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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds genuinely non-obvious behavior beyond that: deterministic ordering (owners, then admins, then members, each by email) and that all users are returned at once with no pagination. Only the absence of any auth/permission note keeps it from 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?

Three sentences, each load-bearing: what it returns, when to use it and what to forward, and the ordering/pagination contract. The most decision-relevant fact (purpose) is front-loaded with no filler.

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?

With an output schema present, return-value structure need not be explained, and the description still covers ordering, completeness of results, and intended downstream use. Nothing an agent needs to call this no-arg read tool correctly is missing.

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?

The tool takes zero parameters, so per the rubric the baseline is 4. The only 'pass their emails' remark describes what to send to sibling tools, not an argument of this one, so it neither helps nor hurts.

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 ('List') and resource ('people in this ActivitySmith account') and enumerates the returned fields (email, name, role, active device count), which cleanly separates it from list_account_devices and the other list_* siblings. An agent can identify the tool's scope without opening the schema.

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?

Gives explicit downstream usage: 'Use it to choose users for set_channel_users, or device owners for set_channel_devices; pass their emails.' It names the two consuming siblings and tells the agent what value to hand them, which is exactly the routing guidance needed.

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