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

readOnlyHint=true already tells the agent this is a safe read, so the description's main added value is the pagination instruction ('Paginate with next_after') and the endpoint. It doesn't disclose defaults like active-only vs deleted records or termination behavior, which the schema happens to cover instead.

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 short sentences: what it returns, how to use the result, how to paginate. Front-loaded, no filler, and each sentence carries distinct information.

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 read-only list tool with annotations and a fully described schema, this is nearly complete: it names the return fields and the pagination cursor. Only minor gaps remain around default filtering behavior on the response side, which the parameter schema largely implies.

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 four parameters (after, before, deleted, page_size) are already fully documented with cursor semantics and page-size advice. The description only echoes the pagination hint ('next_after'), adding little beyond the schema; baseline 3 applies.

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?

Specific verb+resource ('List customer groups') with the returned fields (id, name) and endpoint stated, so an agent knows exactly what it retrieves. It doesn't explicitly contrast with list_customers or search_customers, leaving differentiation to the tool name.

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 description gives downstream usage ('Use the id as customer_group_id when creating or updating a customer') and pagination guidance, which is useful context. However, it never states when to choose this tool over the sibling list_customers/search_customers calls or what prerequisites exist.

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