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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=false, so the safety profile is covered. The description adds only the account scope and newest-first ordering; it says nothing about result caps or how pagination behaves in practice.

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 sentence with the verb, scope, ordering, and a useful UI analogy — nothing redundant and nothing buried.

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 read-only, zero-required-parameter list tool whose schema fully documents filtering and paging, the description plus annotations cover what an agent needs. It stops short of noting the default page size or total-count behavior, but no output schema exists to carry that, so the gap is minor.

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% and each parameter (name, page, size, type) is well documented in the schema, including the enum caveat. The description adds no parameter-level meaning beyond the account scoping, so the baseline 3 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 the account's custom audiences") plus ordering ("newest first") and anchors it to a known UI surface. It doesn't distinguish itself from audience-adjacent siblings like get_retargeting_audiences, get_matched_audiences, or list_segments, but the core purpose is unambiguous.

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 same inventory the Metadata Audiences page shows," which helps an agent that knows the UI, but there is no explicit when-to-use or when-to-prefer-an-alternative guidance, and no mention that get_audience_details is the tool for inspecting a single audience.

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