billy_list_contacts

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

The description includes 'READ-ONLY', which indicates a non-destructive operation. However, with no annotations provided, the description does not disclose other behavioral traits like pagination, sorting, error behavior, or rate limits. It minimally addresses the safety profile.

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 extremely short, consisting of two phrases. While concise, it lacks necessary detail, making it less useful. Every sentence is brief but fails to earn its place by providing comprehensive guidance.

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 6 optional parameters and no output schema, the description is insufficient. It does not explain the return format, pagination behavior, or how filters interact. For a list tool with many siblings, more detail is needed to enable correct invocation.

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 input schema has 6 parameters (q, page, pageSize, countryId, isCustomer, isSupplier) with no descriptions in the schema (0% coverage). The description adds no information about these parameters, leaving the agent to guess their purpose and format.

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 'List contacts', identifying the verb (list) and resource (contacts). This distinguishes it from sibling tools like billy_get_contact (which retrieves a single contact) and billy_create_contact. However, it does not specify the scope or any filtering details.

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?

No guidance is provided on when to use this tool versus alternatives such as billy_get_contact for individual lookups or other list tools. There is no mention of required context or preconditions.

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