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

Annotations already establish that this is a non-read-only, non-destructive create operation. The description adds valuable behavioral context beyond that: zero credit limit means prepay only, not a missing value, and credit-limit changes are separately logged. It still does not cover duplicate-customer behavior or the response shape.

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 and appropriately brief for a create tool. The final "Effects: customer created" is somewhat redundant with the opening sentence, but it still marks the side effect explicitly.

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 six-parameter create tool with full schema coverage and annotations but no output schema, the description covers purpose, a key credit-limit rule, and the creation effect. It would be stronger if it mentioned duplicate handling or whether the response returns an identifier for follow-up calls.

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 documents all six parameters, including that credit_limit is in cents. The description adds meaningful business semantics for credit_limit: zero is a real prepay position and must not be fabricated. It does not clarify what happens when credit_limit is omitted, which is a remaining gap.

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 we can sell to." It also implicitly distinguishes this operation from changing a customer's credit limit later, which is described as "its own logged command."

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 when-not-to guidance around credit limits: do not invent a limit to force an order through, because limit changes belong to an authorized, separately logged command. It does not explicitly name alternatives such as core_update_customer or crm_promote_to_customer, so it stops short of full when/when-not/alternative coverage.

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