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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world. The description adds context beyond those: it requires an API key ('Needs your key') and discloses a conditional return behavior (delivery only appears 'once paid'), which is genuinely useful behavioral detail.

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?

Three short sentences, front-loaded with the core purpose before the sibling pointer and the auth note. Every clause earns its place; nothing is redundant.

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?

With no output schema, the description usefully sketches the return (status, plus delivery once paid) and covers the auth requirement. Minor gaps remain, such as behavior on an invalid or unpaid order_id, but the definition is complete enough to invoke correctly.

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?

Only one parameter, and schema coverage is 0%, so the description must carry the meaning. It conveys that order_id selects a single order, which is adequate, but adds no format, type, or provenance detail beyond that identifier role.

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 ('One order by order_id') and even previews the payload ('its status and, once paid, the delivery'). It explicitly distinguishes itself from the sibling my_orders, so an agent can route correctly without opening either schema.

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?

Names the alternative tool (my_orders) for the listing case, giving a clear when-to-use split. It does not state when-not to use it or any error conditions (e.g. unknown order_id), so it stops short of the full when/when-not/alternatives rubric.

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