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

No annotations exist, so the description carries the full burden. It usefully discloses a non-obvious constraint – the SIWE signature is single-use ('署名は一度だけ利用できる') – which is exactly the kind of behavior an agent cannot get elsewhere. It does not say what happens on signature reuse, whether the signature expires, or how errors/authorization failures surface.

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 short sentences, zero filler, with the result scope front-loaded and the credential constraint immediately after. Every clause earns its place.

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 annotations, no output schema, and 4 parameters at 25% schema coverage, the description should state more: pagination behavior relative to 'offset', what an order record contains, and failure modes. It covers authentication and result cardinality adequately but leaves the return shape and pagination implicit.

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 only 25%, so the description must compensate, and it partially does: it clarifies that the signature and message are a purchase-history-specific SIWE pair tied to identity verification, and that results cap at 50. However the 'offset' parameter is never mentioned and no format or limit semantics are given for 'signature'/'customer_address', leaving half the inputs unexplained.

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 names a specific verb and resource ('注文履歴を最大50件返す') and scopes the result set (max 50). It is clearly distinguishable from the product/shop/payment siblings, 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?

Usage is only implied by the phrase '購入履歴専用のSIWE署名' – the agent can infer this is the read path for order history requiring purchase-history credentials, but there is no explicit when-to-use, when-not-to-use, or pointer to any sibling tool.

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