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

Annotations already cover the mutation/safety profile (readOnlyHint=false, destructiveHint=true, idempotentHint=false, openWorldHint=true). The description adds meaningful context beyond that: it will not deduplicate, implying non-idempotent behavior and duplicate risk, and notes the underlying POST /v1/customers endpoint. It stops short of describing the return payload, which is a minor gap.

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?

Two tight sentences with the write semantics front-loaded, followed by the duplicate-avoidance guidance. No filler text.

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?

Given a simple 3-parameter create tool with full schema coverage and annotations carrying the safety profile, the description is largely sufficient. It could note what the response returns (e.g., new customer ID), but that is a small omission.

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 name/email/phone are already fully documented with types and length bounds. The description's restatement of name as required and phone/email as optional is accurate but redundant with the schema's required array.

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 an explicit verb (create) and resource (customer record) plus the service name, and the WRITE prefix signals mutation immediately. It is clearly distinguishable from siblings like zenbooker_list_customers and zenbooker_get_customer.

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?

Explicitly directs the agent to search with zenbooker_list_customers first to avoid duplicates, and explains why (the tool does not check for existing customers). This names both the alternative and the condition that selects it.

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