contacts_list

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

With no annotations, the description carries the full burden. It states the behavior (listing all contacts, sorted by last name) but omits the effect of the max_results parameter, which can limit the number returned. This is a notable behavioral gap, as an agent might assume 'all' always means the complete list, not just up to 50.

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, concise sentence that front-loads the key information. There is no wasted verbiage, and it is easily scannable.

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?

Although a simple tool, the description is incomplete because it omits the impact of max_results on the result set. The output schema likely covers return structure, but the parameter's limiting behavior is essential for correct invocation. Without it, the tool may return unexpected results.

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 one parameter (max_results) with 0% description coverage. The description does not even hint at this parameter or its purpose. Since schema coverage is zero, the description fails to compensate and leaves the parameter ambiguous.

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 action ('List'), the resource ('contacts'), and the scope ('all contacts'), with a specific sort order ('by last name'). This distinguishes it from sibling tools like contacts_search, which presumably filters, and contacts_list_groups, which lists groups rather than contacts.

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 given about when to use this tool versus alternatives. There is no mention of 'use this when you need the full contact list' or 'for searching, use contacts_search.' The only implied usage is that it lists all contacts, but no explicit exclusions or alternatives are provided.

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