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

Annotations already establish that this is a read-only, non-destructive, open-world operation. The description adds valuable behavioral context by naming the required auth scope (read_customers) and the endpoint path, but it omits what happens on missing/invalid IDs or any rate-limit/error behavior.

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 very short and front-loaded with the core purpose, then adds auth and endpoint details. It earns its space, though the compressed telegraphic style could be slightly more readable without losing brevity.

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 two-parameter read-only lookup with annotations covering safety and no output schema, the description provides adequate context: purpose, auth requirement, optional fields behavior, and endpoint. It could do slightly more to explain return content or not-found behavior, but nothing critical is missing.

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 both parameters. The description adds only a light usage hint about setting fields=points,membership for loyalty data, which mostly restates the schema's example rather than introducing new syntax or constraints.

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 clearly states a specific verb+resource ('One customer by id') and distinguishes it from the list/search customer siblings by emphasizing a single customer lookup. It is understandable at a glance, though it could more explicitly contrast with easystore_list_customers and easystore_search_customers.

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 provides a useful hint for when to add 'fields=points,membership' and notes the required read_customers permission. However, it does not explicitly say when to use this tool versus list_customers, search_customers, or get_customer_points, leaving alternatives largely implied.

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