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

Annotations already declare readOnly, idempotent, non-destructive, so safety is covered. The description adds one real behavioral fact – that the response includes the return's lines – but says nothing about what happens when the id is missing or belongs to a cancelled/received return.

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 short sentence with zero filler and the key fact (single return plus lines) front-loaded. It is efficient rather than padded, though the brevity shades into under-specification elsewhere.

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?

The tool is simple, but with no output schema, no parameter documentation, and 0% schema coverage, the agent does not know the id format or the response shape beyond 'lines are included'. Relying entirely on annotations for the behavioral story leaves the read contract thin.

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 0% and the sole parameter return_id is undocumented in both schema and description. The description does not say whether it is an internal numeric id, a document number, or the value returned by list_returns/create_return, so the agent gets no help constructing the call.

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 and resource ('Get one return') and adds scope that the singular/plural split with list_returns implies. It conveys that line items come back with the header, which is more than the title does, but it never names list_returns as the alternative for fetching many returns.

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 guidance, no exclusions, no mention of the obvious sibling list_returns. The singular 'one' weakly implies the alternative, but the agent is left to infer that a return_id must come from a prior list/create call.

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