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

Annotations already declare readOnly, openWorld, idempotent, and non-destructive behavior, so the bar for additional behavioral disclosure is lower. The description adds context beyond the annotations by indicating the response is an aggregate/summary rather than detailed member data, and 'quick' signals a lightweight operation. No contradiction with annotations.

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?

Two short sentences with no filler. The core purpose and output content are front-loaded, and the usage guidance is appended in a compact final clause.

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 adequately conveys what will be returned by listing the breakdown dimensions. It does not detail exact response formatting, but the absence of an output schema is partly compensated by the enumerative description of the aggregate result.

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?

Schema description coverage is 0%, so the description must compensate for the undocumented projectId parameter. It only echoes 'for a project,' which maps the parameter to the concept of a project but does not explain the expected format, how to obtain it, or any constraints beyond minLength: 1. The single obvious parameter mitigates, but the gap remains.

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 uses a specific verb ('Get') with a clear resource ('aggregate audience composition for a project') and enumerates the breakdowns it provides (totals, status, rating, rep, language). This makes it clearly distinct from sibling tools like sm_get_member, sm_get_member_segments, or sm_get_insights_basic.

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 final sentence, 'Use for a quick shape-of-the-list answer,' gives a clear context for when to choose this tool. It stops short of explicitly naming alternatives or saying when not to use it, but the use case is specific enough to guide selection.

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