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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds genuinely useful behavior beyond that: the API V3 token requirement and the cursor contract (feed the reply's next_args back as arguments), which an agent cannot infer from the schema.

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 tight sentences, front-loaded with the core purpose and filters, then auth, then paging, then the endpoint. Nothing is redundant and every clause carries 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 paged list tool with no output schema, the description covers the essentials an agent needs: filters, credentials, and the next_args pagination loop. It stops short of hinting at the supplier record shape or page-size defaults, but the operational contract is complete.

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 coverage is 100%, and the description's filter notes (partial name, exact code/CIF) largely restate the schema's own descriptions. It adds no format or edge-case detail beyond what the parameter definitions already carry, so 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 (List) and resource (suppliers) plus the precise filter semantics: name partial, code and CIF exact. This cleanly separates it from smartbill_get_supplier and smartbill_list_clients without opening any schema.

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?

Gives clear operational context: which filters exist, that the V3 token is required, and how to continue paging via next_args. It does not explicitly say when to prefer smartbill_get_supplier over this list tool, so it stops short of naming alternatives/exclusions.

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