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

Annotations already indicate readOnlyHint=true and destructiveHint=false. The description adds context that results include contact counts and are scoped to the current company. However, it does not disclose pagination behavior or that 'all' lists may require multiple calls despite the limit and cursor parameters.

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 a single sentence that is concise, front-loaded, and contains no filler. Every part of the sentence contributes meaning: the action, the resource, the scope, and the returned count detail.

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?

Given the simple listing nature of the tool, the presence of an output schema, and annotations covering safety, the description is mostly complete. The only minor gap is the relationship between 'all contact lists' and the pagination parameters, which could leave an agent unsure whether one call returns everything.

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 limit and cursor parameters are already fully documented in the schema. The description adds no additional parameter-level meaning, which is acceptable given the high schema coverage.

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 action ('List'), a resource ('all contact lists for the current company'), and an additional useful detail ('with the number of contacts in each list'). This distinguishes it from sibling tools like create_contact_list, search_contacts, and get_contact_details without ambiguity.

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 provides clear context: this tool is for retrieving all contact lists scoped to the current company, with per-list contact counts. It does not explicitly name alternatives or exclusion criteria, but the scoping language makes the intended use clear relative to the sibling tools.

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