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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so the safety profile is covered without the description. The description adds domain context (audiences are static and manually managed) but says nothing about pagination, result ordering, or volume, which matters for a list endpoint.

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, zero filler, with the resource and its scope front-loaded. Every clause earns its place by disambiguating terminology.

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 simple read-only list tool with full annotation coverage, full schema coverage and no output schema, the definition is essentially sufficient. It only lacks any note on return shape or pagination, a minor gap given no output schema exists.

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?

There is a single optional parameter (apiKey) already fully documented in the schema at 100% coverage. The description adds no parameter meaning, so the baseline of 3 for schema-covered parameters applies.

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 and resource ("List audiences") and clarifies the terminology with "(lists)", which is genuinely useful given the product's mixed vocabulary. It does not name a sibling, but the read-only list intent is unambiguous against create_audience/delete_audience.

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?

There is no explicit when-to-use statement, but "static, manually-managed group of contacts" implicitly routes the agent away from list_segments, which is the main alternative for grouping contacts. No exclusions or prerequisites are stated.

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