-to-use guidance and never names superfaktura_list_stock_items as the alternative for browsing. The only routing hint ('from superfaktura_list_stock_items') lives in the schema's parameter description, not in the tool description itself.

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