List customers

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

The readOnlyHint annotation already establishes that this is a safe read, so the description only needs to add context. It discloses that pricing tier is included in the results, but says nothing about ordering, pagination, or volume limits for a full customer list.

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?

A single front-loaded sentence with no redundant or filler wording. Every element, the listing action and the included pricing tier, earns its place.

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?

With no input parameters, a read-only annotation, and an output schema covering return values, the description is close to sufficient. The only gap is operational context such as pagination or ordering behavior for a potentially large customer list.

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?

The tool takes zero parameters, so the baseline is 4 and there is no parameter meaning the description could add. Nothing in the schema is left unexplained.

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 ('List all customers') and adds the returned attribute ('their pricing tier'), so the operation is unambiguous. It does not distinguish itself from the sibling get_customer, which is the only missing piece for a 5.

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?

The word 'all' implies a bulk listing as opposed to fetching one customer, which hints at when to use it over get_customer. However, no alternative is named and no condition or exclusion is stated, leaving usage to inference.

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