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

Annotations already carry the mutation signal via destructiveHint=true, so the bar is lower. The description usefully notes the endpoint (POST /customers) and that instruments and payments can later attach to the record, but it omits idempotency behavior, the uniqueness constraint's consequences, and any error/auth context.

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 sentences, front-loaded with the action and with zero padding. The endpoint reference adds value rather than noise.

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?

No output schema exists, so the description would ideally indicate what a create returns (e.g. the generated customer id), but it does not. It covers what the tool is and its side effect reasonably well for a create operation, leaving the return shape unspecified.

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 all six parameters are already documented in the schema. The description adds nothing beyond the schema for parameters, so baseline 3 is appropriate.

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 a specific verb and resource ('CREATES a customer record') and adds useful scope in the parenthetical about what can be attached to it. Distinguishing it from the get_customer sibling is easy from the verb alone, though the description never names or contrasts a sibling explicitly.

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?

No when-to-use guidance, no prerequisites, and no alternatives named. 'This ADDS data to your account' hints at the mutation intent but does not tell an agent when to choose this over e.g. checkout_create_payment.

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