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

With no annotations, the description carries the full burden and does disclose two valuable behavioral facts: the call is read-only and free, while downstream purchasing consumes credits. It does not cover pagination, result size, or return shape, but the cost/safety profile — the most consequential trait here — is clearly communicated.

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?

Three short clauses, front-loaded with the resource and its scope, then cost model, then safety. No filler and nothing redundant with the title.

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?

For a zero-parameter, no-output-schema listing tool, the description covers what is returned (audiences and categories) and the cost/read-only behavior. It lacks guidance on result volume or how to drill into a specific set, which is a minor gap given the tool's simplicity.

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 takes zero parameters, so the baseline is 4; there is nothing for the description to disambiguate beyond confirming the call takes no required input.

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?

States a specific verb (browse/list) and resource (pre-built audiences in the marketplace), and explicitly includes the scope 'plus their categories.' It is distinguishable at a glance from get_audience_set (single set), list_audiences, and buy_audience_set (purchase action).

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 context with 'Browsing is free; buying costs credits,' which signals this is the discovery step before a purchase, but it never names buy_audience_set or any alternative, nor states when to prefer get_audience_set or search_audience. Usage is inferable but not stated.

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