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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered, yet the description still adds substantial unique behavior: no PII returned, spam excluded, test orders listed but not counted, amounts as text in the main currency unit, ISO 8601 UTC times, and a Free-plan monthly cap with omittedOverCap. The only gap is that the shape of the returned summary object is described prose-only rather than in 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?

Front-loaded with the trigger condition and example queries before the field list and caveats, and nearly every sentence delivers distinct information. It is dense and long — the Free-plan cap explanation and the list of what is not returned could be trimmed slightly — but nothing is wasted or repetitive.

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 carries the return contract itself and does so thoroughly: field list, summary contents, currency/unit formatting, and the Free-plan counting caveat with omittedOverCap. An agent has everything needed to call it and interpret the result.

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% and each of the four parameters is already documented in the schema, including the ISO 8601 format for `since` and the enum for `status`. The description adds nothing parameter-specific beyond reiterating that times are UTC, so the baseline 3 applies.

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 ('Returns the newest orders... and a summary over every order that matches') and enumerates the fields returned. It explicitly contrasts with get_order_stats for where orders came from, so an agent can distinguish it from its nearest sibling without opening a 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?

Gives concrete trigger conditions with example user utterances (「注文は何件来た？」「今日の注文を見せて」) and names the alternative tool (get_order_stats) for source/attribution questions. It also states what is NOT done here — status changes, refunds, payment settings live on the dashboard — which removes a whole class of misrouting.

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