billy_list_contact_persons

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

The description mentions 'READ-ONLY', which is a key behavioral trait. However, it does not disclose other behaviors like pagination, filtering via the optional contactId parameter, or whether the output is limited. With no annotations, the description carries full burden but adds little beyond the name.

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 very concise (two sentences). However, it lacks explanation of the parameter, which is a structural flaw. Every sentence is short but not fully informative.

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 optional parameter and the presence of many sibling list tools, the description is insufficient. It does not explain what contact persons are, how they relate to contacts, or the effect of the contactId parameter. No output schema means the agent has no idea what the tool returns.

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 only parameter, contactId, has no description in the schema (0% coverage) and the description does not explain its purpose or effect. This is a critical gap as the parameter likely filters the list.

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 the tool lists contact persons, which is specific and matches the name. However, it does not explicitly distinguish from sibling tools like billy_list_contacts (contacts vs. contact persons).

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 compared to alternatives such as billy_get_contact or billy_list_contacts. The 'READ-ONLY' label hints at safety but does not clarify context or exclusions.

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