list_contacts

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

With no annotations provided, the description fully discloses key behaviors: automatic paging, the CTM per_page cap, max_items truncation with a warning, defaulting to active sub-accounts, and allowed status values. This goes well beyond a basic list operation and gives the agent a solid understanding of side effects and limits.

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 structured into clear, purposeful sections: purpose, filters, pagination behavior, and status defaults. Every sentence adds value without fluff, making it concise yet 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 tool has 7 parameters and no annotations, the description is quite comprehensive, covering filters, pagination, truncation, and status handling. The output schema exists, so return values are already covered. The only notable omission is the account_ids parameter, which prevents a perfect score.

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 schema has 0% description coverage, so the description must compensate. It explains the name, email, and phone filters, the per_page and max_items usage, and the status enum values. However, it does not explicitly describe the account_ids parameter, leaving a minor gap in an otherwise strong compensatory effort.

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 starts with 'List contacts across sub-accounts,' which uses a specific verb (List), defines the resource (contacts), and clarifies the scope (across sub-accounts). This clearly distinguishes it from siblings like get_contact (single contact) and list_sub_accounts (accounts).

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 on filtering (name, email, phone), pagination behavior, and status defaults. It explains how to adjust scope with status values, but it does not explicitly discuss when to use this tool versus alternatives like get_contact. This aligns with 'clear context, no exclusions,' meriting a 4.

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