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

Annotations already declare readOnlyHint=false, idempotentHint=false and openWorldHint=true, so "WRITE" and "Not idempotent" restate structured data rather than adding to it. The description says nothing about error behavior on duplicate productCode, whether the created record can be rolled back, rate limits, or what the call returns.

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 operation type and its required inputs, then the idempotency caveat and the endpoint. Nothing extraneous.

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 21-parameter mutation with no output schema, the description leaves out what comes back (e.g., the new productId) and what happens on conflict. Interaction with smaregi_update_product and the category prerequisite are only discoverable inside the schema.

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 100%, so the schema already explains every field, including the localId-relevant categoryId reference to smaregi_list_categories and the enums-in-prose for division, taxDivision and displayFlag. The description only repeats the three required names, adding no semantics beyond the schema's own required array.

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?

"WRITE: create a product" gives a specific verb and resource, and the WRITE prefix cleanly separates it from the read siblings (smaregi_get_product, smaregi_list_products). It does not explicitly contrast with smaregi_update_product, so the distinction is inferable rather than stated.

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 guidance on when to create vs. update, what to do when a product with the same productCode already exists, or what preconditions apply (categoryId must come from smaregi_list_categories — that hint lives only in the schema). "Not idempotent" is a retry warning, not usage routing.

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