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

Annotations already declare readOnlyHint=true, openWorldHint=false and destructiveHint=false, so the safety profile is fully covered without the description. The text adds little beyond confirming a QBO-sourced record: no auth requirements, rate limits, or failure modes for a missing Id.

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?

A single tight sentence with the verb and resource front-loaded and no filler. It is efficient, though the trailing clause is slightly convoluted for the amount of guidance it delivers.

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 read-only single-entity fetch with 100% schema coverage and no output schema, the description gives an agent everything needed to invoke it. Only richer routing language against search_classes would push it higher.

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 both 'id' and 'company' are already documented in the schema, and the description's 'by Id' simply restates the required key. Baseline 3 is appropriate when the schema carries the full burden.

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 ('Get') and resource ('a single class from QuickBooks Online') and qualifies it with 'by Id', which cleanly separates it from the plural search_classes sibling. It lacks any explicit naming of the alternative, but the singular/Id framing makes the purpose unambiguous.

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?

Offers a when-to-use condition ('when no search or write answer already holds it'), signaling this is the direct-fetch path rather than a search. The phrasing is somewhat awkward and never names search_classes explicitly, so it stops short of a clean routing rule.

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