billy_get_contact

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

The description states 'READ-ONLY', which is a key behavioral trait. However, with no annotations, it fails to disclose other important aspects like error handling on missing ID, authentication needs, or return format. A 3 is appropriate for minimal but correct disclosure.

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) and front-loaded with the action. While efficient, it could be slightly improved by including the parameter requirement without becoming verbose, but overall it is appropriately sized for a simple tool.

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 lack of output schema and minimal description, the tool does not explain what the agent should expect as output (e.g., a contact object) or error behaviors. For a single-parameter read operation, more context is needed for the agent to use 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 0% for the single parameter 'id', and the description does not explain it beyond the tool's purpose. The description fails to add meaning such as expected format or source of the ID, which is critical for correct invocation.

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 'Fetch one contact' clearly states the specific verb and resource, effectively distinguishing it from sibling tools like billy_list_contacts (list) and billy_create_contact (create). The 'READ-ONLY' clarifies that it does not modify data.

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 (e.g., billy_list_contacts). The minimal description does not indicate prerequisites, such as having the contact ID, nor does it explain when not to use it.

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