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

Annotations already declare readOnlyHint=true, so 'Read-only' is redundant, but the description adds genuine value by disclosing the return shape (JSON:API data, attributes, relationships, pagination metadata) and the underlying endpoint GET /api/customers. With no output schema present, that return-format disclosure is what carries the read here.

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, front-loaded with the purpose, then return shape, then a safety/endpoint note. Nothing is padded and no sentence repeats the schema.

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 three optional params, nested filters, and no output schema, the description covers the essentials: what is returned and that it is read-only. It could go slightly further by noting pagination traversal or how filtering narrows results, but an agent has enough to invoke it correctly.

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%, and the schema already documents page, page_size (1–100, default 20), and filters with concrete examples and the invalid-field rejection rule. The description adds no parameter meaning beyond that, so the 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?

States a specific verb and resource: 'List the connected TOConline company's customers', which cleanly separates it from the sibling get_customer (retrieval of one) and from list_suppliers/list_products (other resources). It stops short of naming an alternative explicitly, so it lands at 4 rather than 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?

There is no statement of when to use this versus toconline_get_customer, nor any note about paging through results or when filtering is warranted. The only guidance is the implied 'list = many', leaving the agent to infer selection criteria.

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