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

The readOnlyHint=true and destructiveHint=false annotations already establish that this is a safe read, and the description aligns by saying 'Get'. It adds little beyond 'single ... by Id' (which is also in the schema) and QuickBooks Online as the source; no extra behavior such as auth, not-found handling, or company selection is disclosed.

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 sentence that puts the action and object first and drops filler. It is as concise as the definition can be without losing information.

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 simple get-by-id with fully documented parameters and safety annotations, the definition is mostly sufficient. The absence of an output schema means no return shape is specified, but the verb 'Get' and object 'purchase' reasonably imply the response.

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 schema fully explains id and company. The description's 'by Id' merely echoes the required parameter and adds no new semantic context.

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 exactly the operation (get), resource (purchase), system (QuickBooks Online), and lookup key (Id), making the tool's function immediately clear. It doesn't explicitly distinguish from siblings such as get_purchase_order or search_purchases, but the resource and single-by-Id semantics prevent major ambiguity.

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 when-to-use or alternative guidance is provided. An agent is not told to use search_purchases when lacking an Id or to use get_purchase_order for purchase orders, so decision support relies entirely on the name and schema.

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