list_audiences

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

With no annotations, the description carries the behavioral burden. It explicitly uses 'List,' indicating a non-mutating read operation, and specifies that counts are included in the output. It does not mention pagination or rate limits, but for a zero-parameter, straightforward listing this is reasonably transparent.

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?

A single concise sentence that front-loads the action and resource, then adds the key output detail (contact counts). Every word adds value and there is no redundant content.

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?

The tool is simple, parameterless, and has no output schema. The description covers what is listed and the essential returned metric, which is sufficient for an agent to select and invoke it correctly. Minor omissions like pagination or sorting do not undermine usability.

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 tool has no parameters, so there is nothing for the description to clarify about arguments. The baseline of 4 applies because parameter semantics are irrelevant and the description need not compensate for any schema gaps.

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 states a specific verb (List) and resource (contact lists), and adds the distinguishing metric 'how many contacts each holds.' This clearly separates it from sibling tools like list_segments, list_tags, and list_broadcasts.

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 about when to use this tool versus alternatives such as list_segments or list_tags. The description implies a simple listing use case but does not state exclusions or direct the agent to a sibling when a different kind of list is needed.

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