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

Annotations already declare readOnlyHint=false, destructiveHint=true and idempotentHint=true, so the safety profile is covered. The description adds genuine value on top of that: it clarifies PATCH semantics (only passed fields change, omitted fields preserved) and that supplied values overwrite existing ones, which an agent could otherwise easily get wrong. It stops short of mentioning permissions, failure modes, or whether fields can be cleared.

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 terse fragments totalling one sentence, front-loaded with the WRITE marker and the essential PATCH semantics. Nothing is padded and no clause 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?

For a 25-parameter destructive mutation with no output schema, the description covers the write nature, partial-update behavior, and the endpoint. What remains unstated — auth requirements, error behavior, and how to unset a field — are minor but not negligible gaps for a destructive operation.

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% across all 25 properties, including enum-like value meanings for sex, status, and mailReceiveFlag, so the schema carries parameter meaning. The description adds no parameter-level detail beyond the general partial-update rule, which is the expected baseline-3 outcome.

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: change fields of one customer" is a specific verb + resource, and the parenthetical scopes it to a partial update of a single record. It does not explicitly contrast with smaregi_create_customer, but the create/update distinction is evident from the wording.

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 use this tool versus smaregi_create_customer or smaregi_get_customer, and no prerequisites (auth scope, whether the customer must exist) are stated. The partial-update note implies the editing scenario but names no alternative or exclusion.

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