get_purchase_receipt

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

Annotations already declare readOnlyHint=true, so the safety profile is covered. Beyond that, the description adds real value by disclosing what the receipt contains and describing the human_summary field, which matters because no output schema exists. It does not cover behavior on a nonexistent or unauthorized purchase_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?

Two front-loaded sentences with no filler; the purpose comes first and the output detail second. The second sentence earns its place by describing a return field that has no output schema to document it.

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 one-parameter read-only tool with annotations covering safety, the description is nearly sufficient, and it usefully compensates for the missing output schema by naming key return fields. Minor gaps remain around error/empty-result behavior.

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% with a single parameter fully documented (UUID format, required, clear meaning), so the schema does the heavy lifting. The description adds no syntax or format detail beyond it, making the baseline 3 appropriate.

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 states a specific verb ('Get') and a distinct resource ('cost-benefit receipt for a purchase'), and enumerates the returned contents (price paid, hours saved, labor cost). This separates it from siblings like list_purchases or buy_now, though it never names an alternative explicitly.

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 explicit when-to-use or when-not-to-use guidance, no prerequisites, and no mention of alternatives. The only usage hint is implicit, that human_summary is 'suitable for forwarding to the operator', which describes downstream use rather than tool selection.

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