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

Annotations already declare readOnlyHint=false and idempotentHint=false, but the description adds the concrete consequence of non-idempotency: two calls with different codes create two customers. It also mentions the POST /customers endpoint and contract-specific required-column behavior. It does not describe permissions or response shape, but that is less critical given the annotations.

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?

The description is front-loaded with WRITE, states the required fields, gives the non-idempotency consequence, and ends with the endpoint. Every sentence adds distinct operational value 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 24-parameter creation tool with no output schema, the definition covers the essentials: operation type, required parameters, non-idempotency, contract-dependent requirements, and endpoint. It stops short of describing the expected response or authentication prerequisites, but the annotations and schema fill most remaining gaps.

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 most parameter meaning is already documented. The description adds useful semantics beyond the schema by naming the three required parameters and warning that contract-level required-column settings may demand additional fields beyond the schema's required list.

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 states a specific verb and resource -- create a customer (member) -- and distinguishes it from sibling operations such as update_customer and list_customers. An agent can immediately tell that this is the creation path, not a read or update path.

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 clear usage context: it is a WRITE operation, customerCode/firstName/lastName are required, and the contract may require additional columns. It also warns that calling twice with a different code creates two customers, which is important selection guidance. However, it does not explicitly state when to use update_customer instead.

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