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

Beyond the readOnlyHint annotation, the description discloses two real behavioral traits: ordering ('newest first') and pagination model ('as a cursor page'), plus the backing endpoint GET /v1/audiences. It does not describe auth requirements or rate limits, so it is short of a 5.

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 sentences, zero filler, with scope and ordering front-loaded before the endpoint reference. Every clause carries information an agent can use.

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-required-parameter list tool with a fully documented schema, ordering plus pagination semantics are the critical missing pieces and both are present. No output schema is supplied, so the description could say a bit more about the page shape, but it is essentially sufficient.

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 100%, so both limit and starting_after are already fully documented in the schema, including the next_cursor relationship. The description's phrase 'cursor page' merely echoes that; with the schema doing the heavy lifting, the baseline 3 is correct.

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 and resource ('List audiences') and clarifies the domain term by equating audiences with contact lists, which helps distinguish it from bird_list_contacts and bird_list_audience_contacts. It does not explicitly name a sibling to route against, so it stops short of a 5.

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?

Usage is implied by the verb and scope ('in the workspace'), but there is no explicit when-to-use guidance, no exclusions, and no mention of alternatives such as bird_list_audience_contacts for listing people inside a list. An agent can infer the intent but gets no routing help.

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