Retrieve a customer

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint=false, and destructiveHint=false, so the safety profile is fully covered. The description adds nothing beyond them — no note on error behavior for unknown ids, no mention of what is returned or whether the call is a hard lookup failure.

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?

It is short and front-loaded, but the two sentences say the same thing twice, so the second sentence does not earn its place. There is no wasted prose beyond that redundancy, but also no structure that helps the agent.

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 simple single-parameter read tool with rich annotations and a fully described schema, the definition is minimally adequate — the agent can call it correctly. It is not complete as a selector, since nothing in it helps an agent choose it over list_customers or get_customer-related siblings.

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 single `id` parameter is fully documented in the schema. The description only echoes the same `cus_…` format hint, adding no meaning beyond the structured fields; per the coverage rule this is baseline 3.

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 restates the title almost verbatim ('Retrieve a customer' / 'Retrieve a customer by id'), and the id format `cus_…` is already in the schema. The only added signal is 'by id', which weakly distinguishes it from list_customers, but the definition is effectively tautological.

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 guidance on when to use this versus list_customers, get_customer-adjacent tools, or update_customer. The agent must infer the distinction from the tool name alone; there is no explicit when/when-not or alternative routing.

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