list_contacts

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

No annotations are provided, so the description bears full responsibility for behavioral disclosure. However, it only states basic functionality without mentioning pagination, ordering, rate limits, error handling, or what happens when an invalid contact ID is provided. This is insufficient for an AI agent to anticipate behavior.

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, well-structured sentence that immediately conveys the tool's two modes. There is no redundancy or unnecessary information, making it highly concise.

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 tool's simplicity (one parameter, no output schema), the description covers the essential use cases. However, additional context about the return format (e.g., list or detail object) would improve completeness. Still, it is largely adequate for a straightforward list operation.

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 covers the sole parameter 'contact_id' with a clear description, achieving 100% coverage. The tool description does not add additional semantic meaning beyond what the schema already provides, so a baseline score of 3 is appropriate.

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 all contacts or retrieves details for a specific contact by ID. The verb 'list' and resource 'contacts' are unambiguous, and the two modes are explicitly mentioned. This effectively distinguishes it from other tools like create_contact or delete_contact.

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 implies when to use the tool (to list contacts or get details), but it does not provide guidance on when not to use it or suggest alternatives. For example, there is no indication that searching contacts by criteria might require a different tool. The guidance is functional but lacks exclusionary context.

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