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

Annotations already declare non-read-only, idempotent, non-destructive, closed-world, so the safety profile is carried. The description adds the scope of mutable fields, but omits important behavior: whether unspecified fields are left untouched (partial-update semantics), what archiving an audience does to its subscribers/campaigns, and any permission or verified-domain requirements for confirmation email senders.

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?

One front-loaded sentence with the action first and the field inventory after; every clause carries information. The colon-list is slightly dense but nothing is wasted or 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 9-parameter, nested-object mutation with no output schema, the description covers what can change but not how: no statement that only supplied fields are modified, no confirmation of return value, no note on prerequisites. Adequate to start, but leaves an agent guessing about partial-update behavior.

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 coverage is 67% with rich per-field descriptions (visibility enum, double opt-in, unengaged days, sender domain), so the schema does most of the work. The description's field list matches the schema but adds no syntax or constraint detail, and even omits public_description, so it is at the baseline rather than above it.

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 (rename/change) and resource (audience) and enumerates the mutable settings, so an agent can tell this is a partial update of an existing audience rather than create-audience or update-audience-subscriber. No explicit naming of siblings, but the resource+verb combination 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?

There is no when-to-use or when-not-to-use guidance: nothing says to fetch the audience first, that the audience must exist in the current workspace, or that this is the tool for settings rather than list-audiences/create-audience. The field list implies scope but not decision criteria.

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