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

Annotations already declare non-read-only, non-idempotent, non-destructive, so the safety profile is covered, and the description adds the concrete endpoint (POST /customers.api) and the order-scope caveat. However, it does not disclose anything about duplicate-email handling, auth requirements, or what is returned on success.

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, each earning its place: the action, the requirement, and the scope boundary. The key constraint is front-loaded with no filler.

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 10-parameter mutation with no output schema and idempotentHint false, the description is adequate but thin: it never explains whether a duplicate customer is created or how to recover the new customer's ID, which an agent calling this really needs.

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% and the schema already marks first_name and last_name as required, so the description's note about the required names is redundant. It adds no format or constraint meaning beyond the schema.

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 the specific verb and resource ('Create a customer') and defines what a customer is ('a person who rents'), which disambiguates it from order and work-order creation. The added 'Does not create an order' clause explicitly separates it from the create_order sibling.

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?

It gives a useful boundary ('Does not create an order') and states the required fields, but never says when to use this versus list_customers/get_customer or search_member_by_email, nor what to do if the customer already exists. Usage is only implied.

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